Basics - Safety, Tools, Multimeter, Fuses
Before starting any electrical project, turn
off the main power source to your home by either tripping
(shutting to the off position) the circuit breaker or
removing the fuse at the main service panel. Next use a
voltage detector (see description below) to make sure there
is no power to the site you are working on.
will need the following tools to do any home repair job:
- Voltage detector: This is a
small pen like instrument that you can hold to any
outlet or light and it will light up if the electricity
is still connected to the source. You can find this at
any hardware store.
- Diagonal wire cutters or wire
strippers: All electrical wire is covered with a
protective vinyl coating (insulation). You will need
these tools to strip the vinyl from the wire so you can
connect the bare wire to the terminal.
- Needle nose pliers: These will help
you to get into tight spotsand bend wire.
- Flathead screwdriver.
- Electrical tape: This is used to
cover any open wires.
- Electrical caps: (also called
wirenuts) Small plastic caps used to connect wires
- Multimeter: (also called multitester
or volt-ohm meter) This instrument measures the amount
of voltage from any appliance or outlet. You do not need
this if you are installing anything; rather this will
tell you how much voltage you are getting to a light
that is dim, a toaster that isn’t working, etc.
Doorbells, security alarms, and thermostats all run on
voltage that is too low for voltage detectors to work.
Only a multimeter will work on such low voltage.
|Using A Multimeter:
- On small appliances, to check if a
circuit is complete, unplug the appliance and turn it
on. Set the meter to its lowest range (usually RX1)
Touch the probes to the appliance plug’s prongs. Twenty
to 100 ohms is adequate. Zero may mean there is a short
in the circuit. A high reading indicates an open
- To check a heating element on your
kitchen stove: Remove the element from the stove. Set
the multimeter at its lowest range. Touch the probe to
both terminals of the element. Twenty to 100 ohms is
good. Anything under that range means you need to
replace the element.
Your home should have a power box where the main source of
electrical power enters the home. If you have a newer home,
this box will be made up of circuit breakers which just need
to be flipped to the off position before doing any repairs.
If your home is older, it may have a fuse box as the power
box. The fuses must be removed to disconnect the power. All
fuses and circuit breakers should be labeled. It is a good
idea to have a rubber mat or piece of wood to stand on under
your power box to prevent shock.
All electrical wires are covered by a coating of insulation
to prevent electrical shocks. Each outlet or light switch
has 3 wires going into the power source. These wires are
color coded. Black is always the hot wire which maintains
the electrical source. White is always a neutral wire and
completes the circuit. Green is the ground wire, which
If you have an older home, you may not have a green
grounding wire. Bare copper may also have been used as a
grounding wire. Some homes may only have one black and one
white wire. In this situation, the WHITE wire may be the hot
wire; if the home was properly wired, it would have been
wrapped in black electrical tape to indicate that it is hot.
If you do have an older wiring system, it is best to call a
professional electrician to check it out.
Changing Electrical Fuses
Older homes with fuse boxes frequently “blow” a fuse because
of inadequate power. To change a fuse, pull out the faulty
fuse. To determine the cause of the failure, inspect the
fuse. If the window is cloudy or discolored, the cause was
probably just a short circuit. If the window is clear and
the metal ribbon inside the fuse is separated or parted, the
cause was a borderline circuit overload.
Aluminum Wiring Caution
Homes built in the 1960’s and early 1970’s were sometimes
wired with aluminum wiring. This can be a fire hazard if it
was improperly installed or upgraded. Examine your cables at
your power box. If the cables entering the service panel are
marked AL, they are aluminum. Call an electrician to inspect
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