What do I need to do to restore a wooden entry door?

We just use good ol' bondo to fill missing pieces in wood. In the cabinets I did last weekend, several of the doors had an inch worth of corner rebuilt from bondo.

The other tool that helped us that weekend was a profile detail sander; specifically the octosander by Skil.

You can use the same spray gun you would use for cars, but you might need a larger diameter tip/needle combo. With my gun, I need a 1.7mm tip for oil based enamel and a 2.5 for water based.

Edit to add our process:

sand with an orbital sander and profile sander using 60 to 120 grit until the surface no longer has brush marks. It's OK if some of the original paint is still present. This ended up exposing some raw wood. Don't be afraid to press down hard on the sander at this point -- you're going for removal, not smoothness.
Clean areas that require patching or bondo using a stiff wire brush to remove any rotten or loose wood. Mix and apply bondo, keeping in mind that the set time of bondo is typically very small and that you want to apply it in it's most liquid state for it to bond well with the wood. Do not let it partially harden as you're applying it; stop and mix a new batch. Sand bondo after 45 minutes of hardening using a wood block with sandpaper wrapped around it so that you get a surface that is smooth with the rest of the door.
Wipe down to remove sawdust and paint debris, wait for it to dry. Apply a thick coat of primer across the entire surface. Wait for it to cure (12 hours).
Sand any areas that show as high LIGHTLY with 120 grit. This will probably include the bondoed area and any area around where raw wood was exposed. Sand more heavily with 120 grit in areas where the primer was attempting to fill in a crack.
Wipe down, wait to dry, Prime again, lighter this time.
Sand lightly with 220 grit until the surface is as smooth as a baby's bottom. You want to make sure you remove any signs of any orange peel or other imperfections in the primer coat, because they will show right through to the finish coat.
Apply finish coat smoothly and evenly. If you're in a climate like mine (hot and humid), move the door indoors to cure for > 24 hours before attempting to mount and close it.

Dad has always used exterior-grade Alkyd (Oil) based finishes on wood doors. Due to VOC restrictions, many of the finishes he used are no longer available, and the newer low-VOC formulations are prone to chalking. Our paint store, who I trust implicitly, now recommends that we use an alkyd primer and then coat with an exterior acrylic.


Monthly Costs

You can evaluate the electricity cost for a security camera setup yourself. Take a look at the cameras that you are interested in and note how much power each camera consumes. This may be a direct rating of Watts or it could specify operating voltage and current. You can compute the Watts from the voltage times the current. So say that the cameras are rated at 12VDC and the current for each camera is 0.25A (equivalent to 250mA). So 12V x 0.25A = 3Watts per camera.

Next you have to consider a power supply unit that would provide the 12VDC for the cameras from mains power. These units are not 100% efficient and consume some power as well. Typical efficiency may be say 75%. So if you happened to deploy 10 cameras at 3W each that would be a total of 30W load on this power supply. The 75% efficiency would mean that the supply will require 30W / 0.75 = 40W from the mains power line.

Electricity is typically sold in units of KWatt-Hours (i.e. 1000W usage for 1 hour). Electricity cost will vary a lot from region to region so for sake of discussion lets make an estimate of 0.25USD per each KWatt-Hour used. (This will be high for some many regions in the USA but for sake of discussion let us guess high).

Let us base cost of operating cameras on a 30day month. At 24 hours per day that totals out to 24 x 30 = 720 hours per month. The 40W that we computed for the AC line power is same as 0.040KWatt. The total cost of operating cameras day and night for the month will be 0.04 x 720 x 0.25 = 7.20USD per month.

You can follow this process to come to a more realistic calculation based upon your actual electricity cost, the number of cameras you deploy, number of hours of operation per day and the actual Watts of power used by each camera. The numbers I chose above are just seat of the pants values chosen to illustrate the calculation. Your actual monthly cost may be quite a bit lower or could be higher if you chose to use many many power hungry cameras.

Installation

There are many schemes used to install security cameras. Whether any particular scheme requires you to make holes in your house will depend entirely of things that only you can determine such as:

Type of cameras that you choose to purchase
Method of powering the cameras (battery, DC power wiring or Powered through signalling cable)
How signals get from camera to monitoring system (Ethernet, WiFi, coax video)
Your concerns for camera and wiring hiding versus visibility
Your capabilities and tool resources to try to do a DIY install


If it's structural (the tread/risers are supported by it), it's called a stringer.

If it's not structural, it's called skirting (or simply a skirt).

  Source (PDF)


Is it possible (/advisable) to install foreign plug sockets in your home?

I do not recommend it. It would most likely be against the electrical code in your region. My experience with those types of receptacles is that they do not grip onto your plugs very well and they can pull out or even fall out from the weight of the cord.

Just get a couple sets of appropriate adapters and keep them in a drawer in the guest room.


Is there software or a web site that lets me upload a photo and visualize changes to a room?

This isn't exactly what you're looking for, but I would suggest that you try Autodesk Homestyler.

An example in design mode

And a feature that renders your design into almost life like pictures!


No do not do this! The cold air return of the furnace goes into the house. You cannot vent a portable a/c into the space being cooled. It may seem to work for a while but will inject more heat into the space than the a/c removes.


Is it against code to run electric Line in cpvc out of breaker panel and into the ground?

You have to use conduit listed and labeled for electrical use. So if you're thinking about using plumbing pipe, forget about it.

Since the conduit will be underground, it's considered a wet location. That means you'll have to  use wires that are allowed in wet locations. THWN is commonly used for this, though is likely advertised as THHN/THWN or THWN-2, or something similar.

Wherever you enter/exit the ground, you'll want to use an expansion fitting. This allows the conduit to expand and contract, as well as allowing the ground to heave and depress as soil conditions change.


R-value for insulating a vaulted ceiling?

The numbers I found for your area are actually R30-R60, so more than R30 would be ideal as air conditioning is expensive and the one-time cost of better insulation can easily pay for itself.
How deep are your rafters?
R values of common materials can be found in this chart from greenbuildermedia.com:

To this chart, I'll just add that if you're wealthy there is also Aerogel to consider, with an R-value of R-20 per inch.  It's still insanely expensive so the time needed for it to pay for itself might exceed the life of a normal building.
Thanks to a correction from Lee Sam, according to (See ICC R806.1.2 in the Residential Code) you need a 1" air gap between insulation and sheathing so the following numbers are adjusted accordingly:
Say you have a 6 inch deep rafter, you divide the total R-value you need by 5 inches.  The result shows for 30 to 60 R-value you need a material with an R-Value per inch of 6-12, so you'd need Polyurethane spray foam or Foil-faced batts of Polyisocyanurate.  You would actually need aerogel if you wanted to hit a total R-value of 60.
If you have an 8 inch rafter you need an R-Value of 4.28 to 8.57 per inch depth.
For a 10 inch rafter you need an R-Value of 3.33 to 6.66 per inch depth.
For a 12 inch rafter you need an R-Value of 2.72 to 5.45 per inch depth, so anything other than blown fiberglass or Vermiculite will do the trick.  11 inches of Aerogel batting from a reputable source will give you an R-value of 220 at a cost of $1031.25 per square foot.
If cost is an issue to you, still think about the long term cost of AC since you live in Texas, but use these numbers to check which of the materials that work are available to you.  Calculate the cost per R-Value per square foot one inch depth for each material and then look at the total R value you get if you completely fill the space with each material.  It might be worth spending 10-50% more per volume on a material if it lets you increase the total R value.


Replaced light fixture, now 3 way switch doesn’t work

Sometimes a NM cable is not fastened down along its length, either because it was fished through an existing wall (old work) or because the builder just laid it between the attic joists (poor work).

If the NM cable that you moved is not thoroughly fastened down, and if the strain relief at the other end is inadequate, then you probably moved the wires or wire nuts around inside the box at the other end and knocked one of the travelers off its terminal.


I have an exterior water tap for a garden hose that needs new caulking

The best I can suggest is remove that old wood,it may attract insects as well,I used closed cell spray foam to seal my numerous entry holes,and the closed cell should help stabilize the pipe.If you have acess you could stabilize it with a bracket or hanger if its in the crawl space or basement.Good luck


What type of rubber pipe is used for this particular installation of hydronic radiant in-floor heating, and is it reliable?

It looks like Onix tubing, but installed incorrectly. If it is Onix then it does have an O2 barrier. It should be installed with special reusable crimp rings

If it is Onix, the material is very reliable (when installed correctly).


How can I test the integrity of my neutral wire?

The problem could be either (or both) a marginal neutral wire and/or an unusual load on the circuit.

To narrow it down, I would place an oscilloscope at a representative point on the circuit—such as an outlet beyond the lighting.  With a dual channel scope, probe the hot and neutral wires with the scope grounded to the circuit ground at the same point.  That way the scope will see the same conditions as the lighting.

Experiment with various sweep frequencies at a time the lights are flickering.  On the hot wire, square waves would tend to indicate an intermittent wire connection.  Spikes with harmonics in the 100 kHz to 5 MHz range would indicate arcing which could be a almost-broken wire or loose connection.

A significant signal (> 0.5 volts) on the neutral probably means the wire is not well connected.  With an assistant, see if wiggling outlets and switches affects the signal.  Or simply shut off power and open every outlet and switch and tighten the wire connections.  Also, open the breaker box and firmly screw down every neutral and ground wire in the terminal strips.  If that doesn't clean up the neutral, unplug/turn-off everything else from the circuit to see if there is any effect.  1980s-era switching power supplies (such as in computers) could cause this problem.

Follow up with a comment about any findings so someone (maybe me) can help pinpoint what they mean.


How do I prevent harmonic resonance hum in PVC vent of newly installed hot water heater?

