DIY lamp post using 4x4 pressure treated wood?

It may be easier to make a post out of two 2x4's where you can use a router to cut in a V groove down the center of the face of each piece. The two V grooves facing each other would make a channel down the middle of the post.

You may want to consider the use of a PVC conduit in the channel to eliminate the possibility of rusting.

An easier procedure than cutting a the V groove would be to build your lamp posts out of four 2x4s like shown below (end view). This would result in a nice sturdy post that was 5" square with a 2" square hole down the center for the conduit. And if this was constructed from pressure treated lumber before it fully dried it will likely hold its shape as it dried out.


Sure, so long as you can make the pipe fit a faucet designed for hot water should work just fine with cold water.


Option 1, add GFCI protection
Follow this cable back to the house to the service panel.   You want the circuit to start at the service panel, stop at a receptacle inside the house, then go outside.  If it's not like that already, rewire it so it is.   Now install a GFCI receptacle in the indoor location, and feed the outdoor line off the LOAD terminals.
Now install a 3-prong receptacle on the pole, and label it

GFCI Protected
No Equipment Ground

Option 2, retrofit ground
Don't run a whole new 3-wire cable, just run a ground wire.  It does not need to follow the same route.  It does not need to go all the way to the panel, only to any grounded circuit that is also served out of the same panel.  That circuit's ground wire must be at least as large as your ground wire is required to be.
Using the pole won't work.  Ground has two purposes (to wildly oversimplify).  The post would arrest lightning just fine.   However it would fail dismally at returning fault current to the service panel.   Dirt is a poor conductor (that's why they use copper instead).   It wouldn't flow enough current to trip the breaker, and it would just sit there shocking you and anyone between you and the house.  Of course in the latter case, a GFCI will provide that protection.


"Newer more durable grouts" is kind of vague.  I assuming that the grout was a two-part epoxy, urethane based, acrylic plus silicone, or some other non-cement based grout from you have said.

In my experience these don't react with sealers and most don't need sealing.  They are however not so easy to apply correctly.  Cement based grouts leave a haze that can taken of with cheese cloth or more commonly now a scotch-brite type pad.  The non-cement products have to be cleaned very well from the face of the tile before they cure. Some products, like Custom's Fusion Pro (with is a pre-mixed acrylic and silicon resin combination) will dry quickly and cleaning water (if it is water cleanup, epoxies I've used are not)  has to be changed regularly.  The haze will stay stuck in porous materials and even with a stripper can be tough to get rid of.  Depending on what the stone surface is, and Luxor Gold is a honed finish natural limestone if I recall correctly, it can be "rehoned" with a polisher and appropriate grit to match the existing hone, this is essentially mechan.  It makes a mess to do it.  If the surface isn't too porous then a stripper can be used (if the grout has a chemical stripper that will work, most epoxies do not) to clean the grout residue from the tile.  But since it has a sealer on it, the sealer has to be removed also and natural stone needs to be sealed, after the grout has fully cured, even when many of these modern grouts don't need to be sealed themselves.

To troubleshoot what went wrong, you may take some left over tile and grout and the sealer and do some experiments to see if the problem can be replicated and what the recipe is to replicate it.  Then try methods to fix it on the test tiles to see what works best.

TL;DR  It is my guess a product like Custom's Fusion Pro was used and was not cleaned well from the surface of the tile before it dried.  The fine haze of products like these tend to off from the grout color and usually look pretty bad a day or two after grouted.  These hazes have to be either mechanically abraded off or removed with chemical strippers.  Some epoxy products do not have chemical strippers and have to be mechanically stripped. Test any attempt to mitigate the problem in an inconspicuous place if possible or preferably some left over test tiles.


How do I properly renovate the concrete floor of my balcony?

Below is what I would do, based on my understanding of what it is you're after achieving, please let me know if I get something wrong eg Have misunderstood anything or have missed any of your questions (I believe I've covered all of them below).

  From above comments: When that is covered, I want to pave the balcony with small garden rocks, I have already bought them, they are flat, glued to some farbic sieve in squares.

I'm going to assume a total thickness of 25mm (1inch) for the above material, and you know how to attach this material to the new concrete top slab. Please correct me if I'm wrong on those assumption.
I would say you want to end up with a minimum of a 50mm (2inches) step down from top of sill to finished balcony level.
Totally clear the balcony, work area (size: 710mm x 319mm)

  Do I need to clean/set up those metal parts, cover with something, to stop rust and not let the flexibility of metal handrail shatter my new layer.

Prepare and clean the existing metal hand-railing:

Use a wire-brush, steel-wool, wet & dry sandpaper to remove as much flaky/loose material as possible.
Wash down everything with a mixture of warm water and washing (dish) liquid. Rinse off thoroughly with clean water. Allow to dry, then wipe down with something like White Spirit (paint thinner).
Paint (primer) everything with a rust inhibiting primer.
Then paint/spray everything with one-coat of a good quality exterior enamel.

Prepare and clean the 90mm thick balcony concrete slab:

Refer to this question here on SE for some details/information on how to go about tackling this.

  How to set up concrete "box" (to make concrete stay in place, and stop it falling off the balcony sides), there is hardly place to connect any temporary wooden box for that, ideas?

Seeing as the balcony isn't that big (size: 710mm x 319mm) you could use something like, "Bar Clamps" or "Pole Clamps" (2 would be enough), to pin (clamp) some shuttering material to the outside faces of the existing balcony concrete slab (against the 2 shorter sides). This would probably be easier and safer to do from the balcony below (if your below neighbour would allow you that access).
Make sure the side shuttering has a "slight" fall on the top face (over a distance of 319mm, 10mm would be enough), so that the new concrete will slope away from the door (sill), thus allowing any water to drain away from the building.
You could then attach shuttering material along the front face via connecting it to the side shuttering pieces.

  Do I need any layers between building panel and my new layer?

Paint the top face of the existing balcony concrete slab and up the face of the sill with 2 coats of bitumen paint. This will provide some protection to the existing concrete from moisture penetrating down from above.

  Which concrete should I use?
  How thick should that layer be, how many sacks of that stuff will I need (will give balcony area m2 later)

If going with 50mm of less, use something like: QUIKRETE® Sand/Topping Mix
If going with 50mm of more, use something like: QUIKRETE® Crack-Resistant Concrete Mix
For your situation I think it would be best to go with the "50mm or less" option.

  How thick a metal armature will be enough for this job?
  Wire diameter of bought armature (in picture 8): ~0,9mm

That will be fine, just place a single layer in the middle of the new concrete top slab you pour.
After you finish installing your "garden rock fabric" and have allowed everything to dry properly, I would:

Have a "general" clean-up of the whole balcony area.
Paint/spray a second-coat of the good quality exterior enamel onto the existing metal handrailing.

Good luck, and please let me know if you have any questions related to what I've written above.


How to wire GFCI combination switch/receptacle

I got it figured out with the help of my electrician friend...

Pigtail hot inbound and outbound wires with one of the hot wires protruding from back of the combo switch. Send the 2nd hot wire protruding from from of the combo switch to LINE brass/hot side.

Take neutral inbound and outbound wires and pigtail to LINE silver/neutral side.

Obviously connect the grounds together.

I now have the combo switch operating it’s own outlet and have allowed for power to continue on to the next outlet downstream, though of course passing the burden of GFI protection to the next outlet.


What is the cheapest/laziest way to touch up discolored hardwood?

Get a sanding block and sand those spots to see if you can remove those stains. Then get some Polyurethane, you'll have to match the sheen, and put on three or four coats.


Winterizing: What to do with humidifiers if turning off the main water valve

I don't see why you would automatically get cracks without a humidifier.

Anyway, I strongly suggest turning off the water - it's far too risky not to. The damage from a leak will be way worse than a crack.

I would do #2: also turn off the humidifier. But: If I were really worried, I'd get a large bucket of water and leave it near a heat vent to warm up and put some water in the air.

Maybe experiment a bit before you leave see how fast it evaporates, and if it's too fast cover it partially. If too slow then put a synthetic very clean (you don't want mold) rag in it attached to something above it (to increase surface area).


Can I replace a valve's round knob with a lever?

Probably. It's hard to say with the almost nothing you've told us about the valve.

You could also mount a bar right to the round knob if that suits your shutoff mechanism. It could be spaced off a bit to present the exact size and shape expected by the device.


Would a vernal pond (as either a retention basin or a infiltration basin) be a viable solution for this drainage issue?

I don't think that digging a pond will help

The water is where it's at and the soil is saturated like a wet sponge, removing dirt for clear open water, aka a pond, is just removing the dirt in the pond, it won't change the water level.

These days the construction of houses take lot drainage into consideration but that was not the case for your older house. It looks like the surrounding area tends to slope right to your house and the low spot is at the deepest water.

Other Ways to Deal With The Water

In the picture it looks like your yard slopes down hill to a forest. You need to get water to a place lower than where it is currently, and the forest, if lower than your lowest spot near the house, is a great place for it. You would need to slope downhill to it at least 1/4" per foot of length

Dig a channel and leave it open, maybe gently slope the sides to make it look good like a old small valley or depression
Dig a ditch and put in a drainage pipe and cover it up. Place a catch basin attached to the pipe low spot near the house
To deal with it one-off style each season, rent or buy a pump and collapsible hose and pump the water over to the forest


How long should thinset dry before gluing up tub surround?

in my experience, let it dry first - just as you would let joint comound dry...dry to the touch and firm.  I've pushed the envelope on a couple of occassions and what enbds up happening is the thinset shrinks as it dries, sucking the tile in, and causing a hairline crack.


How can I turn off the power so I can safely replace a fixture?

Tom, if the spotlight still lights up, it might be sufficient to just turn off the light switch leading to the fixture. That's assuming the power enters the switch box, and there's only a hot and neutral (and ground) going to the light fixture. Tape the light switch in the off position and tell everybody to leave it alone until you're done.  ;-)

Or you can just flip breakers until the light turns off.

But even then, you have to consider the possibility that there is still power at the light fixture. Who knows what might have been wired through that same box by who-knows-who in the past?

