How to Attach a Two-Wire Lighting Fixture to a Three-Wire Supply

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Connecting a two-wire light fixture to a three-wire power supply cable is not an ordinary occurrence. Three wire supply cables generally carry red and black hot wires of 110- to 120-volts each with a single white neutral wire. The lighting could be added to the three-wire cable provided that the circuit breaker is no more than 15-amps and the wire size is no greater than 14-gauge. You can do the work with the proper tools, materials and electrical circuit knowledge.

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Step 1

Turn off the circuit breaker at the main panel that supplies power to the three-wire cable intended for the light fixture. Tag or otherwise mark the breaker to alert others of the work being done.

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Step 2

Test the wires to verify that no power exists using a voltage tester. Place one probe of the tester on the white neutral wire and the other probe on the black wire. Also test the red wire with the white neutral.

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Step 3

Cut any exposed copper from the red wire with wire cutters. Place a wire nut over the end of the wire and tighten clockwise by hand. Wrap a few layers of electrical tape clockwise around the wire nut overlapping the tape onto the red insulation.

Step 4

Strip 1/2-inch of insulation from each of the remaining wires using wire stripping pliers.

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Step 5

Connect the black hot wire to the black wire of the light fixture with a wire nut. Tighten clockwise by hand.

Step 6

Connect the white neutral wire to the white wire on the light fixture using a wire nut.

Step 7

Wrap each of the wire nuts with electrical tape. Be sure to overlap the tape from the nuts onto the wire in a clockwise direction.

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Step 8

Place the wiring into the box and secure the fixture.

Step 9

Restore power to the circuit and remove all tags and markings from the panel.

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