Couple options come to mind:

Change the fan.
Change the fan speed.
Change the fan connection to the vent.
Dampen the vent.
Change the size or length of the vent.

If you can't or don't want to change the fan, then try dampening the vent by clamping it somewhere to the building structure and possibly adding some padding or pipe insulation where it makes those connections. This changes the resonance length without changing the actual length of the pipe.

If dampening the vent doesn't work, then you can change the length of the vent. You mention that you can't make it shorter, but perhaps you can make it longer, or larger. Check the manufacturers requirements on the maximum length, number of elbows, minimum size, and required slope before making any changes like this.


How would one extract a brick chimney embedded in the middle of a house?

We removed an old brick chimney to install a modern (well, 1970's modern - stainless steel is more common these days in your better chimneys) block and tile chimney by simply hammering and removing bricks. If you do it top down it's "apparently more tedious" but actually less time overall than anything involving "knocking it down" and then clearing up the mess, when it's inside an occupied, normally clean house. A wide mason's chisel may help. Bricks are actually pretty easy to get apart when you learn how, and that won't take long if you pay attention to what works on the first few layers.

Incidentally, if you drop the bricks down the chimney they pile up in short order and become a relative pain to remove. Take it from a former teenager who thought that was a great way to get rid of them until we hit the pile coming up as we were tearing down.


Installing grounded light fixture on box with no ground conductor

There's a few options.
No grounding conductor
If there's no grounding conductor at all, there's a few things you can do.
Install a grounding conductor
Obviously, you could install a grounding conductor for the circuit.
Share a grounding conductor
Code allows you to share a grounding conductor from another circuit, as long as the grounding conductor is properly sized.
GFCI protected
If you're replacing a fixture, you don't need a ground if the outlet is GFCI protected.

National Electrical Code 2014
Chapter 4 Equipment for General Use
Article 410 Luminaires, Lampholders, and Lamps
410.44 Methods of Grounding. Luminaires and equipment shall be mechanically connected to an equipment grounding conductor as specified in 250.118 and sized in accordance with 250.122.
Exception No. 3: Where no equipment grounding conductor exists at the outlet, replacement luminaires that are GFCI protected shall not be required to be connected to an equipment grounding conductor.

Grounding via conduit or cable covering or ground in box
At times, metallic boxes are grounded using metallic conduit, or the outer covering and/or internal bonding strip of armored cable. If this is the case, then the box may actually be grounded.
There's also a chance that there's a grounding conductor stuffed in the back of the box.
Extend the grounding conductor
If the box is grounded, you can simply connect a grounding conductor to the box. If  there's a grounding conductor stuffed in the box, you can simply connect to it.


What is the appropriate fitting to connect an armored cable to this stand-alone receptacle product?

That is not the right clamp
The clamp/fitting you have is a two-screw type clamp designed solely for use with nonmetallic-sheathed cables (NM, UF, and perhaps SEU/SER).  Instead, you need an armored-cable fitting that fits a ¾" KO and is of the right size to accept the outside diameter of your cable; there are several styles available, but the one you're most likely to find at a hardware or big-box store looks like the Arlington Industries 8402 depicted below:


Help me fix a gap between tile and baseboard!

You have a 3/4" gap and a 1 1/2" gap, and clearly the larger gap is too wide to be covered by a baseboard alone.

What I might try to do is see if you can get a standard baseboard against the wall which will give you about 3/4", then I would put quarter round right after that against the baseboard.

The 1.5" gap will be hidden, but you might need to cut a 3/4" wide strip of wood so the quarter round has something to sit on.  It should be roughly the same height of the tile so the edge of the quarter round will be just covering the edge of the tile.  If there any more gaps at this point I would probably get some white paintable caulk and go around the base of the quarter round.

I like this approach because I think a little quarter round around the baseboards of your room can be quite aesthetically pleasing and make a simple boring looking baseboard look even nicer.


A mains switch that can stay in the middle state is a bad quality switch.
If there's a proper toggle mechanism inside the switch it will be in either on or off state. An in-between state (contacts just (not) touching) can cause arcing, this will burn the contacts of the switch. What happens to the load depends on the load. An ordinary tungsten lightbulb or heating element (toaster, oven, water cooker) usually don't care. Anything with a something inductive inside like motors, fluorescent tubes (they have an inductive ballast) and anything with electronics inside will not like this either. Eventually they will break.

Just get good quality switches and then it should not be a problem.


Is it safe to plug christmas lights into a power strip or surge protector that's connected to an extension cord?

First off, power strips are not supposed to be plugged into extension cords. Any extension cords you use for Christmas lights must/should be rated for outdoor use. Any outdoor outlets you use have to be GFCI protected outlets. So, get an outdoor power strip with a long cord similar to the one shown below. Plug it into a GFCI protected outlet and stake it into the ground. From there, you can run outdoor rated extension cords to various locations. Most light strings are not three wire but it's OK to plug them into a three prong extension cord. I usually tape the plug to prevent moisture from getting in and tripping the GFCI.


Merging water softener drain line to water heater relief valve drain line

The down pipe from your water heater relief valve should not be plumbed into a drain.  the output end may be hovering over a floor drain but not hard plumbed to drain lines.  If the relief blows off due to high pressure (possibly steam) it could rupture a hard plumbed drain line.

There are two drain lines from a water softener; one over-flo from the brine tank and one off the control valve.  The over-flo line could go to the same place as the heater relief output.  The line from the control valve will have a significant pressure while the softener is in recharge or backwash modes and should be hard plumbed through a check valve to your drain piping to sewer or septic.


The high and low settings of the lights on your range hood are most likely not controlled by standard semiconductor triac dimming technology. Such technology is typically used where continuously variable brightness control is desired.

In the case of your range hood the high setting applies the full AC waveform of the mains voltage across the light bulb. For the low setting the light bulb is typically placed in series with a diode that cuts out half of the AC voltage waveform thus operating the light bulb at half the typical average voltage.

The graphs below show the difference of the AC voltage waveforms for the two cases.

The high setting allows the bulbs to be energized for the AC line voltage being first positive and then negative during its 60Hz cycle (16.66 msec total per cycle). The low setting with the diode only allows one polarity of the AC voltage to be applied across the bulbs.

(Note that in the above pictures the AC waveforms show that the voltage attained by the sine wave at its peak is about 170 volts. The typical 120VAC we are familiar with in our homes is an average value that would deliver an equivalent amount of total energy as the sine wave if the voltage waveform was a flat line at 120 volts.)

Typical incandescent light bulbs that give off light by heating a filament to white hot temperatures have a thermal response time that is much longer than the 16.66msec period of the AC waveform. This averages out the light emission of the light bulb to the extent that we do not see flickering when viewing the light bulb.

LED lights on the other hand are a semiconductor component and are able to respond to changes in applied voltage much more quickly. So quickly in fact that most LED bulbs that are designed to run right from the mains power line have to have internal circuitry that converts the AC line voltage into a DC voltage to operate the LED. The reason that you will see flickering with the LED bulbs on the low setting is that the AC to DC converter circuit built into the LED bulb is not designed to handle the case where the AC voltage disappears for half of each cycle and is thus turning on and off (at least partially) at the AC line frequency rate.

Could LED bulbs be designed to work without flicker at a "low" setting like this?

The answer is that yes they could be and such LED bulbs may very well be available. However such circuits cost a bit more to build and may take more space in the base of the bulb.


How do I replace switch/outlet to GFCI/switch combination?

My suspicion: an open ground

This is based on two factors:

Your three-lamp tester is unable to trip the GFCI, but the GFCI tests OK.  This is because the internal TEST button doesn't rely on the ground (it goes load-hot to line-neutral or vice versa), but the three-lamp tester's TEST button is connected hot-to-ground, and thus requires a solid ground connection to work.
Pushing the TEST button on your tester yields a "hot/neutral reverse" indication despite it testing correctly initially -- the "correct" indication is due to capacitive coupling between neutral and ground providing a current path "home" for the current through the right-hand lamp.

I'd check to make sure the green wire is securely connected to the box in your case; if it is, then the problem's upstream somewhere as it appears this receptacle was wired using conduit (note the locknut and fitting at the bottom of the box).  If you can't find it still -- call in an electrician, as they should have better tools (such as an earth fault analyzer/loop impedance tester) that can be applied to the problem.


Are the sprinkler heads attached to the underside of the supply line? The proper way to design this system would be to have the sprinkler attach to the top of the supply line instead of the bottom.

With the sprinkler heads attached above the supply line, the most excess water that would be drained is the water in the short pipe above the sprinkler head.


So it looks like you have tile all the way down, and a fiberglass pan. Even if the door was caulked properly, it's entirely possible that the water is wicking through the grout.

Make sure the entire door is caulked
Make sure the place where the tile meets the fiberglass is caulked as well

If either of these are not caulked, go buy a siliconized latex caulk and caulk it again yourself (make SURE it's dry first)


How can I completely shut off / inert my home alarm system?

Note that it would be dangerous to go without some compliant smoke alarm system - in the comments, @Anthony X indicates there are other smoke detectors / smoke alarms present.

I'd say it's 99%+ that the battery and power supply are the only two sources for the system and if you unplug them it will be down.  You might as well unplug the phone line connection on the right too.

Be sure to test the remaining smoke alarms, and make sure the system alarms as it should, and that there are still working smoke alarms in all the necessary areas.  At a minimum, you want one in every bedroom, and in the hallways outside of the bedromms, and make sure there's one on every floor of the house - including the basement.

