I'm renovating a bedroom in our house and went to replace the light switch after doing all the electrical outlets.

The old light switch was a 2 wire, a black and a brownish colour. On the new switch there was 2 screws on one side and 1 on the other and a ground. Then there were 2 holes at the top and at the bottom. So I put the black into the hole at the top then other into the hole on the same side at the bottom. Then tested but it flipped the breaker. When try to eject the wires from the switch, I broke the switch so went and got another.. this time a simple 2 wire one.

I checked online, found that both wires were probably live as it was the only switch for the light. After connecting wires, tested it again and it brew the breaker again!

So I resigned to putting the old switch back in the way it was before I started messing with it. Tested again, and it blew the breaker again! I changed the wires around in case I got it wrong, still same result.

Anyone got any idea what might be going on??

Any help would be much appreciated!

  • In the switches I've seen, the connections should go on left and right; using top and bottom on the same side would not be a switched connection. But that shouldn't blow the breaker, so you've done something else wrong too. Unfortunately, it's very hard to say what without seeing the actual installation. I strongly suggest removing that switch and capping the wires for safety, and bringing someone more knowledgeable in to help you sort it out. Tip for future: Don't remove old switch until you're ready to install new one, so you can make sure the now one is connected in exactly the same way. – keshlam Oct 18 '15 at 6:51

If the switch you are replacing is in an electrical box that is grounded there is a possibility that insulation in one if the hot wires is compromised and shorted to the box. This would create a direct short when the wire becomes energized and cause the breaker to trip.

The other possibility is that this switch controls an electrical outlet in addition to a light. Switched outlets are common in living rooms and some bedrooms. In bedrooms with a switched outlet a ceiling light may have been added after the original installation so that the switch controls both. In your case you may have replaced the switched outlet and wired it incorrectly. The error may not have become obvious until you came to work on and replace the switch.

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