Wiring a Second Basement Light Switch with 14/3 Cable

Crystal's basement had one switch at the top of the stairs, and it turned on only the light at the bottom. Everything else, including the storage area and a gaming section, needed a pull chain, so she was walking into the dark. Master electrician Heath Eastman came to rewire it, and the job ended with two switches controlling separate parts of the basement.

Finding the circuit

Heath's first step was to turn off the power. He took the bulb out of the first fixture and threaded in a circuit breaker tracer. At the panel, he explained, the tracer goes around the breakers once to get used to the panel, then finds the right breaker on the second pass. The light went off, and the rest of the lights were off too.

How the circuit was wired

Inside the fixture box he found power coming in from the panel to this light, then carrying on to the other basement fixtures, which is why they ran on pull chains. A separate cable went up to the switch: power travelled up on the white conductor, and came back down on the black wire to the fixture.

The first fix

The fix was to move the one wire from the wire nut that went to the other lights and attach it to the terminal on the light at the bottom of the stairs. He then tied the two remaining wires together with the wire nut. With the breaker back on, one switch ran all the lights. Crystal found them very bright and suggested splitting the basement in half, storage on one side and gaming and workout on the other.

Adding a second switch

Heath turned the breaker off again and took apart the switch. To light the two areas separately, he replaced the 14/2 cable from the bottom-stairs light to the switch with 14/3. The extra conductor gives constant power at the switch box while still sending switched power down to the storage-area lights. He also added a new 14/2 from the switch box to the back lights that serve the gym.

For the two-gang old work box, he scored the plaster before sawing, to keep it from chipping. He pushed the saw in, pulled it back slightly and then out, so it cut only on the stroke in. The old wire, loose and fished in the wall, was cut at the bottom and used as a pull for the two new cables.

Splicing the new box

Heath did not trust the stamp on the first box, so he switched to one with its ratings visible and enough room for the added wires. He joined the grounds together, then the neutrals. One pair of wires was the feed from the panel, which now goes up to the switches, and a red wire coming down switches the storage-area lights. The old wire running over to the gym was left in place, separated and capped in the back of the box, so the setup could be swapped back later.

With the bulb in and the breaker on, the gym lights and then the storage area came on from their own switches. The fixtures with pull chains that were not replaced no longer need the chains.