I would probably check out all the existing smoke detectors and replace them with something current.  Smoke alarms don't last forever, I'd rest easier if I knew what I have and had confidence that it works as it should.


this is called a knee brace
You mean the span not the bearing width. Assuming the brace to be fully effective, the effective span is less than the span between the knee braces. The reason is too complected to explain in detail here. For design, you could be conservative and just use the distance between the braces
I usually suggest lag screws. The screws will be in shear, not withdrawal, so the length only needs to be long enough to get through the brace and into the main member a few inches

This isn't a very good solution. You'll create bending in your trimmer and king stud that will reduce their design strength. Knee braces generally aren't used to reduce the span, they are for lateral (sideways) strength so that it doesn't fall over. Think about a gazebo

Your best solution is to replace the header with a stronger one. It can be of the same(ish) size and therefore not reducing the opening under it. Good options include glue laminated beam and manufactured lumber such as LSL, LVL and PSL.


Subpanel installation breaker size: is it big enough?

Using a 60 amp breaker is fine. The breaker serving a panel does not have to be larger than the total of the breakers in the panel; it has to be appropriately sized for the load. I doubt you'll be using the steam generator, compressor and pressure washer at the same time, so you'll be fine.


To elaborate on what Hari said, it's important to note that the most common kind of trap is for a PVC to PVC (compression fitting with top-screw). You have a chrome pipe there, so you need a P-trap that is threaded with the screw below.

Something he didn't mention is that, with chrome, you have to have a rubber washer. If I were you, however, I'd go ahead and replace the chrome wall tube as well (you have a reducing cap behind it). Then you can buy a PVC kit that contains both the trap and the wall tube. This will require a washer for that nut, but once it's done you don't need to worry about it again. The reason to do this is the PVC removes more easily if you have a clog. If that washer on the chrome dries out, you'll have to replace it potentially any time you need to remove the trap.


How long to wait between coats of polyurethane?

We cannot really answer without being there and evaluating the base wood but under 6 hours is cutting it very short. Have I ever done this? yes but it was 4 year dried walnut that was stained ~ 60 days beforehand close to 2 months.
My first 5 layers were cut to thin it down to allow it to fill the small divots and grain, yes this may have been excessive but the next coats were full strength with very fine steel wool at first and later 1200 grit wet dry paper. It still looks awesome 20 years later, but if not allow to fully dry it may bubble or craze. The problems may not show up until the next year on a hot day, I have had that happen, had to strip almost down to bare wood and start applying fresh coats to make it look right. I still have those tables and other than a slight yellowing they are fine after 30 years (not in direct sun).


How do I lubricate plastic rollers for sliding closet doors?

Any dry silicon spray lube will be fine also.  Do not use and petroleum based lubes or WD40. Wet type lubes attract dirt and dust and get very messy. Same advise goes for door hinges.


How do I stop water from seeping between my porch roof and house siding?

I'm going to bet you need kick-out (rain diverter) flashing to divert the water off the roof and into the gutter at the point where the roof/wall intersection ends. It is probably the most left-out piece of flashing and causes lots of problems.

 -kick-out flashing

However, there is no way to tell where the leak is coming from without a thorough inspection of the area. First step would be to check the roof/wall intersection above for proper flashing.


That's most likely iron rust deposit, easiest thing is to ignore it; you aren't going to be drinking from the bowl anyway.

Otherwise turn off the feeding valve flush again to drain and start scraping.


AWG is the name of the wire size, e.g. you want to use 6 AWG wire.

SOOW is a cable type, however it is cordage and not allowed for building wiring.

You want NM-B or possibly UF-B.

It needs to be protected from physical damage, i.e. getting beaned by people moving furniture or carrying in a ladder or whatever.  If you must mount it on the face of the beam,  your best bet is to install it in EMT conduit, which provides physical protection.  However, at that point, you are better off running the EMT all the way from panel to panel, and then, using THHN individual wires in the pipe.  A neat side effect of this is you can run an extra 10 amps, so 70A.

If you lived in Wyoming and drove 85 mph every day, would you want 85 mph rated tires on your car?  Of course not, you don't want to be at safety redline all the time.   So do not get a "60A" panel.  Get more like a 125-200A panel that has plenty of spaces. Like huge numbers of spaces.  Like 30 spaces.

Get a Siemens main-lug panel. This will allow you to use this here transfer switch actually made by Siemens and is Tier 1 quality gear.  ($25 + two $10 breakers).

"But I don't need 30 spaces" -- oh, you just watch!

You will need 4 spaces for the above interlock
A kitchen requires about 8 circuits to be Code, so 8
Dedicated line for 2nd freezer (+1)
Sump pump (1)
Furnace MUST be on a dedicated circuit (1)
eventually you will want to put a lot more circuits so you have the option of having them on generator (10)

So wow, we're at 25 spaces just like that.


Are there any concerns with building recessed cabinets into a house/garage partition wall?

With no plumbing or electrical this would be an easy way to make cubbies. I have done similar at an entry way for shoos and backpacks so they were not scattered around, mine went into the back of a deep linen closet so we did not even notice it.
I did add a fish eye light in the ceiling pointing to them to brighten them up the person that purchased the house had 4 kids and loved the cubbies idea.


How can I make a bluish "white" LED less blue?

Chromatic aberration interfering with reading would be a very unusual complaint (so says an ophthalmologist I know).  On the other hand, cataracts do block and scatter blue light more than the lower end of the visible spectrum.  So, if one has cataracts then it can be harder to read under blue light.  Most "white" LEDs use a monochromatic blue source (not UV), which is then fluoresced to the lower frequencies with phosphor.  Good phosphor is expensive, and more fluorescing hurts efficiency. Consequently, cheap LED sources tend to be blue and have a poor CRI.  Practically speaking, an LED with poor spectral characteristics cannot be improved once manufactured.  You need a different lamp.


how can I check to see if a 4" slab of concrete was actually poured?

If you are only interested in thickness of your concrete slab there is a method to measure it. Sometimes when someone doesn't know the strength of some old concrete element which was poured by someone else people hire specialist for this; they use special tool which is cylinder shaped and which drills the concrete and extracts concrete cylinder, which than you can measure. Don’t be afraid that you will damage the slab because it is only inch or two wide. On the other hand if you are wondering what is wrong and how to fix it you need to provide us with more details. People who wrote comments have asked the right questions, especially Ecnerwal.


What is the right adhesive to use with PVC interior paneling and trim?

There is a product

Roberts cove moulding adhesive - I am sure there are other things better and worse.

Something I consider critical for the project is a Cove shozzle, again a roberts product - it fits on a caulking tube of the stuff, well i guess anyone's product in a caulk tube, and spreads it out wide, so you do not get the kind of squish out, or one thick line of the stuff on the moulding.


what is the best low maintenance finish for a hardwood floor

It's hard to beat Polyurethane for durability.  I have had good success with both water based and solvent based versions. Get the stuff made for floors, probably two coats would do you.  You don't want it too smooth or you'll die when it's wet.

That is, unless you have small children, then I would suggest poured concrete ;)


How to keep an occupancy sensor triggered without motion?

Many occupancy sensors allow you to adjust the amount of time that they can't see you before they shut the lights off. I'm not sure what model you have, so I can't instruct you exactly how to adjust, but setting the timeout time to something longer would probably save you the trouble of building something to circumvent it.

For example, a panel on this Leviton switch pops off to reveal some adjustment controls.

PDF instructions

If your office is managed by your company or a building manager, it may be worth asking the maintenance guy.


Using a bathroom fan with a smaller duct - is there a minimum size?

The small duct will not make your fan "useless".  However, the fan will not perform to its published air handling or noise specifications. Further, its lifetime may (or may not) be diminished and its warranty might be voided. Buy from a seller with a liberal return policy, try it, and return if you are not satisfied with the result.
Another consideration: You could replace the duct with the appropriate size for its entire length EXCEPT for the point where it penetrates the masonry. Although not ideal, this will be much better than with the undersized duct because of the duct's length.  Finally, performance will be even better if the duct is replaced with one that is oversized. This is probably good practice anyway due to its fairly extreme length and this will partially compensate for the flow restriction at the masonry penetration.


Adding outlet to existing outlet controlled by switch

Connection
Plug 1 currently has 3 wires:

White neutral back to the panel
White neutral to Plug 2
Black switched hot to the switch

Run a cable (black/white) from Plug 1 to New Plug.
Add a white pigtail (short wire) and connect one end to both existing neutral wires and to the white wire going to New Plug. Connect the other end to one of the existing neutral screws (doesn't matter which one, except see GFCI issue below) on Plug 1.
Add a black pigtail and connect one end to the existing switched hot and to the black wire going to New Plug. Connect the other end to the existing hot screw on Plug 1.
New Plug gets black on the hot screw and white on the neutral screw. The usual color-coding on receptacles is Black/Hot to Brass and White/Neutral to Silver.
GFCI
All new outdoor receptacles require GFCI. If you already have GFCI "upstream" (either as part of the circuit breaker or at an inside receptacle that is prior to the first outdoor receptacle) then you don't have to do anything special.
If you do not already have GFCI then you need to add it. The catch is that with your existing wiring scheme, you need to add it either at the source (somewhere inside) or at both Plug 1 and Plug 2. New Plug gets protected by Plug 1, provided it is wired correctly, which can get complicated so ask a new question if needed.
Note also that GFCI/receptacle combinations placed outside are likely to not last as long as GFCI/receptacle combinations (or GFCI/circuit breaker) placed inside, due to weather.
Speaking of weather, all outside receptacles should be weather resistant and also include an in-use cover.


Blocking above wall in the way of new ceiling

I am assuming that this blocking is help stabalize the framed wall on the basement walls.  Normally the blocking would be inside the joists so that the 2x4 is even with the bottom of the joists.  Your wall was not put up this way.

Therefore your new ceiling is that low.  You could cut out the 2x4 blocking, install like I said and add another 2x4 under all the way to the drywall and this would stabilize the wall - if done a few times per span.