You really need to get yourself an electrical tester. If you get the standard old solenoid-type tester (the old "wiggy" style--"Wiggy" is actually a trademark from 1918) then you have to expose the wires so you can touch the test leads directly to them.

You can pull the light fixture away from the wall or ceiling without disconnecting the wires, to give you access to the wires for testing.

If you don't want to have to disconnect wirenuts and expose the metal wires, you can get a non-contact electrical tester which can detect current from the electromagnetic field from outside the wire insulation (these units work because a weak but harmless electrical circuit is still completed between you and the ground--electromagnetism is pretty amazing).

Get something like one of the images below, which you can find for anywhere from $5 to a few hundred. Play with the tester a little bit with a couple of live circuits, or with the cord on a plugged-in lamp or something until you feel confident about how it works, then try your circuit breakers one by one until you can't detect any live wires in the light fixture box.

Then (trust me), tape the breaker in the off position with a note on it so nobody turns it back on to make toast while you're handling the wires.


How do I replace the actual chain part of the ceiling fan?

The chain is integral to the switch.   You do not reuse your old chain, the new switch comes with one.

If it won't fit through the hole, that is an extension on your chain.  Look carefully mid-chain for a place to separate it.


Need to separate 2 lights on the same 3way switch so each switch only controls 1 light

As you probably know the 3-way on diagram A is the second switch and connects to the 3 way on diagram B which in turn goes to the light.
I'm almost certain the to lights you wish to control separately are setup in series which means you cannot control them separately from the wired switches without disconnecting the second light and adding a new wire to one of the switches. Assuming the room is finished this is going to be a pain and expensive.
In terms of the fan turning on and off randomly my first question is whether the fan remote controlled? If so is it possible that something else is on the same channel?
If you really want the two lights to be controlled separately then  short of adding the wire the only option I can think to control the lights separately is to hard wire the lights to permanently on. You would then replace the now redundant switches with a wireless remote switch and wireless light/fan control unit (e.g. something like https://www.destinationlighting.com/item/levven-wireless-light-switch-kit/768453?gclid=CjwKCAjwx6WDBhBQEiwA_dP8raoGkiSgl44ImgaMoq3v0wqaHLiEuyKXy0MdGhjzMJZmtpFYdmw1DhoCqDIQAvD_BwE#home). I suspect this will be by far the easiest option.
Jonathan


If the LED strip is truely unobtainable in 10mm, then I'd be surprised.  Try checking other sources, like ebay and aliexpress etc.

If I was really stuck, then I would make a cutting block similar to those used to spiral-cut PET bottles into long strips.

You would want two razor blades mounted parallel and vertical, and a 12mm slot to guide the 12mm strip in straight.
-------------========= 1 mm waste strip
|   12mm     <--------------  10mm wide LED strip from the middle
|   wide                        This line is the 10mm output strip
|   LED      <--------------  Pull to the right by hand
-------------========= 1 mm waste strip
             .
             .
         Two razor blades in plan view, sharp edges point to the left.


Can hanging a 70 lbs punching bag from my garage ceiling cause damage?

something like this

drill from the attic side

afterthought: use lockwashers


Why are their connected pairs of black and white wires in my light and switch boxes?

Because if power comes first to the light, you need a "switch loop" to the switch.  The two necessary wires in a "switch loop" are:

Always-hot  (so the switch has a source of power to convey onward) preferred color black.
Switched-hot (hot when the switch is on, obviously) preferred color red.

On hot wires, any particular color is not required, it simply needs to be not white gray or green.  These are mild preferences.
Now if you look at the North American market for cables, you'll find a whole lot of 2-wire+gnd cables that have black and white wires.  You will not find any cables that are black and red.  So wiring a switch loop presents a cable supply problem.
Rules for re-tasking the white wire
The cure to that problem, post-2011, is to require neutral to be brought on switch loops separately and also, which means  you use /3 cable which is black-white-red.  Solved.
However, prior to 2011, you would re-designate the white wire to be a hot.  We have specific rules for that.

White must be neutral if neutral is in the cable.  Otherwise
White must be always-hot if that is in the cable (but neutral isn't).  Otherwise
White can never be switched-hot to the lamp. (which leaves "traveler").

So, on a pre-2011 /2 switch loop, white will always be always-hot, and black will be switched-hot.  It has to be that way; the reverse would violate two rules.
Because if the were exchanged, both wires to the lamp would be white.  How on earth would  you tell which is neutral?  That would be bad, since electricians notoriously refuse to mark the wires with phase tape.
Now, neutrals must be marked
Also, neutral wires re-assigned to a "hot" must be marked with electrical tape or paint.  Yours are not properly marked, but on the other hand that requirement came into Code in the first decade of the 21st century.  Feel free to install the marking.
The marking also does the very useful thing of telling you which of these two cables is a switch loop.


Is everything properly vented?  A stopped up vent would be something above the toilets that could cause enough back-pressure to cause a clog.  Check the vent on the roof.

How old is the house?  If you're dealing with something old, you could have a drum trap or some other kludge that could be causing funny effects like repeated clogs.  Furthermore, the house settling could have caused the plumbing to lose the proper pitch.  Improper pitch would mean things wouldn't drain properly, and you'd get clogs.

Do you have a septic system, cesspool, or sewers?  If it's sewers you might have a problem with back pressure from them stopping things up.

It could be a check valve that isn't opening (possibly due to back pressure from the sewers mentioned above).

Do you have young children?  If they put something down the line that they weren't supposed to and it's deep enough that the TVing doesn't catch it, that could be a cause.


There are line voltage thermostats,  I use these for controlling electric heaters no battery a simple 2 pole switch with a temp dial. T522-w is the model I use 50-90 F temp range 120-240 at 22 amps 277v @ 18 amps I think it was close to 18$ at Platt but you may be able to find it cheaper online I believe when I ordered these there were some ~12$  but I needed 20 amp minimum 240V. , Added just checked online and you can find what you want using line voltage thermostat. Honeywell has one 13.95 (sold by Amazon) it's a 4 wire you only need to use 1 set, cap or tape the other set these are much heavier duty than your fan needs so they should last.


How do I ground a TV antenna on my shed with the cable running underground to my house?

At the shed
Grounding Electrode
The first thing you'll need to do, is to install an approved grounding electrode at the shed. For this answer, I'll assume a 5/8" x 8' grounding rod will be installed.
Bond the Mast
You'll have to bond the mast of the antenna to the newly installed grounding rod, which you'll do using a 10 AWG copper conductor. You'll attach the #10 conductor to the ground rod, using a fitting approved for the purpose. This fitting is only allowed to attach this single wire to the rod, so you can't use it to attach multiple wires.
Bonding the Electrodes
A bonding jumper of not less than 6 AWG copper (or equivalent) should be connected between this new ground rod, and the grounding electrode of the house.
Grounding the Cable
You'll want to run a coaxial cable with a built-in ground wire, from the antenna to the house. Otherwise you'll have to pull a 10 AWG grounding conductor along with the cable.
At the House
Connect the Cable
The coaxial cable should be attached to an approved Antenna Discharge Unit, before it enters the house.
NOTE: When shopping for an Antenna Discharge Unit, you'll want to look for a device that is listed to comply with ANSI/UL 452 "Antenna - Discharge Units".
Grounding
How the cable and ADU are grounded, completely depends on your grounding system. I'll cover two common methods, which should give you a good idea of how to handle it.
Intersystem Bonding Termination
The easiest method, is if your house has an Intersystem Bonding Termination. This is typically a terminal affixed to the outside of the service equipment enclosure, or a terminal on the outside of the house that is connected to the service equipment.  In this case, you'll simply attach the ADU and cable grounding conductor to the IBT.

Grounding Electrode
If there is no IBT, you can connect the grounding conductors to the grounding electrode at the house.

No Intersystem Bonding Termination or Grounding Electrode
If your house is really old, you might have neither an Intersystem Bonding Termination, nor a Grounding Electrode. In this case, you can use any of the approved grounding electrodes described in the National Electrical Code article 250.52.


Good way to remove something from a bathroom sink overflow drain?

I'd be going at it with a strongest vacuum you can come up with. Maybe put a nylon stocking over the end of the hose so the earring doesn't get damaged flying down the pipe.


How to remove baseboard installed behind hardwood floor?

A tool that may be very handy in this situation is an oscillating tool similar to this one:

Picture Source
Not trying to promote any one brand, although the above shown is a good one, there are many brands to choose from. One thing to note is that there are universal blade types and then some manufacturers have their own blade holding design. Highly suggested to select an oscillating tool that uses the universal blade style.
With the wood saw blade that is about 1 1/2" wide you can easily poke the blade and cut down at an angle into the space between the wall and hardwood floor to cut up the old molding into pieces. This should make removal far easier.
There are some blades that could be used to cut off nails as well. This could be handy for you to try to sneak the blade down behind the baseboard to cut off the nails flush with the wall. If you do use this strategy do note that quality blades for these tools are fairly pricey and nail cutting has a tendency to dull the blades much faster than when cutting just wood.


any possibility that I may have damaged a wire in the wall?

I have seen many damaged wires inside walls when remodeling, some with the outside jacket and both the conductors and ground exposed. Some have even damaged the wires because of visible arcs I know the breaker was tripped. Others just skinned the wires or the jacket (this doesn’t include the wires I was called to repair where they were severed in the walls). I was quite surprised on a few that they continued to work. All of this said it takes quite a bit of friction to cut through a unsupported piece of Romex. It sounds like you were careful and if you cannot see any damage and did not trip the breaker or GFCI things are probably ok. I would check the light and fan as that could have been a switched cable and the reason it did not show as hot was it was turned off. Then we can think of all the calls where the wires were cut. I would not be worried about most plastic anchors except the self drilling type. Of course the only way to know for absolute sure is to open the wall or use a bore scope to inspect but my guess with no arcs and sparks , tripped breakers or getting shocked if everything still works it’s probably fine. The last quick thing is all of these anchors are usually shorter than 1-1/4” the romex is supposed to be in holes or stapled that far back , so it was probably flopping around making it harder to cut through the insulation.


