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Electrical and Lighting
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How do I connect 3-way switches?
This example assumes power arrives at a ceiling light fixture
with 2 wires, which is a standard arrangement setup. Power then goes from the fixture in the middle
to each wall switch via 3 wires, which are black, white and red. For clarification purposes, your
arriving black and white wires are called common wires and the three wires are travelers. The common
black brings the power.
At the light, connect the common black to the black traveler
that goes to switch A. At Switch A, connect the black traveler to the common terminal (darker in color
or marked common). Run the common neutral wire (white) to the light. At Switch A, connect the red
traveler to a traveler terminal. Connect the white traveler to a traveler terminal on Switch A and
mark the end black with tape or paint to show it's hot.
At the light, connect the red traveler to the red traveler that runs
to Switch B. At Switch B, connect the red traveler to a traveler terminal. At the light, connect the
black traveler to the light. At Switch B, connect the black traveler to the common terminal. At the
light, connect the white traveler from Switch A to the white traveler from Switch B. At Switch B,
connect the white traveler to a traveler terminal and mark it black. That should be it. Do not twist
the wires before putting in the wire nuts; let the nuts twist them tight. Also,
do not use push-in connections; put wires around the screws.
I have an old house with only two wires coming to each outlet and switch, and no ground. Can I ground this system?
Yes, in one of several ways. The
simplest method is to add a ground fault circuit interrupter (GFCI) at the beginning
of each circuit. Find the first receptacle in the circuit (the one first in line from
the breaker or fuse panel) and hook it to the "line" side of the GFCI. Then connect
the wire going to the remaining outlets on that circuit to the "load" side of the
device. Now you can replace all the remaining outlets on that circuit with regular
three-prong grounded outlets. These work well for all outlets except for major
appliances like refrigerators.
If you have metal armored cable
that contains the wires to the box, you can install three-prong receptacles and
ground them in the following manner. First, with the power disconnected, replace the
two-prong outlets with three-prong. Connect a green jumper wire (which you can buy
with a screw already mounted in it at hardware stores) from the green grounding nut
on the new receptacle to the box. Screw the jumper wire into the 10/32 threaded hole
in the box. Make sure the armored cable is firmly attached by a metal clamp inside
the box. If the box has no threaded hole, you will have to drill a hole only slightly
smaller than the screw and drive the screw in tight.
If the wires are not in armored
cable, you cannot ground them according to code. Use the GFCI as detailed above.
I am adding a dishwasher to my older home. Does it need its own circuit
or can I just connect it to the existing wiring above the countertop?
A dishwasher should have its own
circuit, separate from the two individual appliance circuits that should be above
your countertop. Although you may see dishwashers connected to existing wiring in
older homes, the problem really lies in the breaker or fuse. In older homes, the
breaker or fuse may not be as functional as current ones. Thus, if your dishwasher
overloads the circuit, the older breaker or fuse may not pop, and your wiring will
heat up to dangerous levels.
Can I add a phone line to my house by myself?
You can install two separate
phone lines from your existing wiring if you already have relatively modern telephone
wiring. Phone wiring is low voltage, but if the phone rings while you are holding a
wire, you will get a jolt. So go outside to the phone service box, open the
right-hand side, and disconnect line one and line two. Next, remove the cover on the
phone jack in your house and look at the wires. If you have at least four wires
visible, you can add a second line.
On older systems, you should
see a black, yellow, green, and red wire. Line one uses green and red; line two is
black and yellow. The wires in the jack are probably already connected. If not, strip
off a half inch of the plastic coating on the end of the unconnected wires and fasten
them under the two unused screws. (If your phone doesn't work later, just reverse the
two wires.) Purchase a splitter and a phone cord that has at least four wires in
it—red, green, black, and yellow—at your local phone store. Connect the outside
wires again, then plug the splitter into the jack and the two phone cords into the
splitter. Now call the phone company and tell them you are ready for a second line.
If you have newer phone
lines, you will see the following wires: blue and blue stripe (line one), orange and
orange stripe (line two), green and green stripe, and black and black stripe, which
are extra pairs. In this case follow this color code system: blue wire to red
terminal and blue stripe to green terminal for line one. (That should be in place
already.) For line two, connect the orange wire to the yellow terminal and the orange
striped wire to the black terminal.
How can I remove a stuck and broken lightbulb?
First, unplug the lamp from the
receptacle or, if a ceiling fixture, make sure the switch is off. Usually you can
grasp the broken lightbulb base with a pair of needlenose pliers and turn it to remove
it. If the bulb is stuck, push the end of a potato into the socket and turn it out
that way.
I want to install a new light switch. Does it matter which wire goes to
which screw? I thought the hot wire went to the gold screw and the neutral
wire to the silver screw.
