For about two months now, whenever I turn on my porch light, the circuit breaker trips (usually within 10 seconds). I have lived here 15 years and have added nothing to circuit. On the same circuit are kitchen lights, outlets (one with refrigerator), hall light, basement light. I replaced circuit breaker. New one trips just like old one. I found bulb in porch fixture which had glass separated from base. Thought this was the problem, but put new bulb in, threw switch, light went on, then breaker tripped. I have also tested this by unplugging refrigerator and making sure nothing is turned on on this circuit. Porch light still blows the breaker.

Any ideas? Oh yes, I did have a new roof put on last summer. I think this may have broken the bulb in the porch fixture. Perhaps something else was knocked loose? No wires are close enough to the roof to be shorted by nails.

Thanks.

Steve

 

check the switch, they break, they short, they trip. with the breaker off take the light down, check the wire nut connectors in the box behind the light. when they reroofed they could of shook one of the wirenuts loose this would cause a short when to switch is thrown. make sure the breaker is off as the wires in the box will be hot if it isn't.

 

Thanks for the suggestions. I replaced the switch. It made no difference. Then I rewired the fixture itself. Same result. I have an electrician coming next week, but just wanted to be sure I wasn't missing anything I could fix myself. I'm completely stumped.

Steve

 

Steve.
If the problem started just after the roofing job it may be that the roofers put a nail or staple into your wireing. This can be a dangerous situation that might cause a fire eventually as each time it shorts it would heat the wood around the nail. Be sure you or your electricians checks this possibility.

 

I'm having the same problem in my bathroom. Changed the outlet, turned off everything else on the circuit. Trips for no reason. Please tell me what your electrician says. Thanks.

 

GerBa, take down the light fixture leaving the wires from the box hanging in the air not touching anything. If breaker does not trip replace light fixture. If breaker trips with no light fixture connected then open the switch box and look for a second wire being energized by that switch such as an underground wire to a yard light. If you find one disconnect this wire and see if the breaker trips. If breaker still trips then you have a nail in the switch leg wire hit by the roofers. Just replace the switch leg should fix your problem if this is the case. If the breaker does not trip when you have disconnected all wires on the load side of that swtich other than the switch leg then reinstall your light fixture and see if it works without the second load to the yard light or whatever. This is called process of elimination.

Let us know what you find

Good Luck

Wg

 

I found a staple through the switch wire in the attic. I'm too old and large to crawl around in the attic, but this seemed to be the only place I hadn't looked and since a couple of you suggested this as the remaining possibility, I finally did it. It was in the only two inch space it could have happened where some ancient electrician had let his cable run close to the roof. I saw one leg of a staple where it went in and with the point of it coming out.

Tomorrow I'm going to cancel the electrician and see if the roofer will fix this. If not, I'll do it myself.

Thanks to all for your interest and great help.

Steve

 

This is an amazing chain. The problem was very mysterious, and yet several of the experts here were able to put their experience to the task and find this needle in a haystack. Congratulations all!

 

I am not an electrical expert by ANY means but I was a firefighter for 35 years and have seen just about every type of wire fire ever made.