The only time I ran into something similar it was due to a failed anti-sweat mixing valve on a toilet that allowed back-flow through the hot water pipes. That would also explain in your case why the kitchen sink doesn't seem to be effected by the issue.

About the only way I can think of to test this theory (without opening walls) would be if you can cut your cold water off to the bathrooms without cutting the supply to the hot water heater. In the unlikely event that you can do that, your toilets would still be able to fill from the hot water line when flushed.


Why are ground wires sometimes not insulated?

Cost, mostly
Whether your grounding conductors are bare, insulated, or not even a wire to begin with depends on what wiring method you are working with.  NM, because it's made in large quantities, uses a bare grounding wire to save cost (likewise with UF and most SE cables, as those pennies add up at industrial scales).  On the other hand, if your house is wired using armored cable (AC), there are no ground wires, because the metal cable armor serves as the ground with the aid of a thin "bonding strip" to prevent "choking" of fault currents caused by stray inductive interactions.  That lack of grounding wires is also a notable feature of many installs done in metal conduit, as the conduit itself then becomes the grounding conductor.
Furthermore, some wiring methods aren't uniform in how they handle this; it's legal (and occasionally required) to run a separate equipment grounding conductor in metal conduit, and in most (albeit not all!) cases, equipment grounding conductors inside conduits can be either bare or insulated.  Likewise, metal-clad cable usually uses an insulated grounding conductor, but can sometimes be found with a bare grounding conductor, or in configurations where the armor is the grounding means.


How can I attach stainless steel utensils to aluminium posts?

You will have better luck brazing the stainless steel (which has nickel and chromium) to a brass or bronze post.  Brazing is a hotter form of soldering,  You might inquire if a jeweler would silver solder it for you.  Other wise, torches, special flux and special solder are needed.

A less expensive option would be a better grade of epoxy.  System 3 or some of the 3M industrial epoxies.  As Chris said, there must be a GOOD MECHANICAL fit first, the part shapes must align closely to allow the adhesive to bind.

On another note, you should try to abrade both parts in the contact area to give the adhesive a "toothing" point to grab.


Adding custom secondary glazing to existing frames

I actually did a similar thing custom plant room I built with 12” wide 4’ tall windows on 3 side (about 20 total). Standard glazing but thought I should make these double pane so I cleaned the inside and added the inside glass well sealed and it looked wonderful, made the room much warmer.
The first year I noticed some slight condensation smiles on the windows, by the 3rd year mold growing between the glass (the frame work was all cedar so a natural inhibitor) I pulled the inside glass on the 4th year and was going to add desiccant blocks to absorb the moisture but in that short time the cedar had rotted out the mold had covered it so it was not obvious the extent of the damage.
I replaced the bottom sill and added a thin copper plate and sealed everything up but left a weep hole. That lasted until a few years ago we decided to remove the room because the package heater had died and it was going to need a new roof.
The bottom spacer between most of the windows was spongy but it was not bad for 25years, make sure to allow moisture to escape and I would suggest a metal sill or covering so it won’t won’t rot out as quickly as my first attempt did.


When water on kitchen sink is turned up, the water flow gets excessively choppy

I'm still not certain why exactly this happened, but removing the filter fixed the thumping/choppy problem, and replacing the aerator fixed the second gust of water problem.

My suspicion at this point is that the filter either just spontaneously failed, or something in the water conditions around the time my neighbor had his problem caused a buildup of debris or something like that. We hadn't replaced the filter cartridge in it for some time anyhow (my wife found that it didn't seem to affect the water's taste much), so it was not a huge loss to us, just a baffling mystery at the time.


Can Thinset be used for covering cement driveway or garage cracks and small holes?

Not the best option for the problem.

This product may help


Those are the modern European colors of brown=hot, blue=neutral and as always green=ground... Europe puts a yellow stripe on it.

All of these converge onto a 3-row terminal block, which is the usual method of interconnect in Europe.  Note that all the wires to that terminal block enter the same side.   That tells me the other side is intended for the external power connection.  That's where you hook it up. There are screws to clamp the wire, looks like the screws are on the other side.

I assume the unit is meant to be permanently installed and hardwired.  If you put a flexible cord-and-plug on it, make sure to have proper strain relief on the cord - preferably into a metal hole.   The mounting area there is plastic and you could damage it with a hard yank on a cord.

The receptacle on the white part has nothing to do with supplying power to the unit.  Once it is hooked up, this is a convenience outlet for small appliances, and appears to be the CEE 7/5 type common in Czech Republic, Austria and France.  The ground may not work with other styles of Euro plugs, and you may be able to change the receptacle to a type more convenient to you.


Can a plumbing vent go up and then back down to the connection with the vent stack?

905.2 Grade.
All vent and branch vent pipes shall
be so graded and connected as to drain
back to the drainage pipe by gravity.
(2006 International Plumbing Code).

This might prevent you from doing what you want, since your lower horizontal connection would have to slope toward the stack. Not sure if this is allowed or not, but it might be something to look into.


Tester shows Circuit wired correctly but GFCI Trips under smallest load

White neutral is connected to the panel neutral bus (verified not
ground). The black wire from the 10-3 is connected to breaker.

Last I checked, (I don't use GFCI breakers, normally, I just put a GFCI as the first thing in line) the neutral needs to connect to the GFCI breaker neutral connection (and depending on design, you may need to connect a pigtail from the breaker to the neutral buss) otherwise the GFCI cannot possibly work.
A GFCI compares the current on the hot and neutral, and trips the GFCI function on a difference between them (5 mA nominal) - if it's not seeing the neutral return current, it will see an imbalance from the hot it does see and the neutral which it will see as 0mA if the neutral wire is not connected to it correctly.


How to deal with Densheild to drywall transition disparity

I think the difference appears to be minimal and you can just leave it.
Take a tile and place in on the denshield so it overlaps the drywall and place the edge trim behind the tile, if the gap between the back of the edge trim and the drywall is an 1/8" or less it will be fine.
A little extra thinset will fill the difference in the depth.
The extruded aluminum edging may not sit flush or down tight to the drywall but that can be hidden with a bead of caulking.


When is it generally safe/acceptable to use a wire nut?

Wire nuts come in a lot of different sizes and styles, just look at this PDF.  This brochure is from Ideal and go to page 20 for the wire size chart.  I used information from Ideal not because I think they are better than others but I'm more familiar with them.

@BMitch is right about mixing AL & CU, but there are wire nuts for those applications as well.  Most of these say that you CANNOT use with aluminum to aluminum.  Weird.

While I don't think its a problem on this site, you can use most wire nuts with 600 volt maximum.  Normally the colors dictate what sizes you can use with what wires and a lot of times these will overlap one another.  Yellow, tan, red, and the large grey will allow you to use 2 - #12's with each.  Yellow allows 1 to 3 #12's while the large grey allows 2 to 6 # 12's.  The colors and the represented wire sizes accepted is pretty much accepted by most manufacturers.

Direct burial wire nuts are available.  They are 'gel' filled and have a thicker shell.  I don't know if I would direct bury one except for landscape lighting, but they are ideal for being used in damp, moist areas like pole lights.

Anything larger than the listed size should be used with split bolts, which gets treated completely different.


Uneven paint on a smooth and primed wall

Paint will not fill holes, voids, etc very well.  It CAN do it, but it takes many coats and will still never look right.

If you want a smooth surface when you paint, you need to start with a smooth surface.

For a wall like this, go over the whole wall with medium grit (120ish) sand paper to knock down any high spots and roughen up the surface a bit.

Then, using a very wide blade trowel, apply a very thin "skim coat" of joint compound (light duty will be fine) to the entire wall.  You're not looking to build up the wall - instead you're looking to fill in all the voids without adding to the overall thickness.  Hold the blade of the scraper at a 45° angle, apply the compound evenly but with a fair amount of pressure where the edge of the blade meets the wall to keep it very thin.

Once the compound is mostly dried (not soft to the touch but not bone dry), take a SLIGHTLY DAMP, LARGE (big as you can find) sponge and go over the wall lightly to -- well think of it kind of like buffing the wall.  Only don't do lots of circles...  just go over the wall to take down any ridges/lines left behind and get that nice smooth surface.

Finally PRIME the wall, then paint.


Dishwasher plug blocking disposal outlet

Re-wire the outlet so the top one is on the switch instead of the bottom one. Is this even possible, and if so, considering I've never done it before and it's under the kitchen sink without much room, how hard would this be?

This should be very straightforward. There are actually two different configurations possible. Find the one or two breakers and turn them off. The catch is that it could be one (hot split, 1/2 to switch and top receptacle, 1/2 to bottom receptacle) or it could be two (most likely as an MWBC, one hot to each 1/2). We can't guess which one it is. If there are two breakers then they should be a pair (technically, common shut-off, in reality almost always an actual "double breaker").
After turning off the breaker(s), use a non-contact tester to make sure there is no power. Just in case. Then take off the cover plate and remove the receptacle from the wall but don't remove any wires yet. You should see two colored hot wires on the brass screws (or backstabs near the brass screws) and one or two white neutral wires on the silver screws.
If you have only one breaker involved then you should only have one neutral wire. If you have two breakers then you may have one neutral (MWBC) or two neutrals (two independent circuits - unlikely).
The actual work:

Swap the two hot wires. If they are in backstab connections, move to the brass screws (and flip top vs. bottom). If they are on the brass screws, just flip top vs. bottom.
If there are two neutral wires, swap them as well.

Put it all back together, turn on power and you should find the switch now operates the bottom receptacle instead of the top receptacle.

Put the dishwasher in the switch outlet, and tape the switch permanently on. Put a smart plug between the disposal plug and the wall, so I can control the disposal with my cell phone.

