electricallighting
This switch has 3 screws, but 4 stab-in holes on the back. Is this a 3 way or a 4 way switch? I'm having quite a bit of trouble re-wiring the new switch (got a 4 way, but wondering if this is some type of 3 way – I stupidly didn't take a photo of the wiring beforehand).
The box has 4 wires being used, plus the ground. The top two stab-ins in the photo are labeled "common" (the top right one cracked when removing the wire). Any idea what kind of switch this is?
1st, the white wires should be completely covered with black tape. Try putting both same colors at the top and at the bottom, if you have verified all these wires are the travelers from 2, 3-way switches.
In this diagram the light is off. Toggling any of the switches will turn it on.
If I understand this situation correctly, both red cables are Positive and carry the current from switches. You may want to check both red cables if they really correspond to these 2 switches. If so, I guess You need to choose which circuit (1st red + N + E or 2nd red + N + E) You want to use, cuz I guess You will be using just 1 switch/dimmer (as Your 'new' light needs only 1 Positive cable).
I would check (for safety meanings) red cables (if both run current while switch/dimmer is on), put 1 red to 'A', 1 negative to 'N', 1 earth to 'E' and ISOLATE remaining red cable (using some isolation tape or else). If everything goes well, 1 switch will turn Your 'new' light up and remaining switch would be obsolete.
I'm not sure about all the fixing (if it needs to be done by qualified worker), but I did something like that several times myself.
Best Answer
Take the switch you bought back and get a 3-way
That switch is a 3-way switch (the term "common" as part of the labeling for the terminals is a dead giveaway). Unfortunately, using a four-way as a three-way will probably confuse the next person to work on it, so it's better to take it back and just get a 3-way instead (it'll also get you some of your hard-earned money back as a return credit).
P.S. when you wire the new switch, use the side-screws not the back-stabs. It'll save you a bunch of trouble in the long run.