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August 4, 2019 2:40 PM   Subscribe

Just a quick home wiring question about two-way switches.

We have a double two-way switch in the bathroom, each turning on half of the lights. The switch broke and I just replaced it with another double switch (15 amp.) I wired it exactly as the old one was wired: hot red on left top, white on left bottom, nothing on right top, hot black on right bottom. Ground is via the screw into the metal box (not assuming, this is confirmed.)

Now instead of both switches working as they did before, one switch doesn't do anything and one turns on both sets of lights. This is fine but I want to be sure I didn't do something that's about to burn the place down. I've replaced some of the electrical stuff in this apartment before with no issues but I just wanted to check to be totally sure.
posted by A god with hooves, a god with horns to Home & Garden (6 answers total) 1 user marked this as a favorite
 
Most likely the old three way (that’s what you have) and new three way have different wiring so you switched the hot and the runner. Won’t hurt anything since both switches are made to handle 15A.
posted by BrooksCooper at 3:12 PM on August 4, 2019 [2 favorites]


Assuming by 2-way you mean you had two switches in different locations each of which could turn the light off/on. (This is known as a 3-way switch in electrical speak):

Look at your old switches. One of the screws should be black and the other two brass. The black screw is the common terminal and the wire that used to go to that screw has to go on the black screw on the new switch. The position of the other two wires isn't operationally critical.

It's hard to imagine a way one could mess this up that would create a hazard.

PS: if you are trying to look the operation up online out the six wires only one is "hot" the others are travelers or switch legs.
posted by Mitheral at 3:27 PM on August 4, 2019


Response by poster: To clarify the switch I swapped out is one of these, each switch previously controlling a separate light bulb (that now turn on both at the same time.)
posted by A god with hooves, a god with horns at 3:38 PM on August 4, 2019


OK. On both switches on one side there will be a little tab joining together the pads that the two screws thread into (black I think, been a while since I installed one of those). The wire that went to that side has to be the same new-old and the other two wires go to the other side where the two screws aren't joined together.
posted by Mitheral at 3:46 PM on August 4, 2019 [1 favorite]


On further review of your image it is probably the brass side that is joined together on your new switch; the black screws have too much separation.
posted by Mitheral at 3:51 PM on August 4, 2019


The page you link has instructions linked. There appears to be a jumper (fin) on one side that connects the two poles on one side that can be removed. You would want the single wire connected on that side. If one switch does nothing and the other turns on both, it would appear to be reversed.
posted by Short End Of A Wishbone at 4:33 PM on August 4, 2019 [2 favorites]


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