DO NOT DO THIS! EVER!
This is not only not "normal", it is exceedingly dangerous. The reason the disposal switch is normally above the sink is so that you can see exactly what is going on when you turn on the disposal and so that you can immediately turn it off if there is a problem. If you control by phone, numerous scenarios could happen, including "someone else borrows your phone to make a call and accidentally starts the App while you are working in the sink" and "phone crashes right after you turned on the disposal or the phone rings while the disposal is on, will the App stay focused?" etc. DO NOT DO THIS! EVER!

Put the dishwasher on an extension cord. I've read this is a really bad idea, but are there particular extension cords that would make this safe?

This is OK as a temporary solution, until you rewire the receptacles.

Cut the cord and put a new end on it. I've never done this, so is this difficult or dangerous?

Not cut the cord, REPLACE the cord. This actually is not too hard on a properly designed appliance. But the work involved is comparable to "swap wires in the receptacles" and doing that doesn't actually cost you anything, where this will cost you a new cord.


Painting walls after taking down wallpaper

This really depends on how the old wallpaper was installed, what type it was, if the walls were primed before and so on.

Best case scenario (happens 10-15% of the time I have to redo walls) is that your walls were painted/primed, they didn't glob on glue, the glue has broken down due to age and you simply pull off wallpaper and paint.

Good case scenario is that after you pull off wallpaper you are left with some felt/paper or some glue residue.  Here I suggest using super hot water and vinegar and a grout sponge (rough side).  If it is really bad you can go through with fine drywall sandpaper (black mesh).

Bad case scenario is wall paper has to be thoroughly wetted and scraped off using a wall paper scraper.  Then you have to fix issues with drywall mud and sand that down, prime, and paint.

Worst case scenario is wall paper is stuck on the wall and the walls haven't been primed.  Wall paper tears off drywall top layer no matter what you do.  At that point its a test of will.  Will you tear down all the drywall (the sane/faster way but also "harder") or will you diligently scrape off every single inch, do tons of touch up which equates to skimming mud on the whole wall...


None of the three options you've shown are likely to add substantial strength or stiffness to your floor. To add either, you'll need a single, continuous additional member to span the majority of the joist length.

The blocking is probably not critical, especially if you're doubling the joists for most of their length. It's typically installed to prevent deflection, and that's not a significant concern where you have doubled joists.

My suggestion would be to remove blocking from every second joist space and double for 80% of the joist's length in those spaces. The remaining blocking will serve to stabilize all joists.

If the original joists are sound (not showing rot), compression is probably not a concern. Even a tub of water doesn't add up to enough weight to compress healthy lumber.

Regarding your comments on the original ideas, you will see some gains if 1) you fit your additional blocking extremely well, and 2) you fasten it all together with screws and construction adhesive. The result will essentially be a load-bridging honeycomb that will improve rigidity and strength. However, the flooring already provides substantial load-sharing, so gains will be minimal.

The primary reason that it's not widely hailed is that it's a very putzy, time-intensive plan that's ultimately inferior to a proper joist sistering. You'll spend more time cutting and fitting all those blocks than you would tearing out half the blocking and slapping new lumber alongside the joists.


How do you rough in lighting for drop ceilings?

Not an electrician.
My first thought would be to do the rough in by putting an electrical box on the actual ceiling.  In this box wire your conventional wire to a short length of romex.  The romex then is wired to your fixture when you hang the drop ceiling.
I don't think conduit would be required for the supply to these boxes, but it's not covered in my "Alberta Electrical Code Simplified" Doing a quick google finds that NM is fine for above suspended ceilings.  What is frowned upon is running the wire just on top of the support tracks.
My thought is that romex is more tolerant of being bent, and since you can't guarantee it be secured within 1 foot of the fixture, whatever you put in should tolerate bending.
I also know that when fiddling around with hanging ceiling you bump tiles into things.


You could add another outlet to the garage side but it will probably need to be offset from the current box. With the new outlet in the garage it will need to be a GFCI type outlet to meet code.
A old work box would be the easiest to add.


No. There is nothing you can, or should do to fix this.
Don't touch it, don't go near it, don't even look at it anymore.  Get off the roof, and call the local power company or an Electrician.
Service entrance cables do not have overcurrent protection and will shock you until the transformer blows, the wire burns and breaks, or contact with the line has been broken. All of which will likely happen long after you are dead.


How do I/can I install a dimmer without a ground?

A dimmer that buzzes is using an obsolete way to dim. It's also buzzing all your surge suppressors and the AM radio for half the neighborhood.

Grounds are not used in any way whatsoever as part of the functioning circuit.  Electrons should never move on a ground path.  So the dimmer shouldn't need it to function, but a newer, better dimmer might need a neutral wire.  Make sure you are considering future LEDs when picking a dimmer.  The better LEDs (GE, Cree) are really quite good now, and it's time to say goodbye to incandescents.

I do see a ground wire back in there.  It also looks like a steel junction box.  It is likely the ground wire is either strapped to the box (typically with a #10-32 screw) or is otherwise attachable with a wire nut, possibly already attached to other wires.

You also see the metal yoke on the switch.  That is meant to be ground.  You see where the yoke is resting on plaster, not the steel box itself, so the ground path there is weak - depending on the metal screw.  Because of that, I'd use a wired connection of bare (or bareD) wire to go from an attachment point to the ground screw on the switch.

By the way, that little paper square on the bottom of the box, is designed to go on the screws on the switch yoke.  You slide or screw it onto the screw, and now it will stay captive and not fall out.  Sometimes they get unscrewed by accident as you're removing the switch.


Is it normal for an air compressor's tank to have something inside it?

No, there should be nothing loose inside there by design. If it is a used compressor, then I'd expect it is some rust that has broken loose. If it is new, then it is probably a piece of scale from when the tank was welded, or some other junk that got left in the tank. If it was a cheap compressor, then you got what you paid for.


I'm not sure if laminating a sister to each beam would count as three inches (I don't see why not if done properly, for at least as far as deflection is concerned; load calculation I have no idea), then it would be 3 x 7.75, and according to your link (L/673) that's OK for tile.

12 feet of 2x8 is pushing it, for sure. Sister each beam and install blocking.

My answer here, provides what insight I have for laminating beams; e.g., nailing schedules.


Answering my own question: it looks like the best practice is to cap the pipe after sawing it off: https://www.youtube.com/watch?v=6lBqLTvtVrw


Lots and lots and lots of spaces.
Electricity works for us. It does our bidding.  Running out of spaces is a huge, project-killing problem.  And spaces are dirt cheap when you buy it (rather more expensive after the fact)... so we earnestly advise gross overkill on panel spaces.
So when you said "150A panel like this one" I thought "30 space panel for a shed?  Now you're talking!"
Seriously.  30 spaces is not too many.
So yeah, if you want to get a similar subpanel, go for it.  Although that one is a classic "CH" panel, I have 2 myself and they are my brand of choice.  They are now wider because of a rule change on wire bending radius.  14.25" so they fit between joists.
If you're thinking "I'll free up THAT panel when I upgrade my panel" I would not do that.  I would leave this panel where it is and put a new 200A CH panel right next to it, then have that feed this existing panel.  Way less work lol.
Main breaker size in a subpanel
Subpanels don't need main breakers at all.  What they need is disconnect switches if they are in outbuildings (no breezeway between them).
Actual disconnect switches can get pretty expensive, and just the way they price service panels, it's cheaper to buy a "main breaker" panel and completely ignore the number on the breaker handle.
So yeah, a 150A main breaker panel will work for ANY feeder size, though a feeder larger than 150A would be wasted.
The feeder MUST be fused
You mentioned 150A feeder to the subpanel.  However you can't "tee" off the un-fused, always-energized feed coming off your meter and carry it to the subpanel. The run to the subpanel must be protected by a breaker.  And here's the rubaw: the largest branch circuit breaker in the CH line is 125A.
To go off on my tangent about a panel upgrade, one option is to replace the meter pan with a "meter-main".  It contains both meter and main breaker (some even have a micro-panel with 8 spaces that is perfect for feeding outbuildings).  At that point the wires coming off the meter are fused, and you could "tee" off them at your leisure.  It's a complicated job that requires permit/inspection, but the scope of work is small.
So the feeder wire must be behind a breaker, and the breaker decides wire size.  Since you're in conduit, we're talking THWN/XHHW individual wires, and those are allowed to run hotter than UF/NM cable, so amps may not be what you expect.

30A -- #10 copper wire
50A -- #8 copper wire or #6 aluminum
65A using 70A breaker -- #6 copper or #4 aluminum
100A -- #1 aluminum
120A using 125A breaker (largest 2-space breaker) -- 1/0 aluminum
Full 150A -- 2/0 aluminum for you

You can actually provision full 150A on 2/0 wire (135A normally), because of Rule 310.15(B)(7) which says "no feeder needs to be larger than 83% of the service size", that's 124.5A in your case.  Services "round down" on breaker size, feeders "round up" as above.
#6 or larger is where you start thinking about aluminum wire.  Much above that, aluminum is the wiser choice. The lore about "dangerous aluminum" never applied to large feeder like this.
Grounds must be #10 for up to 60A, #8Cu/#6Al for 61-100A, and #6Cu/#4Al for 101-200A.  That's decided by wire capacity not breaker size! (if conductors are upsized e.g. for voltage drop, grounds must be too).
You aren't going far enough for voltage drop to matter at 240V, I don't even crunch the numbers until 180'. However I also like to recalculate for a single large 120V load, and on smaller feeders (#12-#10) that can become an issue. Even so, you're just on the cusp; I don't even bother crunching the numbers on that until 90'.
Your questions
Is 150A overkill?  Yes, until the day you're at the Tesla dealer who asks "do you want the slow charger or the fast charger?"  Prior to the existence of EVSEs, most people had little chance to use that much.  But there's always another gadget, and always will be.
Is my panel big enough? Always.  Panel capacity isn't decided by subpanels or spaces, it's decided by load calculations based on the loads of the house.
How do I choose the best size sub?  Spaces: PLENTY.  Amps: Any size, at least enough to exploit whatever feeder you're willing to pay for.
Remember you need 6" of cover over top of the conduit, not a 6" trench.  Also must be 12" under vehicle drives.


