Previous owners installed two wall sconces - one dimmer. That dimmer control plate broke/cracked (a glyder type) I have an Ariadni toggle that I would prefer. The glider had by looking 3 wires (single pole) 1 green, 1 white, 1 black. after turning off breaker, disconnecting I found that actually 2 of each - for the two sconces. I wrapped the two black together as well as the other two color to themselves then connect to the new switch. went to test and breaker/switch "popped" checked connections etc looked fine. turned breaker back on and lights were on. but dimmer wasn't controlling, light are staying on. Breaker off, reconnect no pop but light stay on, disconnect new switch but back old one, same thing - breaker/switch popped. checked wires again hit breaker and lights are staying on for old switch. when the breaker popped did it kill the dimmer switch? the wiring is short as it is so cant keep stripping back. Options or solutions or advice. I have done switches all over the house this is the only issue so far.

old is the wired dimmernew dimmer is square back

  • How was the original dimmer wired? You should wire it exactly like that.
    – Tester101
    Sep 23, 2014 at 14:48
  • It would help if you included a list of all the wires in the box, and which cable they are from.
    – Tester101
    Sep 23, 2014 at 14:50
  • the original dimmer had a black box on back and 3 wires, 2 black one green, the green ground was attached to the two copper ground wires, one black to the two white, and the other black to the two black, the new dimmer is a 3pole switch only two screws (or the hole option)and a ground so I put both the black under one, the white on the other and bare cooper to the green screw, it was hard to get the wires under the screw and thought about putting one in the hole and one under the wire but have read some where what you reference "wired exactly how it was originally", so did not use that option.
    – Nancy
    Sep 23, 2014 at 15:42
  • The wires from "the wall" are all in white casing together through that switch box, 2 bare copper, 2 white, and two black - I am assuming one of each for each of the wall scones, since the old dimmer controlled both. ***Above I meant a single pole (I think) one switch and a slider dimmer option to the side
    – Nancy
    Sep 23, 2014 at 15:46
  • is it possible that I have shorted out both the new switch and old then that would leave the lights constantly on? how can I avoid doing this again if connecting the wires essentially how they were in the first place with a new switch
    – Nancy
    Sep 23, 2014 at 16:02

2 Answers 2


Every switch sits in-between two hot wires. One is always hot, from the mains, and one is hot when the switch is active, and that one goes to the controlled device(s).

It sounds like you have connected the hot wire (black) from the mains directly to the hot going to the fixtures. The always hot switch should be connected to one black wire on the dimmer and the black from the fixture to the other black on the dimmer. Check the dimmer to see if there is a marking to indicate which is which.

The easiest way to test which black wires are which is to use a non-contact tester. Turn off the breaker. Separate the black wires, put a wire nut on the exposed end of each and turn the power back on. Check each black wire to see if it registers as hot on the tester. The one that is hot is the mains. The one (or more) that are not go to the fixtures.

In general, all white (neutral) wires are connected. This assumes the white wire is not being used as a hot line. If it is, it should be marked with a black marker or a piece of black tape. Similarly all greens and bare wires (ground) are connected.

Some dimmers need a neutral wire and some do not. It sounds like yours does. It should be connected to the other neutrals. Similarly the grounds should all be connected.


I'm going to assume; since power has to come from somewhere, that one cable is power from the panel, and the other is to the first light. Which means you should connect the two white wires together with a twist-on wire connector. Then connect the black wires to the switch terminals, one wire per terminal.

When you connected it as in the first image, you created a manual short-circuit device. Every time you flipped the switch on, you created a short-circuit.

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