However you have not much to attach drywall too.  So you would also have to add vertical blocking every couple feed and add more drywall to make this right.  If all of your walls are like this... sorry.  This is a full days work considering the drywall and extra mud and tape.  And even doing this isn't the "right" way.  Your walls should be touching the top of the ceiling for lots of reasons.


Wiring IKEA light fixture into old fixture

What not to do

We get people who find 4-12 non-ground wires they don't understand, and so they take them all apart.  I call this "trying to learn electrical by disassembling your house".   Every wire is now separated and splayed all over the box, and they ask "how does this hook up?"  And we tell them

Wire it exactly the way you found it

And you can (unlike some people).

We don't need to worry about ground, so for purposes of getting the wiring right, we can totally ignore ground.  Grounds are always and only bare, green, or yellow with green stripe.  So ignore those; we'll come back to them later.

It's obvious which wire from the ceiling is neutral.  Neutrals are supposed to be color-coded white or gray, and there's only one wire that could even possibly be.  So neutral is identified; hook lamp neutral to it.  Done.

What remains?  Hot.  Hots are usually every other color not mentioned.  We find 1 wire from the lamp which is obviously hot, and two wires from the ceiling that, they seem like hots and nothing contradicts that.  What is up with that- we really don't care, the point is, that is how we found it, so we hook it up that way unless it's an obvious code violation (and it's not).

So your new lamp hot goes to those 2 black/red wires. I really don't care why.

Now, let's revisit grounds.  Hook all the grounds together.  In fact, it's best to do this first and push the grounds into the back of the box; however I just did this sequence because it's easier to describe.

So what is up with those two hot wires?

Until the lamp is installed and working, I don't care because the first rule is wire it the way you found it.  Now that it's wired, working and tested, we can think about that.  Often, black+red is used to provide separate control either for a light and fan, or for separate groups of lights (e.g. hi/lo, or groups in a chandelier). Typically you find two switches on the wall in this type of installation.

If you have 2 switches and the light is on unless both are off, that's what's going on here. In that case, you should revisit this installation and remove one of the wires from the wire-nut and cap it off (it will be hot so it must be insulated). Don't cut short or otherwise destroy the wire, because the next person might want that feature. If the switch which now controls the light isn't the one you want it to be, exchange hot wires at the light.

I do not recommend attempting to do both things in one action.  Hook up the new lamp exactly as-was, then test and confirm it's working as expected, then modify the circuit.


If I split a 240v 30amp (has neutral) circuit into two 20amp 120v circuits, would that count as two 20-amp branch circuits to meet code?

Yes, if you do it right. This is an MWBC, Multi Wire Branch Circuit.
The keys are:

240V double-breaker (or technically handle-tie is OK, but double-breaker is easier and you better already have that for a dryer anyway).
Feed must include hot/hot/neutral/ground. This might get tricky. A proper modern 30A dryer connection will have all 4 wires (or 3 + metal conduit for ground). However, older dryer connections only had 3 wires. You need to check this first. Upload a picture of the dryer receptacle and we can figure it out.
Replace the 30A breaker with a 20A breaker.
You need GFCI. That can either be done with a 20A double-breaker with GFCI built in (may or may not be available for your panel) or by using a GFCI receptacle as the first receptacle in each chain of receptacles in the kitchen.
The 30A receptacle goes away. Inside the box, run connect two 12/2 (12 AWG hot/neutral/ground) cables. (This could be done with a single 12/3, but that gets confusing and forces you to use breaker GFCI. Easier to avoid it.) The hot (black) wire from one cable goes to one hot wire from the panel. The hot (black) wire from the other cable goes to the other hot wire from the panel. The neutrals from both cables go to the neutral from the panel. All grounds (as always) together.
Each cable can now feed to as many receptacles (15A and/or 20A) as you want. All are ordinary receptacles except that if you did not install a GFCI breaker then the cable goes to the line side of a GFCI receptacle and all following receptacles go to the load side.


Possible neutral problem - Utility side vs. Load Side?

Both your circuits' hots are red wires... Ok... But I follow them, and several pairs of wires are cable-tied together which suggests 240V or MWBCs, ok..., and they both disappear into the bottom conduit, where--

What, the, actual, heck...???

--  there's like 20 red and black wires going into this fat conduit, And Only One Neutral!

You can't do that!!!  A bajillion circuits can't share a neutral!   Each hot gets its own neutral, except for MWBCs where two hots share 1 neutral.  You can't have a MMMMMMMMWBC!

You also can't put more than 9 wires in a conduit without derating (using thicker wire).

This is either a total nightmare, or needs some serious explaining.   Who did this work?


You can hold up 2' of dirt with wood structures. That's essentially what wood planter boxes are. But will it look good? Probably not...at least, not over time. Wood is flexible, gets wet, gets sun damaged, and the posts supporting it will suffer the same fate. If you don't care about looks, then it's probably OK, but if you want it to look OK over time, I'd suggest you consider retaining wall blocks or the like.

UPDATE:

Coming back to this as I think I answered before I saw the photo. I think you could probably make this work. However, I don't see a whole lot of space between the fence and the side of the house. Do you have a basement? If so, this slope is probably intentional to provide adequate surface run-off to keep your basement dry. Do you live in an area where you can get heavy rains at time? If so, I'd suggest not leveling this part of the yard.


You could get some flexible HVAC duct and install it up there. It's only for one register so it shouldn't affect the cooling or heating.


What you call brown is actually "white".

Likely black/red carries mains power.
White/red is a leg down to the switch. L is Load. E is Earth.
Your bulb should span from the black (neutral), to white (switched hot).

You can verify this all with an inexpensive non-contact voltage tester.
See also https://diy.stackexchange.com/a/28019/5960


Can I use existing 40 AMP breakers when the item calls for 30 AMP

It may be possible if the new water heater doesn't state the maximum breaker size.
If the manufacturer only states the minimum, since you are not at 150% I would hook a triple 40a to the new triple 30 water heater.
It is not Code compliant to go the other way from 3 30 with #10 to a 40 this is correct.


my new exhaust bathroom fan wiring issue

Green/Yellow is typically the bonding conductors (ground).  The reason there are two of them is because one bonds the fan enclosure, the the other one bonds the electrical enclosure.  Tie them to the ground wire of the cable you used to power the fan.


Trouble drilling into outside facing wall above window to hang curtain rod

Sometimes when drilling above a window, a lintel is encountered, which may be made of concrete, reinforced concrete, or steel. It may be necessary to move the curtain rod higher so that the  center support mounting can be installed above the lintel. If that is not an option due to curtain length, an "L" bracket can be used to extend the mounting of the support higher. Downside: the bracket will be visible whether the curtains are open or closed. Camouflage with paint if not a aesthetically pleasing.


Wiring garage heater to fit a NEMA 14-50 range plug

Your concept makes perfect sense, and electric heaters are cheap.  For instance a 2000W Cadet heater is $50.   Of course that's made for permanent installation, not that that's prevented me from installing one in an afternoon and then uninstalling it the next day. You just have to use correct, legal techniques.  The accessories to install electric heat - breakers and wiring - aren't expensive either.

Paying for the electricity, on the other hand...

Anyway, if you want the heater to be cord-and-plug connectd, just change the receptacle to a NEMA 14-30 or 6-30, and put same plug on the heater, and change the breaker to 30A.  Breakers are $9.  You can also just hardwire the heater, but still change the breaker to 30A.


How do you connect a light switch with no wires available?

You don't have enough wires between switch and lamp to use hardwired controls.

However, you do have "always-hot" and neutral going to each relevant location.

It's time to go with "smart devices".  You need a smart lamp fixture (or a plain lamp with a smart module), and a smart switch capable of remote-controlling said lamp or module without the use of hard wiring.  Such things either communicate wirelessly, or they induce signals onto the power wires.

It's difficult to give a product recommendation, as these things are blossoming onto the market very rapidly, and the options are ever-changing.  (for that reason, SE's format is to focus on durable advice and not to give specific product recommendations as they are quickly outdated.)

I'm quite sure what your 'maintenance guy' did was intentionally misconfigure your wiring so the light misused the safety ground wire as a neutral/return.  That is an illegal and dangerous thing to do, and we won't recommend it here.  Not least, any wiring problem can put 120V on the light switch cover screws and electrocute you!


Affixing a plastic A4 foil to a (textured) wall

My short list would be:

3M Command strips
Blue tack / "poster putty"
Double-sided foam tape


How can I diagnose an intermittent furnace ignition failure?

Ended up having a technician come out in fear of the intermittent failure becoming permanent in this cold winter.

Issue with this old furnace turned out to be that the gas valves were dirty blocking gas flow to some degree. The technician disassembled and cleaned the valves and went on his merry way.

I learned this is a good yearly maintenance for old furnaces like this.


Cutting and defraying metal railing cable

You are using the wrong tool. You need a cable cutters. These cutters are constructed so they "hold" the strands together while they cut through the cable. See picture below.

In a pinch, you can put a small hose clamp around the wire, tighten the heck out of it and then use  tool with a cutoff wheel or your grinder. Think about getting the proper tool though. It will make your job easier since you've got a lot of cutting to do.


Replacing Lighted Ceiling Fan w Fixed Light

You explained it perfectly and yes, you can keep it that way or switch the black wire from the fixture to the red wire and cap the black. You would want the switch that's the easiest to find, in the dark, to control the light.


It's a "desk with two short legs". :-)

I'd guess it might have been custom made or adapted from something normal by having two of its legs shortened with a saw.

Ikea Hacks
Ikea ADILS/HISSMON


Is it OK to make a forced air register out of wood?

They make wood registers for sale so I would say it will be fine to make one yourself and reusing the adjuster is great for recycling.


You'll want to try pulling it out - it would save a lot of headache if you could clean up and re-glue that joint.