Microwave cavity paint comes up on my Amazon page...
QB Products 98QBP0302 Microwave Cavity Paint, 6 oz, Snow White
by Appliance Pros
Learn more: https://www.amazon.com/dp/B00IU6MNAG/ref=cm_sw_em_r_mt_dp_uKlMFb0DB31Q0


Is it kosher to splice wiring in the "can" portion of recessed LED lighting?

You are in code as long as there is enough room for every thing and you do not have to modify the can. The can would be considered the junction box. Also you need to make sure you have installed the correct cans for the type of insulation that is around the can, you should be okay. ie If the can is installed in an area that is surrounded by insulation the can must be rated for it, or a shroud must be built as an air gap for those that are not.

Without the correct can, if the can has a thermal overload, the thermal overload will over heat and shut down power to the light and become a nuisance.


Want to switch to tankless, but can I use my existing wiring?

If a heater requires 8 AWG wire,  it's because it requires more electricity than a smaller wire is capable of safely delivering.  If you used the 12 AWG wire, first the 20A breaker would trip, but if that was upgraded (DO NOT) then the wire itself would turn into a heater and burn down the house.

What I'm saying here is that when too much electricity is run through a wire that is too small, it heats up.  Wire sizes are based on keeping a wire cool enough to not cause a fire when it's used.  Wire sizes are hard requirements, not suggestions.

The only option here is to run new wire or choose a smaller water heater.


How serious is mildew on the ceiling of the top floor of a house?

It probably means that you have a hole in the roof that was large enough to drip enough water to stain the ceiling (which doesn't take much, really) but small enough so that the amount of water dripping through is contained by the ceiling and does not leak through inside the room.  I would try to get the coordinates of the stain on the roof and get on the roof, project it there, try to find the hole and patch it.


How can I prevent decay in a deck post resting on the house footing?

Yes, I like the concrete idea too. However, there are 3 issues to consider: 1) hold it up, 2) hold it down and 3) hold it from rotating.

To hold it up you'll need to pour the 5 footings on undisturbed soil or compacted gravel that will support the load of the roof plus snow load. Minimum snow load is 25 pounds per square foot (unless you live in the deep south it could be less or in the north it could be more). So, 20' x 15' x 25 psf = 7,500 lbs. load.  Half rests on house and half on 5 new posts....therefore 3,750 lbs. on posts or 750 lbs. on each post. Soil bearing is typically 1500 per square foot or more. So, a 12" x 12" (or so) footing is adequate.

To hold it down you'll need sufficient amount of concrete to hold it down. Wind uplift is about 20 lbs. per square foot (max.) unless in tornado area or on the coast. So, 20' x 15' x 30 lbs. per square foot = 6,000 lbs.  Again, half held down along edge of house and half by the 5 footings = 3,000 lbs. or 600 lbs. by each post/footing. The minimum size of each footing needs to be 2' x 2' x 12" deep, which equals 600 lbs. each.
Rotation is more difficult, but without walls, then the wind will not provide rotation...therefore it's ignored.

Likewise with seismic concerns. Too complicated for this discussion.
NOTE: Make sure each post connector is rated for 600 lbs. uplift and 750 lbs. bearing...at both top and bottom of each post.
The roof connection for bearing to the house should be 3,750 lbs. or 3,750 lbs. / 20' = 188 lbs. per foot. The roof connection for uplift to the house is 3,000 lbs. or 3,000 lbs. / 20' = 150 lbs. per foot. You can find clips at local hardware store for this (house side) connection.
Dryrot, decay and pests occur when posts are in a wet situation, (I.e.: below grade.) Keep all post supports a minimum of 6" above adjacent grade...code requirement. If you can't , and the post has to be below grade, then at least treat it like a fence post: use pressure treated wood.

Use a wood suitable for exterior use...ask the lumber yard salesman for recommendation for wood available in your area.

Good luck. It's not that complicated. I've made it complicated to give you the sizes of footings, clips, etc.


How should I raise the subfloor in one room to match another?

I would always remove floating laminate before installing a new flooring. For one thing, it's probably not an approved substrate for your new product--you'll likely void the warranty by leaving it in. For another, you open yourself up to unwanted movement and noise.
So yes, remove the laminate and its underlayment (felt, foam) if present. Then assess the height difference. If it's about 3/4" like you describe, I'd overlay and screw down 3/4" tongue-and-groove OSB. It's about as cheap as you'll find for 3/4" material.
If you then have a small height discrepancy you can skim some floor leveler across that transition, feathering it out with a straight trowel for at least 12-16".


Why does my shower feed do a long loop into my garage?

Hard to know without having them to ask.

Possibly thinking of having a utility sink or clothes washer in the garage? My other thought was considering fitment of a pre-warming arrangement but that would only need the cold line (and a drain pump feeding the shower drain water to a heat exchanger on the cold line, for a shower not on an upper level. The pump energy being considerably less than is saved on water heating when this is done right.)


Water pump and pipe size for maximum water intake?

To achieve the maximum flow keep your pump at ground level. With a 1/2" slightly pressurized intake it may help to put 3/4" out put to the water tank but much larger would probably be a waste of $.  Make sure to have water in the pump at all times the shaft seals are usually ceramic with no water they overheat and crack. This would be another reason to keep the pump at ground level since there is low water pressure it will be difficult for the pump to prime. If you do have pressure on the 2nd floor it may work ok there if the pump max head pressure cannot make it to the roof. If memory serves fresh water weighs .43 pounds per foot so you will need the pump to be able to push a minimum of 25 psi for any flow from ground level to the top of the tank. I have a firend that gets water from a spring he pumps the water ~65' up the hill to a large tank and he has right at 30 psi in his cabin.


Can I connect two wires to a single screw terminal in my HVAC system?

The schematic image you've attached is difficult to see, so I can't say for sure. Based on the wiring, I would say that the B terminal would work as C.

Since I'm not there and can't test things, I have to make some assumptions.  Based on the wiring, it looks like the one cable goes to the thermostat and another goes to the outdoor air conditioning unit. Since the red wire from the A/C cable is grouped in on the Y terminal, and the white wire from the A/C cable is on the B terminal. One can reason that the B terminal should be connected to one side of the transformer coil, while R is connected to the other.

You can test this theory by setting a multimeter (or voltmeter) to AC volts, and testing between the R and B terminals. You should read ~24 volts.

You can either connect both the white wire that's already on the B terminal, and the new C wire to the screw terminal. Or you can connect the white wire and your new wire together with a spare bit of wire, using a twist-on wire connector. Then connect the other end of the spare bit of wire under the B terminal screw.


How do I seal a leaking plughole fitting?

This basin trim piece you are referring to is usually connected to the tail piece flange with a very fine thread. If has been in place for a long time, they can be difficult to remove. You will need to insert something like needle nose pliers in the top and hold the tail piece from the bottom and unscrew it. Clean out all the old plumbers putty and replace it by making a "rope" of plumbers putty in your hand, place it around the top edge of the hole in the basin, then reinstall the trim piece into the tail piece section. Tighten it so it pushes out all the excess putty, and is tight.  Clean up the excess, return it to your can. Job done.


How do we add structurally sound faux stud for a single stud TV mount?

A bunch of ways to do this. What I would probably do myself, which is not what you are currently planning, is:

Cut a piece of plywood, probably 3/4" thick, 24" tall by ~ 20" (studs 16" apart) or ~ 28" (studs 24" apart).
Mount the plywood with 3 screws on each stud.
Paint the plywood to match the wall. It doesn't have to be perfect because it will be mostly hidden by the TV.
Mount the Kanto PS300 to the plywood.

I wouldn't necessarily recommend that for all situations, because of the need to paint the plywood. But if you are going to open up the wall to put in a stud, you are going to need to do drywall patching and then painting, so this will actually be a lot less work.

If you insist on the original plan:

Cut a hole in the drywall ~ 36" tall (24" stud + 4" on top and on bottom for the cross pieces) x ~ 16" or 24" (depending on distance between existing studs)
Screw metal brackets into the existing studs and new 2x4 pieces to span at top and bottom.
Screw metal brackets into the new 2x4 cross pieces and the new stud at top and bottom.
Patch drywall
Paint
Mount Kanto PS300


You can slow down condensation on cold water pipes by insulating them.

What?  Insulate cold pipes???

Sure, why not.  The insulation doesn't care. The insulation will act as a vapor barrier to keep humid air away from the pipe, and will greatly slow the warm-up of the pipe.   Remember, in condensing conditions, what is warming the pipe is the enthalpy of vaporization as water vapor condenses.  The water vapor gives up 2257 joules/gram or 970 BTU/lb. when it transitions from vapor to liquid, and this is what warms the pipe until it equalizes to ambient.  The insulation greatly slows this process, reducing condensation greatly.


What can I put over drywall on a garage firewall?

The Code does not restrict material installed on top of “Fire wall” materials. (Btw, the 5/8” type-x gypsum board is only required on the garage side. It’s not required on the “living space” side.)

Also, you can have “holes” in the gypsum board, including electrical outlets, electrical switches, a door if it’s fire rated, etc.

Also, the garage cannot have a door opening directly into a sleeping space.

UPDATE:

Oops...actually the Code does restrict what can be installed on walls and ceilings. They can’t have a “Flame Spread Rating” greater than 200, unless it’s less than 1/28” thick and cemented to the surface and has a flame spread rating less than paper. (See ICC R302.9). Also, they can’t have a “Smoke Development Index” greater than 450. (See ICC R302.10)


How do you open this fluorescent light fixture?

First, Are you entirely sure this is a fluorescent fixture and not an integrated LED fixture?   Because it's awfully, awfully thin for a fluorescent.   The only tubes I can imagine even having a chance of fitting are T5s (5/8" diameter).
However, fluorescent fixtures never require tools to get the tubes out.  IF this was fluorescent - and it's very much my hunch that it is not - you would push upward a little bit (1/8" or so) along one of the long edges (either one) and then slide it toward the edge, making the other side pop out, i.e.

