The last three white wires were connected to each other with a screw nut. Another white wire was connected to one of the screw-in traveler terminals.
One white wire was connected to the other “common” push-in connector on the back of the switch. The last two black wires were connected to each other with a screw nut. As you can see in the photo a third black wire was fed into one of the two push-in connectors labelled “common” on the back of the switch. However, I’ve uploaded a picture of the disconnected switch for reference as well as a picture of the other, still connected, switch.Īnd I remember the following about the disconnected switch:Ģ black wires were pigtailed and connected to the common terminal screw. Although I’m in the habit of taking pictures before I remove anything, this time for some reason I forgot of course. When I removed the old switch, I found 5 sets of wires (four x 12/2 and one x 12/3) in the box. See his article “Adding an Outside Outlet” in the February/March 2004 issue of Fine Homebuilding (#161).I need to replace a 3-way switch on a circuit that worked fine for years. Popejoy is a licensed electrical contractor in Sacramento, California. Throw on a single- or double-gang plaster ring that comes flush with the drywall, and you’ve got a box that’s hard to overfill.Ĭlifford A. junction box solves most box-fill problems. Although smaller is cheaper, larger may avoid box-fill violations.
Single-gang boxes come in three sizes, 18 cu. What’s the minimum box volume needed?Ģ conductors per 14/2 cable x 2 cables = 4 If a box contains different gauges of wire, use actual volume factors for the wires and the largest volume factor for ground wires, devices, and clamps.Ī PVC box has two 14/2 cables, one 14/3 cable, and one receptacle. Multiply the number of conductor equivalents (total from step one) by their volume factor in cubic inches (listed below)ġ4-ga. Step oneĪdd up the wires and devices, A K A “conductor equivalents” (wires that start and end in the box - pigtails - aren’t counted)
Here’s how to figure the size box that complies with the NEC. If it’s not, you can measure the inside dimensions of the box and figure it yourself. The volume in cubic inches is usually marked inside nonmetallic boxes. Box-fill calculations are done to make sure there’s enough room in an electrical box to accommodate safely the wires, splices, cable clamps (usually none in plastic boxes) and outlets or switches that you intend to put in the box.