There's small odds that you could cut the loose pipe short, then break out the remaining pipe in the fittings, and then clean the fitting up enough for re-use, if you can't just yank it out.

Otherwise you'll need all the fittings in the picture, plus 3 couplings (or unions, but those tend to be rare in PVC.) You 'll also need more pipe, as some will go for scrap with the fittings. A solvent-welded pipe is almost impossible to re-use.

You will also want PVC cement, AND primer AND cleaner. Dry everything well (if you can't, be sure to get special "wet use" cement - but try to dry it well...) Then clean both parts of the connection with the cleaner, and wait a minute; prime both parts with the primer, an wait as per directions (not too fast, but not so slowly it dries); then apply glue, as per directions, to both parts, and insert with a twist (1/4 turn is a typical goal) then hold them tight for a minute or so (they will try to push out somewhat due to the glue making the pipe expand a bit and the fittings being slightly tapered.) To get something like this where you are working in the middle together (without unions), you typically need to do at least one section of pipe on both ends at once, which is  little tricky.

Or you can try to kludge it with rubber couplings (shudder, though it beats nothing for a temporary fix.)

Beware of old PVC cement - if it's not liquid, but has headed more to the "cold honey - taffy - brick" consistency, it's useless, even if you can still manage to spread it. New glue is cheap - buy small cans unless you have a large project in a short time, it does not keep well. It should be at least as runny as warm honey, probably a bit runnier.


How do I replace a section of a 4" cast iron pipe with PVC?

85 years old. The biggest problem is that cast iron is heavy. By removing a section of the piping you might end up inadvertently messing up the mounts for the old pipe. If it is at all possible I would replace it with PVC, otherwise, I would leave it alone.


Does replacing an electrical junction box require the wiring to be brought up to code?

Anything you arent modifing falls under the grandfather act. You will need to rerun or make a splice in a box in the attic (where ever it is being fed from) to extend the wire to the switch and fan to bring it up to code. You shouldnt need a permit to install a fan. If you do, it just a waste of 300 bucks


Installed Harbor Breeze ceiling fan/light with remote unit - wall switch no longer functions

Taking the information you have given us, what you are describing doesn't make sense. The only way you could connect the fan without it operating on the switch is to bypass the switch, if it is a mechanical switch (not a controller from the previous fan). Meaning you have somehow tapped the line side to the switch and disconnected the switch leg returning to the fan.

You need to take a voltage tester and check which wire is the switch leg and which wire is the line side hot to the switch by turning the switch on and off and seeing which one is permanently hot and which one is the switch leg and reconnect them to reinstall a mechanical switch.

If the switch was a controller installed for the previous fan, you need to replace it with a standard mechanical switch.

Happy new year and good luck.


Unclogging bathtub with an external tower drain

I think what happened is, when the snake got to the "T" where the horizontal pipe meets the tower, it went UP.

A metal snake is always bent a little, which makes it tend to go one way or the other when it gets to a junction.  If you remove the tape, turn it over, and reinsert it, it might go DOWN instead when it gets to the "T" - the bend in the tape will make the tip point down instead of up.

But it would be easier to just snake straight down the tower.  You have cleared the pip from the drain to the T, so going straight down the tower should be fine.

Just remember to go nice and easy with the snake!


Are the resin beads inside old water softeners flammable?

I would highly doubt that they are flammable. Water softener beads are made from zeolites, which are aluminosilicates (minerals containing aluminium, silicon, and oxygen). They are much more similar to clay than organic resins, although they may be manufactured with a binder of some sort.  If you're really worried that they are flammable, try burning some of them - I'm guessing it would be similar to trying to burn a brick.


Holes in drywall slightly too wide for screws

Putting screws directly into drywall, particularly the type shown in your photo, will rarely (if ever) work. The drywall is not strong or firm enough to hold screws without hollow-wall anchors of some sort.

You need to tell us more, however; if you want advice as to what sort of anchoring system you need. What is the reason you need to put screws in the wall?


How can I determine what is causing these electrical problems?

The problem with the light in the new fan/light combo is almost certainly an intermittent connection in the fan unit.

Often these units come with two sets of wires (one for light and one for fan) that you join together at the fixture for operation from a single switch. Your first point of investigation will be to lower the fixture and check that the wire(s) attachments are done properly and securely with good quality wire nuts.

There is also the less likely chance that the intermittent light connection could be in the light part of the fixture itself. This will require careful inspection of all the wiring up to the light socket itself. For some models of fixtures this may require some minor disassembly of the fixture.


Will having a joint between concrete beams weaken a structure?

Yes, it is weakened. The allowable shear stress at a cold joint is greatly reduced from monolithically poured concrete. However, concrete is not that great in shear strength anyway, the reinforcing helps greatly in supporting the beam end. Is the rebar and reduced bond strength enough? Only the beam designer can say for sure. I don't like it, the beam end is the very worst place for a cold joint, but I'm not the designer. It may be OK though not ideal, or it may be a huge problem.


Kids locked the door Then tried to open it without the knob...any advice that won’t cost me a door?

Take a screwdriver and put in in the hole on the left. That should give you enough leverage to retract the latch and open the door.

Replacing the doorknob is a pretty simple DIY job. Though you want to avoid the knob that can be pushed closed while locked to avoid a repeat.


electric shock from brass light switches

If you got shocked twice in a row without moving, that doesn't sound like static electricity. But if you mean you touched them both together and got shocked, or you came back later and got shocked again, that could be static electricity. But based on the circumstances (dry winter air, doing laundry) it seems much more likely it was static electricity.

Frankly, unless your hands were dripping wet or you recently changed the wiring, I would be pretty surprised if you got shocked by a light switch. If you want to check, try turning the lights on and off with something nonmetallic, like a wooden spoon. If the lights turn on and off normally, I think it's unlikely there's an electrical issue (though not impossible). The best way to tell whether the switch itself is electrified is with a multimeter (about $20 for a cheap one at a big box store).


Do I need soffit vents when I have 2 gable vents and 5 normal peak vents?

In a nutshell, yes, soffit vents prevent moisture from doing bad things to your home. Greebo is spot on, you want soffit vents for your air intake.

Without a continuous flow of outside air, the attic heat in the winter will melt ice and snow at the top of the roof, which will flow down and refreeze when it reaches the cooler bottom of the roof. This forms an ice dam, backing water up into your shingles and roof, resulting in some potentially expensive damage.

You also want to draw air in from the soffits which are on the underside of the roof and exhaust it at the top, which requires at least the same, if not more soffit vent area than you have ridge/gable vents. This prevents wind blown moisture from being driven up into a ridge vent and into your attic. If there is a positive flow of air out the ridge vent from the soffits, this minimizes the risk of the ridge vent becoming an intake vent.

And finally any moisture that does accumulate in your attic will be quickly vented away by the airflow from the soffit to the ridge vents. This includes any moisture from the outside reaching the dew point and from any moisture from your home that escapes into your attic from any cracks.


OK, now that we see your edit with the pic we know better. That wire is a water bond for the electrical service. It is NOT being used as a ground, it is bonding the metallic water piping system in the house so that in the case of a live wire or component touching a water pipe the circuit breaker will trip. Can you see where it goes? It should go back to the main service panel.
To add, copper piping can only be used for circuit equipment grounding purposes in some very specific and strict instances. I can quote the code sections but suffice to say it is basically irrelevant since it is just as easy to run a proper circuit or ground to a panel box.
Long ago, like the 60's and 70's it was common to ground some circuits to cold water pipes, but this was found to be unsafe in many instances and has not been generally allowed for quite some time. It is not uncommon to see wires still attached to pipes in older homes.
Older 120/240V household electric dryers and cooking appliances were allowed to be "3-wire", using two hots and only a neutral, the equipment ground was allowed to be omitted and the neutral serving also as the ground. This "3-wire" allowance was removed from the code in the 90's.
Here is the applicable code section for dryers and ranges:
From the 2011 NEC

250.140 Frames of Ranges and Clothes Dryers
Frames of electric ranges, wall-mounted ovens, counter-mounted cooking
units, clothes dryers, and outlet or junction boxes that are part of
the circuit for these appliances shall be connected to the equipment
grounding conductor in the manner specified by 250.134 or 250.138.
Exception: For existing branch-circuit installations only where an equipment grounding conductor is not present in the outlet or
junction box, the frames of electric ranges, wall-mounted ovens,
counter-mounted cooking units, clothes dryers, and outlet or junction
boxes that are part of the circuit for these appliances shall be
permitted to be connected to the grounded circuit conductor if all the
following conditions are met.
(1)    The supply circuit is
120/240-volt, single-phase, 3-wire; or 208Y/120-volt derived from a
3-phase, 4-wire, wye-connected system.
(2)    The grounded conductor
is not smaller than 10 AWG copper or 8 AWG aluminum.
(3)    The
grounded conductor is insulated, or the grounded conductor is
uninsulated and part of a Type SE service-entrance cable and the
branch circuit originates at the service equipment.
(4)    Grounding
contacts of receptacles furnished as part of the equipment are bonded
to the equipment.


How to determine whether my electric wall fan heater is 120 or 240 volts?

Easy.

Connect it 120V. Either you'll get normal heat, or it will be very weak tea.

240V resistance heaters supplied half voltage will work fine, but will produce 1/4 the heat.   This can be used strategically, for instance I have a vehicle block heater sized for using 240V/22A but it will work fine on 120V/11A as well.  That's what we'll do.

Get a #14, 3-prong line cord.  That is 120V (common NEMA 5-15). An easy way to make a line cord is get an extension cord and lop the socket off.

Disconnect the supply wires in the heater's junction box and hook the heater's two supply wires to line cord hot and neutral, and ground to the heater chassis.

Plug it into a Kill-a-Watt meter then into the wall.  Use a #12 extension cord if needed.

