How to Install Switch Controlled Light Fixtures

Grounding Metal Fixtures

All incandescent and fluorescent fixtures with exposed metal parts must be grounded:

• Metal boxes with the nipple or screws holding the fixture to the box will ground the fixture.

• Boxes at the end of a circuit must have the grounding wire of the cable attached directly to the box’s grounding screw or clip.

• If more than one cable enters the box, you will need to make a grounding jumper (pigtail).


Hanging Fixtures

Hanging fixtures also need a grounding wire from the lightbulb socket to the box. Most new fixtures are pre-wired with a grounding wire.

As with any electrical project, the first and most important step is to disconnect power to the circuit by removing the fuse or switching off the circuit breaker. Use a circuit tester (also called a neon tester) to confirm the circuit is dead.

Step 4: Installing the New Light Switch

A two-way or single-pole switch needs to be installed with the right end up. Look carefully at the toggle; it will have the words "off" and "on" printed on it with the words visible depending on which way the switch is turned. Make sure the words are not upside down after installation.

If it says "no" instead of "on" it is upside down. A "decora" type of 2-way switch (a large plate instead of a smaller toggle) should be labeled as to which way should go up, but if not the trial and error method must be used. If the light does not come with the top of the switch pushed in it is upside down and should be turned over.

1. Attach the Wires to the Switch

The green or bare wire always goes to the green screw on the switch. If a 2-way switch (two wires to it) it doesn't matter which screw the non-ground wires go to. If it is a 3-way switch (three wires to it) the only one that counts is the one to the odd colored screw.

If a 4-way switch each wire needs to go to the same place on the switch it came off of. If you are installing a new 4-way switch instead of replacing one, there should be two cables entering the wall box; each cable has two wires in it that go to the switch, plus the bare ground wire.

2. Ground Wires Need to be Connected Together With a Wire Nut

This includes one additional piece of wire in the wire nut to go to the switch. One cable will go to the switch screws on the top of the switch and the other two wires in the second cable will go to the bottom pair of screws on the switch.

Wires are attached to the switch by either pushing into the small hole on the back of the switch or by loosening the screws, wrapping wire around them in a clockwise direction and re-tightening the screws.

As an electrician, I will not use the small holes on the back because over years of time the springs can lose their tension and create a loose connection. If it is necessary to strip the insulation off of the wires there is a "strip gauge" on the back of the switch showing how much insulation to remove.

A little more than that is necessary if the wires are to be wrapped around the screw instead of being pushed into the back of the switch. No matter which method is used, make sure the wires are firmly attached by giving each one a good tug; better it comes off now rather than later after the installation is complete.

3. Put the Switch Into the Wall Box

Once the wires are attached to the new switch, fold them into the wall box as neatly as possible and push the switch back into the box. If the switch won't go completely into the box there is probably a wire nut behind it or a bunch of folded wires—correct as necessary and install the switch using the two screws that came with it or the old ones that were removed.

A 3 way switch. The "odd" terminal is a dark, discolored screw.

Dan Harmon

Wired and ready for installing the switch.

Dan Harmon

Open the Switch Box and Test for Power

Start the light fixture installation project by turning the power off at the main electrical panel, unscrewing the switch and pull it out the switch. Turn the power back on and use a noncontact voltage tester to locate the hot wire.

Connect the fixture and switch

Photo 6 and Figure A show how to connect the light fixture. Start by mounting the fixture strap to the box. Strip the ends of the wires and connect them to the fixture.

At the switch, cut the cable about 12-in. beyond the box. Strip 8 in. of sheathing from the wires and push the cable through the knockout, leaving 1/4-in. or more sheathing visible inside the box. Trim the black and white wires to the same length as the wires they will connect to. Then strip the ends of the wires. Connect the white neutral wires with a wire connector. Connect the wires as shown in Figure A. Connect the hot wire to the side of the double switch that has the “jumper tab” between the terminals (Photo 7). Complete the project by mounting the light fixture, screwing the switch to the box, and installing the cover plate.

Questions Answers

Question: How can I repair a light outlet in multiple lighting fixture?

Answer: If you are talking about something like a chandelier or other fixture with multiple bulbs, you will have to find replacement parts that will accept the same kind of bulb while also fitting physically into where it goes.

© 2010 Dan Harmon

Things You’ll Need

  • Ladder
  • Sheet rock saw
  • Lineman pliers
  • Assorted screwdrivers
  • Wirenut assortment
  • NM type cable (a.k.a. “Romex”)
  • Snake or Fish tape
  • Switch box(es)
  • Switch(es)
  • Fixture
  • Fasteners
  • Spackle or other patching compound
  • Putty knife / scraper
  • Drill and bits.

Wiring a New Light and Switch Loop from an Outlet

This drawing shows the wiring for adding a new lig

This drawing shows the wiring for adding a new light and switch with the fixture coming first in the circuit. New cable is run from the receptacle to the new fixture location and a switch loop cable is run from there to the new switch location. The switch loop is a 3-wire cable to comply with NEC requirements of a neutral in all new switch boxes.

At the receptacle, the always-hot wire is spliced to the black wire on the light fixture cable, and to a pigtail that connects back to the hot terminal on the wall outlet. At the light fixture box, the black wire is spliced with the black wire running to the switch. At the switch, the black wire is connected to the new switch.

Back at the source, the neutral wire is spliced to the white wire running to the light and to a pigtail connecting back to the receptacle neutral terminal. At the fixture, the white connects to the neutral terminal on the light. The red wire from the switch loop is connected to the hot terminal on the light and at the other end to the new switch. The white wire is capped with a wire nut in the new switch box.

Wiring a New Light from an Existing Switch

This wiring illustrates how to add a new light fix

This wiring illustrates how to add a new light fixture from an existing switch instead of from the light fixture. In this circuit, the neutral and ground wires running to the new light are spliced in the switch box with the wires running to the existing light. The black wire running to the light is taken from the switch and spliced with: a pigtail back to the switch, the black wire running to the new light, and the black wire running to the existing light. The switch will now control both light fixtures in the circuit.

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