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Main house breaker keeps tripping

13K views 20 replies 5 participants last post by  220/221 
#1 ·
Hi all,

This is a great forum BTW and have been reading for quite awhile now. Hopefully somebody can help me with my problem.

I had tripped a kitchen receptacle by pulling it out of the box and the hot had touched the metal box extender. It was wired properly with a red and black wire into the bottom and top and the jumper between is broken off... BUT what they did was shove the wires into the back quick connector parts of the receptacle and DID NOT screw the screws on the side in.

When I pulled the receptacle out a few mm to adjust the plate... the screws touched the metal box extenders and the entire house breaker blew.

Shouldn't just the double pole 15a trip? When I went to turn on the main breaker. I noticed the double 15a was tripped and when I flipped it back on, the main breaker tripped again. I sure hope it not the wiring within the walls...

Can it be the double 15a breaker that is the problem after the short circuit.

Thanks.
 
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#2 · (Edited)
Be happy that one of them tripped, doing its job rather than burning up your wiring. Strange that the main tripped but there is still a short if turning on the 15a breakers blew the main again.
Question- when you turned on the main, did you leave the 15a off or turn it on too? With main on and 15a off, there should not be power in this box but this should be verified first with a meter or other electrical tester before going in.

I would verify that ALL the power is off in that box then pull the outlet and inspect all of the wiring in it for damage. Something else may have shorted inside you didn't see.
All unused screws should be turned in on an outlet to prevent just this from happening- also some electricians like to wrap a layer of electrical tape around the outlet after wiring especially in metal boxes.

Personally I prefer backwire type that screw down the conductors. Otherwise the regular screws for conductors are fine. Quickwire spring types do not give me a secure feeling of a good connection.
 
#3 ·
Thanks for the quick reply...

Since it's off, I pulled the receptacle out and have inspected all the wiring in the box like you suggested and everything looks clean... no shorts or anything out of the ordinary.

It's a plastic box, but since there is tile, the installer used a metal extension and had it grounded as well. He/she did not turn in the un-used screws, so they were fully extended. I'll be putting some tape around it once I figure this out, but am still scratching my head.

Do you think that the wiring in the wall may messed up as well? What are the chances of the 15a breaker failing? That would be an easy fix as I would just go out and buy a new breaker.
 
#4 · (Edited)
It's a plastic box, --- they could have used a plastic extender too !!!:eek:

Do you think that the wiring in the wall may messed up as well? No, not likely if the breaker tripped immediately. :no:

What are the chances of the 15a breaker failing? Anything is possible but if the 15a breaker was off it is likely working- they just both tripped at once due to a short. When the main is on and the 15a is off there should be no power present (to verify by testing).
If you are showing power when the 15a is off and you know it is the only breaker supplying that outlet box, then the breaker may be faulty. This can be checked at the panel VERY Carefully using a tester.

Question- when you turned on the main, did you leave the 15a off or turn it on too? With main on and 15a off, there should not be power in this box but this should be verified first with a meter or other electrical tester before going in.
 
#5 ·
That is correct, there is NO power once the main breaker is ON and the 15a is OFF... I will double check with a voltmeter. I DID get a beep reading on my pen tester, but when I plugged in a lamp, it did not work...

Once the main breaker tripped, I went and turned it on and noticed that the 15a was tripped as well. Once I turned on the 15a, the main breaker blew once again...

What I was going to do after work was remove the wires from the 15a breaker and try to turn it on without any load on the breaker. I'm thinking, that's to see if it's the breaker itself...

Thanks.
 
#6 ·
What I was going to do after work was remove the wires from the 15a breaker and try to turn it on without any load on the breaker. I'm thinking, that's to see if it's the breaker itself...

Thanks.
The above sounds like a good idea.

Ideally, both breakers should not trip. If somebody wanted to take the time to check the "time/current" curves of the main breaker & the 15 Amp breaker, the problem could be solved by selecting an appropriate "downstream" (15 Amp) breaker. But this is not usually cost effective or necessary in a domestic installation. This is more a job for an engineering person...unless you're lucky enough to find a smart sparky.
 
#7 ·
"Once the main breaker tripped, I went and turned it on and noticed that the 15a was tripped as well. Once I turned on the 15a, the main breaker blew once again..."
So- if this was before you fixed the receptacle in question, nothing had really changed. If it was after you checked the receptacle, made sure no wires were welded together, nothing in the box was shorted, then something possibly is wrong with the breaker.

Certainly an easy test is to remove the load wires from the breaker and test for power both in on and off modes. If you replace it make sure it is the same brand and style.
 
#11 ·
I turned on the 15a after I checked the wiring and the box. It still tripped the main.
I replaced the receptacle (with the HOT tab removed) and it's still tripping. I'm hoping that the breaker is damaged as I do not want to run a new 14/3 from the box to the receptacle...

Any suggestions or opinions are more than welcomed. I thank you all in advance.
 
#8 ·
You have a phase to phase fault, that is why the main is tripping also. Look for fused metal between the two hot side screws on the receptacle.

If you replaced this receptacle did you remember to remove the tab between the two hot side screws?
 
#13 ·
Sorry, I thought you had the short solved.

From the start. Kitchen recep? GFCI? 2 circuits? One cable in the box? Other outlets on these circuits?

If there is a GFCI upstream you might have cooked it.


The breaker is NOT the problem.

Remove the receptical(s) from the box and and disconnect it leaving the wires seperated.

Turn the breaker back on.

If it clears the short, the problem is obviouls in the recep or recep wiring.

If the short is still present you need to take apart the preceeding outlets in the circuit(s).

When you re install a standard outlet, wrap the wires instead of back stabbing them.
 
#14 ·
Thanks 220,

It's a kitchen receptacle. No GFI. 2 circuits split and goes to another kitchen recep (same countertop). I don't think there are other circuits upstream as everything else works ok.

Yes, I wrap my wires as I don't like stabbing them in.

I'll do some more troubleshooting, but I'm running out of options...

I'm also at work, so I can't do this until after.
 
#15 ·
I believe that now might be the time to conduct both continuity & insulation resistance tests on the suspect circuit. Unfortunately, this will require the use correct equipment or an electrician with the correct equipment.
 
#18 ·
I don't think there are other circuits upstream as everything else works ok.

You need to determine this. Test EVERYTHING.

I'll do some more troubleshooting, but I'm running out of options...
If the circuit is as simple as you describe it sould be simple. Remove both outlets from the wiring. Disconnect all conductors.

Problem is MOST likely in one of the two recep boxes. Sometimes when they strip the 3 wire cable they slice the insulation . Look for damage/burn marks.

Is the cable at the panel the same exact type as at the recep box?
I'd lose the metal extensions. They cause more fires than they prevent. Use plastic if necessary.
 
#20 ·
Ok... I've repaired the problem. Here's what I did...

Pulled the wires out of the breaker and flipped them on. Tested that there was 120v. Flipped them off and noticed that there was still ~98-100v. Kinda odd. The other 15a had ~50v going through still in the "off" position. I bought new breakers and tested everything before turning them on. I'm glad it all works.

I was definitely thinking the worse.

Thanks to everyone for their suggestions, opinions and help.
 
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