However I wouldn't do a whole lot of pushing.  If this doesn't happen easily, the next step is to presume it's a bulbless LED, and search it for a model number or identifying marks, so you can search for that and see if it is.
What's the deal with bulbless LEDs?  Isn't that bad?  Sure, I get it. We all grew up our whole lives with every type of lightmaker - incandescent, halogen, fluorescent, HID - all having the bulb as the weak link/consumable. So it's hard to believe that with LEDs, the lightmaker is actually the most durable part.  But it is silicon electronics - and when's the last time you changed a transistor on a stereo or TV? But vacuum tube TVs and stereos required changing them all the time - to the point where historians/purists had to learn to make their own vacuum tubes!
Now, the weak points are in the electronic power supply that converts AC power into the correct current of DC for the LEDs.  Cheap components (notably capacitors), solder (RoHS lead-free solder that crystallizes; many PCB problems these days are cured by running the board through a solder reflow) and other electronics-side stuff - but not the LEDs proper. Those will outlive all of us.
Of course this is cold comfort if your fixture is kaput.  Most of us don't want to pull down LED fixtures and carefully identify the constant-current electronic driver and find another one of the same form-factor.  So it's down to replace the whole fixture - and learn the lesson that the supplier isn't very good.
Given the way our markets are being flooded with cheap junk (especially Amazon!!), this type of failure is shamefully common.  I myself have chosen to stay with real fluorescent, because a GE ballast and Sylvania tubes are safe choices.


Hot and neutral touched. Some lights no longer working

Are you sure you manipulated the breaker handle correctly? You need to turn a tripped breaker fully off before you can reset it.

If that isn't the issue, there's a weak connection somewhere in the circuit that failed due to the surge. You'll need to examine each device connection and splice for faults. Pay particular attention to "backstab" connections (rear-facing plunge clamps) on outlets and switches. They're known to fail. Use the screws with a proper wire loop instead.


Using the existing neutral as a PE grounding conductor on a NEMA 10-30 outlet

We can start with this:

As installed, the grounded conductor for your dryer receptacle is white or gray and cannot be re-identified as an equipment grounding conductor according to the National Electrical Code.

  250.119 Identification of Equipment Grounding Conductors. Unless required elsewhere in this Code, equipment grounding conductors shall be permitted to be bare, covered, or insulated. Individually covered or insulated equipment grounding conductors shall have a continuous outer finish that is either green or green with one or more yellow stripes except as permitted in this section. Conductors with insulation or individual covering that is green, green with one or more yellow stripes, or otherwise identified as permitted by this section shall not be used for ungrounded or grounded circuit conductors.

Then there is using something for which it was not intended. The Code does not allow that.

  Article 110.3(B) Installation and Use.  Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

The receptacle you have was designed and intended for the third prong to be a grounded conductor not an equipment grounding conductor.

  406.4(C) Methods of Grounding.  The equipment grounding conductor contacts of receptacles and cord connectors shall be grounded by connection to the equipment grounding conductor of the circuit supplying the receptacle or cord connector.

So, if your equipment requires grounding, which it apparently does, you cannot connect a cord connector to the grounded conductor of the circuit supplying the dryer receptacle.

There are other reasons not to do this that I don't have the inclination to list here.

Just run the correct wire and install a proper receptacle for your equipment and sleep soundly.

Good luck!


Connect Ecobee3 thermostat - no c wire but c terminal occupied

Connect the blue wire from the thermostat cable, to the C terminal in the furnace. Then connect the blue with at the thermostat, to the C terminal of the new thermostat.


Set the depth of the blade on your circular saw to be just deep enough to cut through the siding. Err on the side of slightly too shallow, and come back with a chisel, utility knife, or handsaw to finish.

If your circular saw's base plate is not long enough to sit across two planks of siding, you could fashion a jig to hold it. The jig could have a long base so it sat across 3 or 4 planks of siding. The jig just needs to be a long piece of plywood with simple stops on the 4 sides; the stops would hold the saw's base plate in place.


Can you use a motion sensor switch to control an outlet

Is it possible to use a motion sensor as the light switch?

Yes. You can buy standalone sensors designed to switch lights on and off. There are both plug-in switches and ones that you hard-wire to your light fitting.

  is there an easier way to get the LED lights to turn on automatically?

It depends. You could use a microswitch on the closet door.


Should I use remodel or new construction recessed fixtures when installing a new ceiling?

Scenario #4

I would just remove all the old drywall and use new construction fixtures. It may seem like a lot of work but all these other problems go away. Plus my "drywall guy" would throw a hissy fit trying to finish a layer over another layer with a texture. The drywall won't lay flat like it should and finishing will cost you more money or it won't look right.

Pulling down old drywall goes a lot faster than you think, especially if it is nailed instead of screwed. Once you get started large pieces can be pulled down.

One problem is the ceiling drywall is usually installed first so the wallboard is supporting it (trapping it) at the edge of the room. While pulling it down the wallboard could be damaged if it is not cut loose. Replacing it will require inserting the new ceiling drywall above the wallboard.

Good luck!


First off it kind of looks like the packing nut and associated seal that it squeezes against the valve stem is missing. You could look into whether you could locate that part off a replacement valve. The strange washer arrangement on your current valve handle suggests that it may not be the original type for this faucet. It may be that a previous owner tried to replace a broken or missing handle and removed the packing nut (dumb decision) to make it fit.

Here is a picture of a valve with the packing nut in place and a diagram that shows the valve parts and operational detail.

Replacement of the missing packing nut is the best "easy" solution. The idea you had of trying to force in teflon tape is not a workable solution.

If you are able to source an exact replacement valve then you may be able to replace the "heart" of the valve as you call it. That part of the valve is removed by using a wrench on the two flats of that are part of the place where the packing nut is supposed to screw on. The replacement valve would have presumably have a proper packing nut in place.

If you are unable to find an replacement valve to steal parts from then you will have to replace the whole valve with a new one. This of course will entail cutting out the existing unit and then prepping, fluxing and soldering in new parts with lead free solder (aka silver solder). If you have to go to that extent I would highly recommend that you replace with a ball valve instead. Make sure it still has the removable bleeder port to permit draining the line in preparation for freezing weather. The one shown below has threaded pipe connections and you would want to get one with the copper pipe solder connections. Ball valves are easier to operate, give an visible on/off indication and are way less prone to leaks like you have.


Extra unattached copper line under bathroom sink

If there's a valve, then turn it off and remove the pipe. If you're concerned the valve will leak, then shutoff the water to that line, remove the valve and cap the pipe there (or replace any T's with a straight fitting).

Leaving the pipe and capping the thin refrigerator line will be difficult and error prone, and you're still left with a valve and two places that may leak.


What kind of bulbs should I get? My bulbs does not look normal

Those are 2 or 4 pin CFL bulbs. Sorta like this:

Technically, you should handle them with care, as the contents of the tubes are toxic.

Turn off the power to the light, wear sturdy gloves, and pull the bottom part of the bulb straight out of the socket. (Straight out means the direction that the tubes were going.)

With this end in a plastic baggie, you'll be able to find an appropriate replacement at the hardware store.


The voltage conversion (if nessessary) is done inside the lamp housing that you pictured. This type of retrofit lamp is designed to fit into existing recessed cans that are designed to take a reflector bulb with a standard base. If you disconnect the orange connector and screw the base adapter into a bulb socket, a voltage meter will show 120v AC at the orange connector.
There are some cans that are designed to work with this type of bulb/bezel combo and supply the orange connector inside the can instead of a screw-in light bulb base.


What diameter pipe should I run from a septic pump up hill (3 meter head ) to my septic tank?

The pump and pipe (force main, being on the far side of the pump) size should be specified by your septic system engineering documents. While I feel similar to the commentators about pumping sewage, sometimes it's the only way (house on a lake, for instance.)

I would strongly suggest both the "two pump and alarm" method (preferably with a pump controller that uses both pumps in an alternating fashion - having a "spare" sit there while the main pump works tends to lead to having two pumps that don't work when the main one breaks) and a mounting method that permits the pump to be pulled out for service (typically the pump is on rails, and the system automatically valves off the pipe when the pump is pulled out.) They are disgusting and expensive enough to repair without setting them up in a manner that requires a pump out and someone going into the hole to fix them.


How can I lower wall cabinets after fitting drywall?

Work out the correct height the battens (studs) should be, cut the plasterboard using a sharp knife or angle grinder and neat as possible and place in the battens where you want them to be. Screw your plasterboard back onto your newly placed batten and polyfill the gaps if you care about tidyness. You can then safely attach your cupboard to the newly placed batten and the cut out will not be seen because it will be behind the cupboard. Hey Presto!

Credit: Father.


How can I remove laminate flooring from an oddly shaped hallway without destroying it?

The rule of thumb is, "last pieces down are the first and easiest to remove".
If the hallway was the last to be laid, it will be an easy pull. That would be the first that needs to pull up. Remove the shoe mold, remove the damaged flooring, you may need to remove some that is not damaged to easily remove it all. Once you see how the first few pieces come up the rest will be easy. It will only be easy to remove in a given direction only. If the room to the right was done last then the removal will need to start with a saw cut at the opening. The replacement may take a glued joint or transition strip to change the direction of the "lay" of the floor.


Bridging Neutral and ground in a Light Switch

That's actually terrible.  You bootlegged neutral and that is something you should not do anywhere.

It would have been much wiser to choose a switch that requires neutral since you do indeed have neutral in that box.  I gather at the time you bought the switch, you didn't know that.

Most likely what is happening is the switch is a smart switch which requires neutral to power its internal electronics. And either a) this is cheap Cheese junk direct shipped from Shenzhen (possibly via an Amazon Fulfillment Center) that has never received a bona-fide UL listing and is not safe, or is one of the cases where UL authorized use of the ground to serve the part of neutral.  The latter is done so the switch will work in locations that do have ground but don't have neutral.  NFPA has told them to stop approving that.

