I have a main panel (unfortunately without a main breaker) and a sub panel. The sub panel is fed from the main panel via a dual pole breaker. One red and one black connection with some pretty hefty looking wire.
When I turn off the dual pole breaker (dual switch connected), the black wire to the panel is no longer hot, but the red remains hot. I see no reason why this would or should happen, except that the breaker has failed. Can anyone concur that breakers do fail in this way?
Thanks in advance.
Well, anything is possible, but I've never seen a breaker fail that way (and I've seen more than my share of bad breakers). More likely you are using a cheap DVM to determine if there is voltage present or not. They are notorious for returning bad readings when no voltage is present. You need a 120/240 volt circuit tester such as http://www.drillspot.com/products/73...Voltage_Tester or a analog multimeter if you can find one.
Also, your main disconnect is probably at your meter.
It is possible for the contact to have welded shut, but does not happen frequently, be careful when working on the system.
Another possibility is a bad neutral on another circuit, which could feed back through that circuit.
Residential breakers typically have a 10,000 amp interrupt rating. I suspect "welding" of contacts is rare.
Are you measuring 240 between red and black with it off? How are you measuring the red wire?
There is probably something else going on. Needs some detective work.
A double pole breaker breaks both legs so you should not be seeing voltage on either side. I have to wonder how you are testing. If using one of those contactless testers, they are notorious for giving false positive results. Athough I've never seen them give a false negative,
Last line deleted as it is very unsafe
IF the breaker was going bad the contact could have overheated, or arced, and welded the switch together. You also have to consider whether there is any chance that you could have a cross connection somewhere that could be "backfeeding" the power into that part of the system.
This is a condition normally asociated with FP breakers a replacement breaker is the fix.
I just tested my main 3 phase breaker at the pole and it Doesnt work at all. Will not shut off. Stuff gets old and tired.
Thanks to all for the quick responses.
It appears that there is *most likely* nothing wrong with the breaker, but something is back feeding the circuit as suggested by some of you in this thread.
This is also evidenced by the fact that the breaker that powers the sub panel and another breaker both seem to be affecting the same set of outlets in the house OR-ing them together.
I have attached a picture of the main panel and one of the sub panel. In the sub panel, it appears to be the breaker at the top right that is the one that is enabling the back feeding.
Ok, so I know this is going to be a tricky problem to unwind. Does anybody have any suggestions here as to make it easier? Is there any way to do some sort of "binary search" by removing particular plugs from the circuit and finding the back feed?
Also, I am going to be fixing this at whatever lengths are necessary, but how dangerous is this situation? Is it simply a case of breakers not tripping when they should or is there something else?
One other question -
The reason I started all this exploring is that I am installing a new bathroom and want to have it on a dedicated circuit. As the main panel is full, I was going to upgrade this sub panel. There is no ground in this sub panel, which I would like to remedy. Can I run a separate ground back to the main panel to feed the new sub panel? or should I run a new large conductor with 4 wires?
Attachment 12574Attachment 12575
Sure looks like a neutral there. You must mean ground.
Yes, you are right, I have changed it to say ground.
There are some major issues with both panels and in my opinion way over your head. I recommend hiring an electrician
I have not ruled out hiring an electrician to get involved.
I am still in the process of identifying what I believe is incorrect. If I never poked around or asked questions, then I would most likely still be using the electrics in this house, blindly assuming that all is fine.
I would be interested to hear about the other issues if they are obvious. I do not need to hear "hire an electrician" as this is certainly not out of the question and something I am open to if I know more about the issues.
First you say this is a main panel that does not have a main disconnect, a code violation
If there is a main on the outside then the grounded (neutral) is required to be isolated from the equipment grounding conductors, a code violation and a danger to those living there
The remote panel (sub panel) does not have the grounding and grounded separated, a code violation and a danger to those living there
Then as you point out somewhere there is a back feed and another danger to those living there and a code violation
It would be impossible to explain to you how to correct these items through a discussion board such as this one and my very best advice it to hire an electrician before you do something that causes you home to go up in smoke or even worse
Is there any reason why I would not be able to replace the sub panel once I have corrected the back feed? Can I run a separate ground from the main to the panel, or should I run a new 4 conductor wire? Once I have a grounded sub panel, I can then update the wiring that feeds from it, opening walls as necessary.
I see no reason why doing this puts the wiring in a worse situation than when I started - no ground to the panel and a back fed circuit.
I can consider upgrading the main panel after this is performed. I do not expect all the answers from this board, I was just hoping to get some general advice. I also feel that most of what I need to do can be accomplished without an electrician, except for the replacement of the main box/connection to the feed. I have done some reading, will do plenty more and will stop if there are issues I feel I am unable to tackle.
And thanks jwelectric and others for your time and knowledge.