The Kill-a-Watt will read watts, which should be no more than 1500. 1500 is midsize for a single heater, like the plug-in heater-fans or oil/"radiator" heaters.  A Cadet 6' long baseboard heater is 1500W.  If the Kill-a-Watt's number makes no sense, and seems like it's 1/4 of what it oughta be, then you probably have a 240V heater.

Then run the heater for at least an hour, and see if it's putting out reasonable heat for a heater its size, or if it's really weak.

Finally listen to the fan, and see whether it seems to be running healthy, or is really anemic.  The fan motor may also have a nameplate you can check.


how to fix damaged wall after peeling off hook?

Many of us have been there. Just get yourself a small tub of spackle or joint compound and dab it on with a brush or sponge. Let it dry and then rub it down with a damp cloth if it's too lumpy or spiky. Apply a second time if it's not filled and textured to your liking.

Once that's done you can prime and paint.


It turned out to be that there was no wax seal on the toilet. I hired a plumber who noticed that the toilet was wobbly and believed that a bad seal was the problem. It’s been a few weeks since he installed a new seal and we have not noticed the sewer gas smell once, so I think that was it!

There were other clues. The previous owner had caulked the hell out of the bottom of the toilet. The floor has a slight slant to it. After pulling up the toilet, the plumber noted that they’d sort of tried to level it with some sort of cement like substance. He tightened the toilet down well, but since the floor has a bit of a slant there, it may loosen over time and that wobbling would degrade the wax seal and it will eventually all flush away. He expects it will need resealed every year or two. (We plan on redoing the bathroom, including pulling up the floor and sistering the joists so we can put down tile, so that should more permanently solve the problem.)

The plumber also noted that with the oversized tub catch, he didn’t think it would siphon even if there was not a vent.

He explained that we smelled it in the kitchen (below the bathroom) because the sewer gas could freely go under the floor and down the wall and get into the living space below. (It’s an old house and thus pretty leaky and poorly insulated.)

He believed that the smell in the dishwasher was a separate issue. He said it was due to backwash from the disposal under the sink. He pointed out some discoloration in the tube that runs waste water from the dishwasher into the disposal. There wasn’t much, but it shows it has happened a bit. He also said that food remnant in the sewer pipes amplify the sewer gas smell. We may notice a smell in the dishwasher from time to time because of this backwash. We haven’t smelled that in quite some time. We don’t use the disposal much because we compost.

There is a vent on the toilet drain, BTW. I overlooked it before.

Side note: I learned what a loop vent is. He pointed it out in the basement. Pretty cool.

Edit: I forgot to mention that that one vent on the roof (which I’d overlooked because it was on the “side roof” [think pyramid] and was gray plastic that blended in with the sky) is the one vent for the entire house. Anything draining anywhere in the house can push the sewer gas (which is heavier than air - as noted in the other answer) up, which is why it was hard to determine a pattern. But also, that opening was there all the time and he said we should have a fairly constant smell. After I mentioned that to my wife, she claimed that she could faintly smell something all the time (which was news to me). I had not suspected a toilet seal breech simply because there was no water damage or noticeable leaks. The plumber explained that you wouldn’t necessarily see leaks when there’s no seal. The waste water only passes through for a few seconds. The plumber was good. He explained everything well. Seemed very astute. It was Povio Plumbing in central Jersey. I recommend them if you live in the area. Oh and he also said that if there was a crack in the drain, you would see this red rust-looking substance on the outside of the drain in the basement because of the type of metal the drain was and there was no evidence of that. And he said that it would definitely be there because the water swirls down the drain and coats all sides.


Equalizing the tanks is not what you want to do. Instead you should allow one tank to be fully consumed before switching over to the second. This gives you the consumption time of the second tank to get a replacement or refill of the first tank. If you equalized and drew down both tanks to empty then you are out of available fuel until you get both tanks filled or replaced. Also if you were in the habit of keeping spare full tanks available on site the first approach only requires one spare tank while the latter requires two spare tanks.

The method used to switch between the two tanks is something you can choose based upon what tradeoff of price versus convenience works best for you. Obviously the simplest is probably a manual switch over valve.


Left switch on gang light pair not getting power

These new smart switches are active devices, and power themselves between supply (their black) and neutral (their white obviously).  Therefore they care about the difference between supply (their black) and switched/lamp power (their red).  Your old switches didn't care about that.

You need the smart-switch black (supply) to go to the bundle of black wires.  The smart-switch red (switched) must go to the lamp/fan, which are the red and black that go into the same cable.

Remember, do not dim a motor.  Motors respond very badly to triac style dimming intended for lights, they need a different type of thing called a fan speed control.


How to seal joints in ductwork when tape is not an option

I've used duct sealer in the past to seal up my attic air handler, it applies like a paste and dries hard. You can try that, but you options of globbing it on may be limited.

Is this duct in a basement or crawlspace?

The handler and ducts in my unfinished basement leak a bit, but I don't bother sealing them up as it helps keep the temp in the basement that much more liveable.


Yes, the sort of thing you are looking for exists; you can find them under the name inlet (opposite of outlet). The most commonly seen type is the C14 socket used on computer power supplies, but ones compatible with regular AC extension cords are also available.

(I'm not able to tell you whether using one in this application would be safe or code-compliant, so this doesn't fully address your question, but I hope knowing what it's called will help.)


Why do unfinished basements need GFCI outlets?

Even "dry" concrete contains considerable water, and is a relatively good conductor. So, it's a relatively good path to ground for a person touching it, increasing the odds of a lethal shock.

Generally, for something to make it into the electrical code, some number of people have probably died due to the lack of it before that happened.


Non-destructive test to determine 110V electrical in backyard pipes?

Use the electric field, imbalanced, into your multimeter. Make a metal pickup, wrap halfway around (so you are likely to have imbalanced Efields, even if +-120 is inside.

Signal strength? Assume 1cm distance between wire and external metal pickup. Assume pickup is 4cm (wrapped halfway around) and 10cm long. Assume air is your dielectric. We'll use the parallel-plate model of capacitance.

C = Eo * Er * Area/Distance

C = 9e-12 * 1(air) * 4cm * 10cm/1cm

C = 9e-12Farad/meter * 40 cm * (1meter/100cm)

C = 9e-12 * 40/100 = 9e-12 * 0.4 ~~ 4pF

We know Q = C * V, and differentiated with constant C, we get I = C * dV/dT

dV/dt = 377 radian/second[60Hz] * 120VACrms * 1.414 ~~~ 60,000 volts/second

I = C * dV/dT = 4e-12 * 60,000 = 240 e-12+3 = 240 e-9 = 0.24 uA.

Across a 10Meg Ohm DVM Rin, that 0.24uA produces 2.4 volts AC.

So, summary use a 4cm by 10cm piece of metal, to which you get a clean metal-contact (copper foil is good, whereas aluminum foil instantly oxides) with one wire of you meter.

Now, you need "ground" of the other meter lead.


How can I replace a Delta 1400 shower valve cartridge?

Ok, I found the problem. Answering it in hopes that it helps someone else someday... The cartridge I bought in the store was in fact the wrong piece. While the white part that is further away from the wall was the correct type the blue part was model UPG 7 vs UPG 2. It looks almost the same but the intake parts are slightly offset.


What are the differences between these types of small-dimension lumber?

There are a whole lot more types of boards than that! Even at the big box stores.

Furring strips come in limited sizes and are not meant to be structural or seen.

Pressure treated boards have a chemical applied to them under pressure that helps presserve the wood against moisture and insects. It's generally used outdoors or in direct contact with concrete otherwise it's not recommended to use pressure treated lumber. The appearance, quality and sizes match other framing lumber used for studs, juists, etc. It would be cheaper to use non-pressure treated lumber.

The better wood to use are appearance grade boards. They'll either indicate they are "appearance" grade or described as S4S (surfaced 4 sides). These will have a smooth surface on all 4 sides. They come in a variety of different sizes and species. The cheapest price is for something the box stores call "whitewood" which is whatever light colored wood they can get the cheapest at that time. Pine, spruce, fir, etc. I think Home Depot might be calling them "common boards" now.

The select grade boards are also appearance grade S4S boards but usually of better quality with fewer knots, hence the higher price. Not necessary for a garage cabinets.

That design you linked to looks like it would be expensive to build. If you want to save money and don't care about appearance you can save money by using a different design that uses 2x4's and 3/4" plywood for the shelves.


AC compressor makes strange constant noise, won't run

Given that you are likely talking about a residential air conditioning compressor with a single phase motor, that sound would be indicative of a failed Starting Capacitor in the compressor motor, so the motor is not able to start. Many of those are hermetically sealed compressors, so the capacitor is separately mounted somewhere away from the motor itself, then there is a "Potential Relay" that takes it off-line once the motor has started (as opposed to a centrifugal switch found on standard single phase motors). So if the capacitor is OK, it might also be a failed potential relay. Either way it's not something the average homeowner can fix, it takes some specialized knowledge of what to look for and how to troubleshoot it. I suggest calling an HVAC service tech.


Diagnostic tools for oven and microwave?

An appliance repairman will have many different diagnostic tools. Unfortunately, diagnostic tools only go so far. Some specifics in your case:

  My microwave (built-in range) that doesn't always heat to the same level.

There are a lot of things that can affect how effectively a microwave oven heats food, beyond any actual problems with the appliance:

Starting temperature of the food
Moisture content
Material (glass vs. ceramic vs. plastic) and shape of dish holding the food
Oven setting (high/medium/low/etc.) - which may seem obvious, but is actually quite different from a conventional oven.

In general, a consumer microwave oven only heats at one level. It varies the time of heating - e.g., medium might heat 2/3 of the time and low 1/3 of the time. While on a conventional electric oven you will typically have 2 (sometimes more) elements, so an intermittent failure of one element might leave the oven working better at some times than at others, I don't know of a similar failure mode for a microwave oven.