So, ironically, you have done an unauthorized bootleg of an authorized bootleg, bringing it full circle, right back to manufacturer intent.  So what's the problem?  The problem is Neutral still is not Ground.  If this neutral wire has a problem, it is a guarantee that the grounded parts of this switch (like the cover screws) will be energized at 120V.  Now we hope the UL listing was predicated on the idea that the switch can't leak enough current to kill anyone.  We hope.

My recommendation would be to remove this switch, reuse it somewhere else you have ground but not neutral (assuming it is not mail-order rubbish), and fit a "neutral required, ground not required" switch here.


Try Araldite or Milliput - both are different types of epoxy, araldite is a two-part paste, milliput is a putty, and the latter is recommended for repairing radiators, so should be plenty heat resistant. The downside to milliput is that it is not especially sticky and also has bulk, so you might struggle to make a thin, solid join. Araldite should have no such issues, but I can't vouch for its heat resistance.

edit: I have just read the remark about having to reach the screw - in which case be wary of Araldite as I have heard of plenty of references to it needing something akin to a small bomb to shift it once it's cured. If you go for this, use a tiny dot that you can easily crack with a little leverage.


Why can I not adjust the cutting depth on this router?

Ok, revised my answer

I found the instructions here and the information is on page two under "Set-up: Fixed and D-Handle Base - ADJUSTING THE DEPTH OF CUT (FIG. 1, 3)"

Occurring to this there is no lock of the black adjustment ring so it should turn somewhat freely, though it might have some resistance so not to move when you don't want it it.

It's very possible that your adjuster (piece B) is stuck. As it is, it is 'bottomed out' at max depth setting and it might have been tightened in this direction too far causing it to be stuck. If you feel save that you won't break it, turn the adjuster in the direction of the grove going away from the power head, this should be obvious. Once unstuck it should turn freely

If this doesn't work, or you don't feel comfortable trying the above, then return it as it's not working as intended.


Assemble lead sheet to be tight, but able to be disassembled

In a cross section of a sliding puzzle piece, one will see something akin to tongue and groove on all four sides of the piece. In the image below, there is a partial tongue visible, but your purposes would require full length.

If you create a carrier for the lead panel pieces by bonding plywood (drywall is not wear resistant) to the lead and have the plywood extend on two adjacent sides and have the lead extend on the other two, when fitted together, the edges of the lead sheet will make contact. I suggest that having the lead extend without a carrier of its own is contra-indicated, as lead is also not wear resistant and could be more easily damaged when being moved. You would likely want a four layer sandwich.


Proper fasteners for Post/Beam/Joist intersection

I agree with @JimStewart , notching can be dangerous. Go to your local lumberyard and order a Simpson Strong-Tie column cap similar to this one:

https://www.strongtie.com/boltedcolumncaps_columncaps/eccl-ccc-cct_productgroup_wcc/p/eccl.ccc.cct

You can order them for 3-2x10 built-up beams on 6x6 posts with 2-2x8 beams joining the 3-2x10 beam. Also, you can order a corner connector.


New Central Air Install: choosing single-stage vs dual-stage condensers

2 stage equipment is for comfort, not economy. You probably won't make that extra cost back if used 2 months a year and your house leaks AT ALL. (high SEER units are useless in an improperly insulated house) Reliability is doubled in that half the system can be broke and it will still work. Heating in your area is more important I would think, spend that money on an ECM (variable speed) furnace with a modulating gas valve. If they are the same SEER then there is no operating cost difference (right guys?). A 3 ton will just run less often and cost more to do so than a 2 ton. If you want to save money, thermal scan your house and fix those issues. Unless your rich and a green freak, I see no benefit to dual stage systems less than ~10 tons. The second stage is for those months that your first stage can't handle. In your situation it sounds like it would either always run both or never need the second.

ECM's pay for themselves in about 3 years, MGV's 10 or so depending on usage. 18 SEER will never pay for it self unless your house has an astronomical R value.

Quote from HVAC TALK

  2 Stage is for COMFORT.

  Some people may save some money, from the longer run in first stage because they won't feel that sudden coolness from the short on time that a single stage has at the mild and mid range winter temps.
  Meaning they don't set the stat as high as they did with their old unit.(comparing 2 stage 90% to single stage 90%) So it looks like the low fire is saving them a lot of money by being more efficient, when its really because they have their stat set lower.

  Same with 2 stage A/C. They may set their stat 1 or 2 degrees higher. So they save because they are more comfortable at a higher temp. Which of course, maintaining a higher temp, uses less electric.

  Most 2 stage units going in are replacing older lower efficiency single stage units. Moving up from a 80% to a 90%, or 9 SEER to a 15 SEER, so they see the overall savings. And rave about 2 stage savings.
  Contractors then repeat how much a 2 stage system saved that person.

  So its just repeating observations made, without a control, to check it to.

  In your case, (not to take money from a contractor, but), I'd just set the lock out lower, and see how it does this winter.

  Keep the money you were going to spend on a new system in the bank, and let it make some interest.

http://hvac-talk.com/vbb/showthread.php?178756-2-stage-furnace-not-more-efficient-than-1-stage/page2

This guy "Beenthere" seams to really know his stuff.


Proper machine tool for sanding metal frame

You do not need to strip all the existing paint off, though you can fairly easily with a chemical paint stripper if you want to.

You need only to remove the shine from the existing paint; what I call de-glossing, to prepare it for a new paint coat. You should be able to use the 180 paper to accomplish this, but utilizing successively finer grit paper will incrementally improve the look (smoothness, shine) of the new paint.


I'd be inclined to either: fit another soap holder; remove the offending tiles and replace; fill the holes with grout, making sure it does more than plug the surface.

With idea 1, put silicone in the holes first, then the screw plug (deeper than the tile, please!) and screw holder on, with a touch of silicone to finish.

With idea 2, there's always a chance you can't get tiles to match, but if yiu can, it's the best option.

With idea 3, putting enough grout to seal the hole won't be difficult, but there will always be two blemishes on the tiles that won't go away.


Can I use diaphragm accumulators to maintain consistent water pressure?

Normal domestic water diaphragm accumulators (usually bladder accumulators are used) would not be feasible as they are used with a pump that cuts off when max tank pressure is reached. When you say "use them as a water source" please give an idea of estimated capacity needed at what pressure.  Perhaps you should be using a simple raised atmospheric accumulator (water tower) that relies on gravity to supply pressure when your "high pressure water" is not available. 8 to 10 meters height should give enough usable pressure, higher = more pressure.


Do travel voltage transformers really not have grounding?

All this stuff is cheap Cheese junk
You describe a genre of travel transformers, not just a specific one... but who's kidding who?  The "genre" you're talking about is "the infinite array of products sold on Amazon" and other online/mail-order sites.  Your underlying assumption is that Amazon is a professional and reliable supplier of goods, comparable to walk-in big-box stores like Home Depot.
Actually, that assumption is flat wrong, thanks to Amazon Marketplace.  For business reasons, Amazon chose to open their retail-sales website to any seller - ANY seller, very much like you expect from eBay.  Further, they opened up their warehousing and delivery systems as well, so eBay-tier absolute junk is sitting on warehouse shelves right next to Amazon's own stock (and sometimes commingled with it), and ships with Prime.  Of course, the "Prime shipping" is very prominently marked, but this is more subtle.

The various governments certainly have processes in place to protect the supply of consumer goods.  The problem is, direct mail does an end-run around those processes.  Items sold at retail in competent, professionally managed walk-up retail stores are generally protected - so Home Depot, Wickes, etc. should be reliable supply, provided you see an NRTL stamp.
Even the ever-counterfeited CE mark becomes reliable in a competent EU retail store supplied by EU manufacturers or industrial EU importers... because they are within the reach of EU's enforcement agencies.
So my strongest advice is limit yourself to supply chains subject to that government scrutiny - competent retail stores (e.g. not your local flea market/junque shoppe).
Oh heck no - UL would never approve that.
Your intuition is spot on: "Bull feathers!"
Obviously, a device should not offer a grounded socket if it doesn't have any source to obtain ground from.  (this might be allowable if GFCI protection was present, but it's not).
In the US, we have a very solid system for approving consumer electronics.  Underwriter's Laboratories (UL) writes a "White Book" of product safety standards every product must meet, then a manufacturer sends prototype devices to UL, and they teardown the device and torture-test it for compliance to the White Book. (US OSHA maintains a list of "Nationally Recognized Testing Labs" also qualified to do the testing, such as CSA or ETL.).
Generally, any electronics seen in a retail store has a UL, CSA, ETL or other NRTL listing with file number.
Meanwhile Europe has the CE mark, in which domestic manufacturers self-certify their goods (this can include goods they import into their own warehouses). Difference from direct mail being, the manufacturers have something to lose; something for enforcement to threaten.
But you want a bargain.  I'm not so worried about this bargain, which you can readily see is a ripoff and Darwin award... I'm worried about the all the other bargains whose danger is not so obvious.
Simply turn off dodgy supply channels.
I get the allure of online shopping, and especially Amazon Prime "since you prepaid for shipping". But the fact is, some areas (especially consumer electronics) are so awash in this crud that buying from many sites is simply futile.  There's no answer but to stop trying.
I certainly believe COVID-19 is real, and I see the case for online shopping. However, my recommendation is to shop at the websites of bricks-and-mortar stores such as Home Depot, Wickes, Redoute, etc.  While these sometimes intermix Amazon or eBay results (looking at you, Walmart and Sears)... the items on the website are the items they sell in the stores, which are UL-approved, legal and safe.   As far as free shipping, I'd point out that most of them cheerfully do curbside.


I don't see why not.  Just keep in mind that a fresh screw hole is going to give you a much tighter connection that going into one that has already had threads cut through the wood.  If you're worried about the holding strength, just go up one screw size and think of the old one as a pilot hole.


How to attach closet flange to sub floor

I would not leave a gap, and use screws long enough to reach through the plywood through the backer board. Make sure the flange is well supported or you'll have problems with it down the road if not immediately.