You are confusing a receptacle
with a switch. Before working on a receptacle or switch, make sure the power to
that area is completely off. On receptacles—not switches—the black (hot) wire goes
to the gold screw and the white (neutral) wire goes to the silver. There should be
a third (green) screw for the bare copper grounding wire.
Switches that control one light
are called single pole switches. They have only two screws, and it doesn't matter
which wire goes to which screw. (Older wiring may have only two wires, both in black
fabric.)
A three-way switch, however,
is different. (See below for further explanation.)
I want a switch at the top and bottom of the stairs to control one light.
How do I do this?
Three-way switches that control
a light fixture from two different locations are always used in pairs, such as at
each end of a room with two exits or at the top and bottom of stairs. Each switch
is readily identifiable by its three screws and because it has no on/off lettering
on the switch. Two of the screws are either brass or silver colored, and the third
is black or copper colored. Using them requires what is called three-wire cable plus
a ground. You cannot use two-wire with a ground, commonly called by its trade name,
Romex, for this purpose. The wiring is more complex and requires the novice to
follow diagrams.
What's a "switch loop" and how does it work?
In a switch loop, the hot and
neutral wires arrive at the light fixture before reaching the switch. If you simply
connected the wires from the light to the switch, the light would always be on. To
make a switch loop, connect the incoming hot (black) wire to the white neutral wire
that runs to the switch. Mark the white wire at each end with black tape or black
paint to indicate it is hot. Now the incoming white neutral wire is attached to the
light fixture, as usual, and the black wire from the switch is connected to the
light fixture. In this way, the hot wire initially bypasses the fixture, then loops
through the switch and back to the fixture.
Why does my smoke alarm keep beeping?
If the beep is every few minutes,
your battery is probably running low. If it's a photoelectric design, you also
could have a bit of dust and dirt in the unit, which might cause a malfunction.
Clean it and check the battery.
My kitchen range is wired with aluminum wire and is connected directly to
the house's copper electrical wire. Is this safe? What's the problem with
aluminum wire?
The main problem with aluminum
wiring is that it expands and contracts more than copper. If you have a loose
connection, there is greater chance for electrical arcing, heat buildup, and possibly
fire. Aluminum cable is still used quite frequently in sizes 6 and larger. The
thing to look for (with the power off) is that the lugs (terminals) connecting the
aluminum wire to the copper are suitable for copper or aluminum. They should bear
the letters "cu/al." If the lugs are copper only, replace them. The ends of aluminum
wires should be dipped in Penetrox, an antioxidant compound, before being attached to
the copper wire in the cu/al lug.
I want to connect a new ceiling fan, but there are only two wires and a
ground wire coming out of the ceiling. But my fan has a black, white,
and a red wire. What is the red for?
The red wire allows you to turn
on the fan without the lights, or the lights without the fan, assuming you have a
stacked switch with the fan. To make this work right, you would need three wires
(black, white, and red, plus ground) from the ceiling fixture down to the switch.
But since you only have two wires in your ceiling box, the wall switch will turn on
both lights and fan together. You can attach a chain beneath the fan to control the
lights or fan separately, if you wish.
Two of the four outlets in my bedroom won't work. What's up?
Turn the circuit off and inspect
each receptacle. Receptacles are often wired with the push-in method in the backs of
them rather than using screws. Wires connected by the push-in method can become
loose. Remove the wires from the back and attach them to the receptacle screws.
If that doesn't work, try new receptacles.
How can I stop my fluorescent lights from buzzing?
The buzz is caused by the
ballast (transformer) in the lighting fixture. Most residential fixtures use
magnetic ballasts that operate at 60 hertz, which creates audible humming and
flickering. Your solution is to replace the magnetic ballast with electronic ballast,
which operates at 20,000 to 40,000 hertz—essentially continuously. This completely
eliminates humming and flickering.
The electronic ballasts only
work with the new thinner diameter fluorescent tubes, called T-8s.
If you convert your fixture to
electronic ballasts and T-8 lamps, you will notice a huge improvement in quality.
No more humming and flickering—and much better color rendition from the higher
quality T-8s.
My fluorescent bulbs are dim and won't get brighter. Why?
If you are sure that the lamps
are good, then check to see if the two incoming wires, black and white, are making a
good connection. First, turn off the power to that light, and then remove the cover
in the center of the fixture. If the connections are tight and the lights still don't
work properly, you will need to replace the ballast. That's the black rectangular box
with probably six wires coming out of it. Basically, you will just cut the wires off
the old ballast and connect the wires from the new one with wire nuts. Just match the
colors. You can get ballasts and small wire nuts at any home improvement store.
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