If you are heating based on time, the many different variables will result in different results. I would only suspect an actual appliance failure if it sometimes does not heat at all, which could happen if there is an intermittent problem that prevents the magnetron from working.

As far as diagnostic tools, a repairman may have (probably should have) a leak detector. But I don't know of a tool that tests "how well is the microwave oven heating".

  My oven that sometimes pre-heats, sometimes doesn't. Sometimes it starts at 100 and displays incrementally what temperature it is, sometimes it starts at 105-350 (depending on what I set it to) or, if I set it to above 350 it stays at 350 and doesn't tell me when I'm at 400.

Different models (or more generally, different manufacturers/product lines) handle temperature displays, preheating, etc. differently. Some show a temperature (Low->100...350) while preheating, some just show the set temperature (350) and beep or show an icon to indicate the temperature has been reached. There may be variations also based on the particular mode (regular, convection, timed). No real diagnostic tool for the functionality - more a matter of methodically working through the different modes to make sure everything works or to determine what is not working. The one tool would be a good thermometer to verify temperatures. Anything capable of oven-like temperatures will do, but the professional solution is an infrared thermometer like:


Two switch box with 12/2 and 12/3 circuits with cojoined hot wires, is this safe?

Terminology: "crossed wires" is simply a "pigtail" so that the single hot feed can be used by both switches.
This is utterly normal and safe, done normally. Normally is with a wirenut or similar insulated mechanical splice device - I had at first thought that you'd removed a wirenut for the picture - but my second thought is that they are soldered and the joint is uninsulated, which is not normal or safe, but is easily corrected. Likewise, the neutrals and grounds do not appear to have wirenuts, and this makes me think you may need to buy a large container of wireneuts and to check every electrical box you have for wiring done by whoever installed these switches.
So, the hot feed comes in on the black wire of the 12/3 cable, and the switched hots go out on the red wire of the 12/3 cable and the black wire of the 12/2 cable. Where the 12/2 cable goes we don't know, and evidently you don't either as it "does nothing". That part is utterly normal and safe. When you find out where the 12/2 cable goes, you should be able to switch something with it.
The substandard splices are a concern, and the possibility that many places in your home may have similar substandard splices (you had an amateur in this box, we don't know how far they went in your house) is a concern.


Is it a problem if several load bearing studs aren't plumb?

While the world won't end if it stays, the top of the stud should also be moved. It's easy to do and lazy not to. There are a few reasons:

When locating the stud later for mounting photos or whatever a person would be led astray after finding the stud at one height and then trying to hit it at another.
Any electrical or other hardware attached to it will also be (slightly) askew.
Drywall hangers might be frustrated if their sheet ends on that stud or their screws don't hit in the field as expected.
It's technically less strong at a slant, though practically speaking it's not a problem.
It looks shoddy. No contractor I'd hire would leave it leaning simply as a matter of pride.

More concerning are the places where joists rest on unsupported plates (due to the plates being cut completely out). Studs should be added against the duct cutouts to support those areas.


How to determine (not estimate) starting amperage of a motor?

Measuring the startup load is as easy as using a clamp on meter and turning the air handler on and off.

The startup load will be high for a split second, then drop down to a steady load.

Use Ohms Law to calculate the wattage.

Watts/Voltage = Current

As mentioned in my comment, the invertors peak load is a good indication of the invertors motor starting current.

Edit

To get the most accurate motor startup load readings from your meter, you may need to use one that supports "in-rush" readings.

Meters like the Fluke 374, 375 and 376 support "in-rush" readings.

Edit 2

I did some digging around and found the formula to calculate inrush current.

Take the NEMA assigned letter to your motor, in which case yours is letter B, and plug that into this equation:

  Iinrush=(code letter value X horse power x 1000) /( √3 X Voltage)

You can ignore the square root of 3 if  your voltage source is single phase.

  in-rush = 3.54 x 1HP x 1000 / 120V = 29.5 Amps

Bottom line is your invertor needs a surge rating of at least 4000 Watts

  4000 / 120 = 33 Amps

NEMA Motor Letter Table


What is the best way to fill narrow gaps between floor and skirting boards

If skirting board by itself isn't sufficient then you can add a length of quarter round as well.


Understanding why my shower hob is so high

The hob, or curb, lined with that rubber membrane you see there, exists to contain water. Imagine your drain gets a little clogged with hair like shower drains will do, and it starts draining slowly and water stands in your shower. It’s just there to provide a buffer of safety.

The membrane is in place to catch water that gets under the tiles and bring it to the drain, which it will, because grout and mortar are porous materials. Your plumber was probably referring to this.

The second photo, what you were hoping for - that bathroom likely has a rubber membrane under the entire bathroom floor, and the entire bathroom floor is likely pitched towards the drain.


Is it bad/unusual for an oil burner to turn off then immediately back on?

Get it checked.  Sudden stopping and reigniting can cause blowback.  Not real dangerous, but if it stops and loads up with enough fuel and lights, it can blow back smoke and soot.  What you are hearing is not normal, at least talk to your licensed tech about it.


How warm can power cables get while still being Ok?

Most circuit breakers, wire, and equipment are designed to operate up to 75°C which is 167°F.

Normally, they are not that hot, but if they are fully loaded they could become hot enough that you don't want to hold on to them for very long.

Body temperature is pretty cool for a cable operating with a reasonable load on it.

I would not worry until it burns your hand to touch it.


How to unscrew this uncommon type of screw?

Depending on your stair, lighting might be the responsibility of the council. If there's a sticker/notice that has a number for "concerns/ complaints", they'd be the right ones to call. If there's nothing posted, it might be a communal thing. Part of the reason I bring this up is that the replacement bulbs for that lamp seemed really expensive when bought in small quantities. (Or maybe that was just me being a cheapskate. From memory, it was just shy of a tenner.)

But a pair of small-ish needlenose pliers should allow you to unscrew them. If you're naughty, replace with a normal bolt.

If your ceiling is high, be careful on that ladder.


Not really that critical.
While it is generally preferable/best practice to put the pressure switch at/near the pressure tank, it will still work if it's not there.
The pressure at the tank may not match the pressure at the switch, but for the most part, that rarely matters to the extent that it's not the same, in a system with reasonable pipes (size and condition.) If the pressure at the switch is 30/50 and the pressure at the tank is 35/55 or 25/45, you still get water, under pressure.
The default 20PSI differential/hysteresis tends to protect against small effects that would be difficult if the differential was not that large.


How do I repair screw holes in a brick wall?

There are epoxy repair systems for wood. It should work here too. Once it hardens, the epoxy is a tough, sandable, paintable medium that can de drilled. Make sure it keys properly into the hole, so that it does not just pull free under load. This may involve an undercut if necessary.

In fact, I just checked, and there are epoxies available specifically for masonry repair too, but the wood product should be sufficient here, and is easily found in most home stores.

An alternative might be to add a flat wood molding behind the entire length of rod. 3/8 of an inch thick should be sufficient. Paint to match the wall. Now anchor the curtain rod to the wood, using expanding drywall anchors, if necessary.


What's the minimum reasonable thickness for subfloor in my attic?

It depends on the distance between joists or trusses, and the weight of the boxes/items you intend to store there. I personally would not use less than 1/2", and probably at least 5/8".


can I use an unused y2 or w2 aux wire and connect to the C terminal

It looks to me that you can connect either wire to the same terminal as the yellow wire. I would use the brown simply because it is as close to black than any other color. To be honest T'stat control wiring really doesn't have a color code but everyone sticks to the color that the letter indicates for clarity's sake. So disconnect the brown from your control panel and connect it to the C terminal and then connect it to the C terminal in the T'stat.

Good luck


How do I troubleshoot my Kenmore dryer that doesn't heat up?

Some dryers have an in line thermal protection device that can go bad. Trace the wires to the element, or better yet refer to a wiring diagram. You would need an ohm meter to check for continuitiy.


Is it normal to use a grinder to finish a new driveway?

That looks like a very poor finishing job to me. I've assisted on many driveways and never had to go back with a grinder. Finishing it wet is all it takes and leaves the desired surface that isn't slippery. Watch them carefully and hold off on final payment until you're satisfied with the job.


Why does my greatroom have a GFI breaker on the circuit?

Given the locations for these breakers and source of trips, I'm guessing they are actually AFCI breakers. AFCI are designed to detect an arc fault, e.g. a failing extension cord that is at risk of causing a fire. They are required in bedrooms in newer electrical codes. Vacuums frequently trip these because the motor itself gives off a lot of noise in the line that resembles arcing (or perhaps there is some arcing inside the motor).

Since you are seeing it now, look for anything that may have changed, like your holiday lights. Try leaving those lights off for a while to see if the trips stop, and if so, inspect the wiring. Twinkling lights would be another suspect as they turn on and off with a heated element that is likely generating a small arc as it does so.


To supplement what brhans says in his answer ...

Like this but without the middle cable (which is power to the next light & switch, not present in last ceiling rose on a circuit).

You have old colours - black instead of blue, red instead of brown.

Your electrician used the correct two-red cable for the switch, most electrician nowadays use the "normal" cable and put tape around the wrong-coloured wire to indicate it's actual purpose.


AC issues / Insulation of vaulted ceiling

All of your stated options are possible. However, unless this ceiling has absolutely no insulation, or you have a LOT of glass in this room, none of these options will really address the problem.

Put curtains on the windows and glass-paneled doors. Also, rent a FLIR camera, which takes a thermal image of what it's looking at, and take a reading of every surface in the warm room. The thermal picture will tell you if there is a significant rise in temperature anywhere, which indicates improper insulation, or conversely an unexpected DROP in temperature, which in the summer will indicate a leak in the vent. If you do see poorly insulated areas, you may be able to fill in the gaps with blown or spray-foam insulation, or you may have to drop the whole ceiling and reinsulate.