Maybe an even better solution would be to have plywood of the right thickness span the gap between the subfloor and the flange, and still use longer screws that will reach the subfloor. Cement backer board tends to be weak at its edges and may not provide the support the flange needs. Plywood on the other hand is very strong at its edges and should hold up marvelously. This small piece of plywood can be kept inside the area that the toilet bowl covers so you won't have to put tiles over it or anything. You might want some plastic shims on hand for the job too, in case the plywood and flange don't meet nicely. Good luck.


How to drill a groove to the side of a plywood board?

Just clamp a scrap of plywood to the top of the board and use a hole saw to cut through both boards.


60 amp breaker feeding a subpanel with breakers totaling 100 amps

You really cannot go off breaker sizes for ac units. The reason I say this is because this is one place code allows larger breakers than the wiring can support. How can code allow larger breakers than the wiring can support? It is because of the starting current, this can and many times is 5x the running value of the unit (with conventional ac systems) on a newer system with a variable frequency drive they don’t have as high starting currents and vary the speed to save $.

Based on what you have I would bet you could use this panel for both but would want to look at the name plate fro each unit. If it was close and I did hook it up I would then want to test with both systems running at 100% and actually measure the load on the system. I use a mastech ms2180 it is an inexpensive ac/dc amp clamp meter with voltage, ohms, diode and capacitance measuring abilities I think it will run for 10 minutes recording peak values and this can help you decide if the feeder is large enough for your loads. If you add up the breakers it is common to have a much higher total for several reasons.
The breakers on the even numbered slots are on 1 leg and the breakers on the odd slots are on the other leg, if all single pole breakers 60 + 60 = 120 so to get a better idea you would just add the breakers on each leg. Now just adding 1 leg the total can still be over the total for several more reasons including a 20% safety margin and usually the total load on a circuit is less than 80% of the breaker size except on startup. I have found every home I check many are running less than 50% of the main breaker size many in the 30% range because of load diversity.

There is a fairly large safety factor built into wiring standards and the short peak period of both units do start at the same time will probably still be ok because breakers are inverse time rated, this means they can supply current above their rated value for a short time, most breakers do not immediately trip at their set value but 10 seconds or more after reaching this value based on their trip curves. The higher the current the faster they trip so your actual load could be 150 amps for a few seconds with out tripping the 60 amp breaker since it is only a few seconds the wiring doesn’t have time to heat up and damage the insulation this is the key. When everything is up to speed and cycling normally we like the load to be at 80% .

This got a bit long but to provide an example I just added a new branch circuit to a panel that by the total breaker value was 320a even after adding this new load (30 amp double pole) my measured draw for 30 days did not exceed 70% (larger measurement system used) this measurement shows I could safely add another double pole 15 amps to that 150 amp panel (grand total of 410 single pole value)  and still be fine.


In my opinion yes, you need to eliminate the dips. Anything that will be spanned over a low spot by the Dricore will move under foot. It is after all only a high grade OSB and the T&G joints will eventually fail somewhere over time.

The whole floor does not have to be level, just on the same plane.

On a concrete floor, a laser level will drive you crazy, do not do that to yourself. Technically, it needs to be flat, ideally it should be level, but level is not critical. I see eyes rolling now.... A string line will give you a good idea of what is in plane, not relying on it needing to be level. I refer to a level as a straight edge only, not using the bubble to determine level. Usually a level is always straight, therefore a good candidate for checking flatness over a given area. It is a lot of "hands and knees work". Scoot the level all over the floor to see how the floor plane is in any 4 ft span. This will help locate the high spots. Situate the level or straight edge over 2 high spots, anything over a 1/16" needs shimmed.


Put an expansion joint in the same location as the crack or remove the drywall and replace it but change the layout so there isn't a seam there. It's common to get cracks at doors like this, so when drywalling the professionals try not to put seams that close to either end of a door for that reason.

You can retape this as is with paper or mesh tape and joint compound, but the crack always comes back. If you go this route, trying not to slam this door will help the repair last longer.


Can I combine elements in my three-phase oven and feed them from separate mains?

Wired for Europe it is probably wired for 3-phase "wye" (like a Y).  Each leg of the Y has a triplet of heating elements, with all of them tied together "in the middle" at neutral.  The neutral may not be properly wired back to the neutral wire.

Where they all join in the middle for neutral, that would have to be eliminated.  Each triplet must return its neutral to the same branch it gets its hot from, and the neutrals cannot mix.  You could keep the triplet of elements together though.  So each triplet would need to be isolated from the other neutrals.

It could be run on less than 3 circuits, but would not get as hot / would take longer to reach operating temperature.

A commercial machine would be built for this kind of reconfiguration; it is common.

Your bigger problem is the lack of certification-agency listing on  the machine.  If there's an accident, your insurance company may not pay out, and the authorities could hold you liable.


How to repair chipped tile edges on an external facing corner?

Yeah metal trim is probably the best way. if you're cheap there's aluminium angle that can be glued on using bathroom silicone caulk.

For a slightly better look get a strip of stainless-steel bent 95 degrees along the length (so the angle is 85 degrees). and glue that on in the same way.


Multiple GFCI receptacles, Fridge is tripping one it ins't plugged into

You should avoid plugging fridges into GFCIs any which way you can.  Refrigerators are the exact opposite of the use-case for GFCIs.*

However, the latest version of Code requires GFCI devices in garages.  It's a pity; old installations are "grandfathered" and you are not required to retrofit GFCI.  We are recommending that you use any means possible/necessary, to arrange your wiring so the refrigerator/freezer is on a "grandfathered" old outlet not on GFCI, and this outlet is a single outlet labeled "Freezer only".

You might think "Oh, I'll hit Habitat for Humanity Store and find some old, ugly, painted-on boxes, receptacles, covers, conduit and/or cable, and some rusty screws to make the installation look old".  I couldn't possibly advise such a thing.

Now if "3 GFCIs on one circuit" is true, this guy's either dumb, or so smart he looks dumb.  Generally, fridges notwithstanding, one GFCI device can protect the whole circuit.  There are reasons to put multiple GFCIs on a circuit (like a fridge at the 3rd receptacle), but pressing "test" on one GFCI should never knock power out to another GFCI.  If so, the second one is useless and should be changed to a plain receptacle.  The spare GFCI can then be used to protect another circuit.

* Fridges are 3-prong grounded, metal chassis, all the electrical gear is in the bottom back where it is wildly inaccessible, you are unlikely to drip hollandaise sauce into it, and you probably won't drop it in the sink. They are also expensive (not cheap throwaway countertop appliances) and contain a cyclically operated  large motor that is prone to minor ground faults, which are factors that are anti-GFCI.  Further, there's another life-safety issue: food spoilage.  So you have "dueling safety features", like a low-oil-level shutoff on a fire pump.  Do not sacrifice the warehouse to save the fire pump.


How can I repair water damage under the kitchen sink?

There is a sub-panel between the bottom of the cabinet and the
actual floor. Measure the board so you can create a new one (You can
also get a piece of cardboard to create a template to cut from -
works great with a cabinet with many angles.). To remove it (since
it's particle board) you can just break it out with a hammer. **Be
careful not to damage the spacer board that helps support the middle
of the panel. If you damage it or if it's in bad shape, you'll need
to cut a new piece to replace it.
When you measure and cut the new board, you will most likely need to
cut it half to get it under the sink. You'll need to figure this out
and make sure to add a quarter inch (width of the saw blade) to the
width of the new board to compensate for the cut in the middle.
Again, you might need to put in a space board in the center for
added support. You'll also need consider where the pipes come in which might be from the floor from the wall. If from the wall, it will of course be easier.
Once the new board is in, you can use the Sintra panels. Or get a
piece of linoleum to cover it so you can help prevent water under
the sink as well as hide the center cut (Or any bad cuts you might
have made in the process). You could also get the 12"x12" adhesive
panels.

Tools

drill,
skill saw or table saw,
possibly a jig-saw
tape measure
safety glasses.

Hardware

screws
maybe nails


Walls running parallel with joists are almost never load bearing. Your pictures make it seem it is running parallel. I personally, from the information you have provided, say it's safe to knock that wall out from a roof truss/joist support perspective.


Can I use DOCSIS 3.0 to connect to my LAN over coax?

You need an ethernet-over-coax device for RG-6 cable.

A slightly surprising source of these is CCTV suppliers, as there is a lot of analogue CCTV wiring out there, and people want to upgrade to higher resolution IP CCTV, without running new cable. Therefore, converters to run Ethernet over Coax are available.

Example

  VHW-HW    HIGHWIRE Ethernet over coax converter (2 required per link)
  100BaseT up to 350m (1150ft) full-rate over RG-6

https://www.veracityglobal.com/products/ethernet-over-coax-devices/highwire.aspx

One supplier

http://www.eaccu-tech.com/by-vendor/vhw-hw-veracity/

There is also a possible hack solution - connect wifi antennae connectors directly to the co-ax cable.

  There are some problems with this plan. WiFi is 50 Ohms, TV coax cable
  is 75 Ohms. Only one MIMO channel will be available meaning the
  maximum theoretical bandwidth will be 433 Mbps. WiFi is also at much
  higher frequencies than what coax is designed for.

  With two WiFi antenna to coax adapters, [Tobias] simply connected the
  coax directly to a router set up to bridge Ethernet over WiFi. The
  entire thing worked, although testing showed it was only getting about
  60 Mbps of throughput.

https://hackaday.com/2018/10/19/wired-wireless-over-coax/


How do I remove the old plastic dishwasher water supply line connection near the shut off valve?

There are many ways to skin this cat. But probably the easiest one would be to cut the plastic pipe so that there is no water in it. The reason you want to remove the water is so that you can then use a hair dryer to get the plastic warm and soft. Use two pliers- one to brace the copper valve and the other to twist the plastic pipe or connector off.

If that's not working, a pipe sander or dremel tool (with a cut off wheel) could probably chew through that connector pretty quickly, but I suppose you could also try using a box cutter to cut into the connector (which looks like it will be easy if it's warm and soft). But just be careful to not cut too deeply or you might damage some copper or brass threads. You should cut most of the way through the connector and then maybe use a small flat head screw driver to pry the connector loose.