The most likely culprit for poor cooling in one space but not others, other than solar gain through a lot of windows or skylights (in which case curtains and blinds should give you a DRASTIC improvement), is inadequate air circulation into and through the space, or else poor insulation of the ductwork bringing air to this space. The easiest thing to check and fix is the filter; it should be replaced at least once a year and more like once every 6 months especially if you have pets. More than that, and the filter will become so clogged with dust it will impede airflow. The more surface area the filter has, the better, because the more dust it can trap before becoming clogged. I have a 16x25x4" electrostatic media filter and it works just fine for a single system cooling a two-story house. However, the filter will generally degrade the performance of the entire system.

The next easiest thing to diagnose is the condition of the ducts themselves. Take off a vent cover and inspect the inside of the ducts with a mirror; if there's a layer of dust, there's probably more of it closer to the main blower. Call an HVAC crew in for a duct cleaning. Again though, this will likely degrade the performance of the entire system, not just one room (unless there's a leak).

If the ducts themselves are clean, you may need to balance the system. Certain vents will get better airflow than others; it just happens, and which ones get the most airflow depends on the ductwork design. To direct more air downstream, or to underserved areas, partially close the vents in areas of the home that are getting plenty of air, which will direct more airflow to rooms that aren't getting enough. Also consider completely closing the vent closest to your thermostat, thus requiring the thermostat to get its reading from the air coming from other rooms; I've seen plenty of very poor designs where the thermostat is right underneath one of the closest vents to the blower, and so the A/C only runs for 5 minutes at a time because the vent blows cold air right onto the thermostat. This balancing process will require a little patience to get just right. Once set properly, the rooms in your home should each receive the right amount of air to maintain the desired temperature without rooms being too hot or cold.

Similar to balancing the system, understand that doors are very effective "valves" allowing air flow from the vents back to the air returns. If a room is too warm and you want it cooler, opening the door allows more airflow out of the room, which by the same token allows more airflow INTO the room through the A/C vent. Keep as many doors open through your house as possible, especially during the heat of the day. If this is not feasible, you can maintain privacy in your home while increasing airflow by adding a louvered panel to the door, which allows air to blow through.

The hardest thing to fix (impossible sometimes) but still easy to diagnose is the temperature of the air coming out of the ducts feeding the warm room. Get yourself an IR thermometer, and take a reading from each of the vents in the room or house. You should get a reading between 20-30 degrees cooler than the outside temperature. If the air coming out from ALL vents in the house is less than 20 degrees cooler than outside, the compressor is on its last legs, or the coolant is low, or there's condensation in the system. An HVAC tech can disgnose which of these is the problem in a matter of minutes.

If only a few rooms but not others have the problem, the ducts to those rooms are being exposed to outside temperatures, perhaps along an exterior wall or uninsulated ceiling. The fix is to somehow get better insulation to the duct, and you will likely have to tear out ceilings and walls to do this, unless the duct runs through an open attic space. Alternately, you may have a leak along the duct line leading to this vent, allowinfg most of the air to escape, and what's left isn't enough to cool the room. Again, unless the duct's in an accessible attic, you will probably have to tear out walls and ceilings to find and fix the problem.

The reason turning off the ceiling fan helps is that the fan is simply circulating the hot air in the vaulted ceiling above your head down into the room. This requires your A/C to cool the entire space (made more difficult by deficiencies in the ventilation of this room), when you really only need a 6-8ft "blanket" of cool air at the floor. By turning the fan off, you allow the air to "stratify"; cool below, warm above. If you have a nice "blanket" of cool air, and the fan is really high up in the ceiling, you can try extending the downrod of the fan to lower the blades into the cool air, so they grab less of the warm air from above. Keep the fan blades at least 7 feet off the floor though, and I would recommend more like 8-9'. Understand that, fan or not, the warm air will still mix with the cool air at a level determined by how much there is of warm and cold, and if that's at head height, you'll feel little relief even if the air around your feet is 60 degrees.


How can I rewire half switched receptacles?

Yes. The tab between the upper and lower sections of each of these outlets have been broken off on the hot (black) side of the receptacles. There are separate wires running to the upper and lower sections. One is always hot and one is switched.

On the outlet you want always hot on both sections, first determine whether the upper or lower section is the switched section. After the power is turned off, disconnect the black wire on the switched part of the outlet. Cap that wire with a wirenut (and tape for backup). Disconnect the black wire from the always hot side of the receptacle. Make two short pigtails of black wire (about 3-4" each), strip both ends of these wires and attach one end of one of these wires to the upper screw and one end of the other wire to the lower screw on the hot side of the receptacle. Twist the other end of these pigtails together, along with the always hot black wire coming into the box.

This is effectively re-establishing the connection that was removed when the tab between the upper an lower sections was removed to make one half switched.

If there is only one white wire going to the receptacle, you don't need to do anything to that wire.  However, if there is a separate white wire going to the switched half of the outlet, the tab on that side may also be broken, and then you would need to treat it the same as the black.  That is, disconnect the switched white, cap it, create pigtails for the white side and attach them as you did with the black side.

Thanks to DoxyLover for pointing out the possible multiple circuit issue.

Supplement

As pointed out by @Johnny in a comment, an even easier solution is to replace the existing receptacle with a new receptacle that has intact tabs connecting the upper and lower sections (receptacles are very cheap) . Again, you would cap the wires connected to the switched half on the old receptacle, but then you only need to connect the black and white wires from the unswitched side to their respective screws on the new receptacle. The intact tabs will deliver power to both sockets on the receptacle.


Normal expansion and contraction. That's what asphalt does. In Minnesota those cracks show up within two years of road resurfacing due to our weather extremes. It is exacerbated by age, where the asphalt has dried and doesn't stretch as well.


Do I need a sleeve for through the wall air conditioner in new construction?

Ultimately, you'll want to consult the manufacturers installation instructions.  You may find that some units don't have a case, and rely on the sleeve to protect/cover their internal bits and bobs.

Whether or not the unit has a case, installing a sleeve is usually a good idea.  The sleeve allows you to insure the opening is sealed properly, before installing the unit.  It also allows you to remove old units and install new units, without worrying about sealing the opening.


is this a pre-plumbed shower drain? i think/hope it is but not sure


My copper water lines burst, was that actually a good thing for the steel pipes around them?

It is impractical to try to use pipe that is strong enough to resist the stress of freezing water.  You need to insulate it and possible add heat like thermostatic controlled heat cable to prevent freezing . In smaller diameters
Sch 120 steel will probably handle it , but very impractical


GE dimmer works with 3 LED lights, somewhat with 4 and not at all with 5

I think this has todo with minimum load. These dimmers require 50 watt min


Does it mean a broken wire if a doorbell transformer works, but there is little-to-no voltage at the switch?

Switch Wire Continuity
Checking the continuity of the wires between the switch and the chime is easy, finding the break (if there is one) is hard.  To check the continuity...

Turn the breaker that supplies the doorbell transformer off, and verify power is off with a non-contact voltage tester.
Disconnect the wires in the chime that go to one of the switches (don't forget how they were connected, mark them if you have to).
Twist the wires you just disconnected together.
Go to the doorbell button and remove it from the wall.
Using a multimeter in continuity mode (or the lowest resistance setting), touch the leads to the switch terminals.

If the wires are good, you'll hear an audible tone and/or get a reading close to 0. If there is a break in the wire, you'll get a reading of infinity.  If the wires are broken, inspect them along the entire length for damage. If you can't find the break or can't access the wires, replacement might be easier.
Switch Continuity
While you're checking continuity, it may be worth it to check the continuity of the switches themselves.

With the power to the transformer off, disconnect the switch from the circuit.
Measure the continuity in the default OPEN position.
Then press the button to close the switch, and take a reading in the CLOSED position.

When the switch is OPEN, you should get an infinite or very high reading.  when the switch is CLOSED, you should get a low nearly 0 reading.


How to safely and legally join building wire behind drywall

The "best way" is to replace all the damaged wire.
Either completely (from where it starts and ends now) or by adding two junction boxes (which must remain accessible) where you can join the undamaged parts of the wire to new undamaged wire between the two junction boxes. If you can reach one end with new wire, you may only need one new junction box.


Choice of processed lumber for large shelves

Here are some of my experiences:

3/4" boards

The max commonly available width is going to be 12" (11.25" actual), so for 14" you would have to join two 8" boards ripped to width.  This requires more work than the other options and you have to find two very straight boards to start with.  They can warp in the future, but glueing and biscuiting two pieces together helps with that.  It will be strong and light, but I don't think it's worth the effort unless you're really trying to match materials with something else.

Plywood

Will be straighter than boards, but it's not immune to warping.  Comes wide enough to use one piece and is pretty easy to cut.  The cut edge is not acceptable to leave visible.  It may sag in the front over that 60" span.  Even with a back support thats asking a lot (but wait, there is a solution).

MDF

Perfectly straight and will never warp.  Very easy to cut, although it does create a lot of dust.  Same issues as plywood - will sag in front and the cut edge can't be painted easily.  MDF must be painted and will be quickly and irreversibly damaged by water if the surface is not sealed (with paint).

Recommendations

Plywood and MDF are the frontrunners.  If you want to stain, use plywood.  If you are going to paint. MDF is a good choice.  Since neither of them have usable edges, I would glue/biscuit  a 1x2 board onto the front edge.  This gives the shelf a visible thickness, covers the bad edge and adds some strength to prevent sagging.  I still wouldn't trust it to hold heavy items without a center support, but the edge board will at least help it hold its own weight without sagging (and some light items).