1

I have a Federal Pacific breaker box. I saw some posts indicating that such panels are of low quality. It sounds like I should replace everything; I will try to get going on that.

What would make one of the hot legs on the main breaker burn and get brittle? This is coming from meter glass to the panel. The other side of breaker that feeds the house looks good, no obvious damage.

Why didn't the breaker blow? Does it only protect the house side? The house is the only house being fed off the transformer. Could it have been lightning or a power surge from power lines?

  • 1
    Hello, and welcome to Stack Exchange. We'd like to help, but it's really hard to understand what you're asking. You might want to edit your question to make it clearer. – Daniel Griscom Aug 6 '16 at 1:46
  • Is the burned leg still actively overheating? – ThreePhaseEel Aug 6 '16 at 1:51
  • no it has been replaced, now checking each breaker for voltage, then discounting breaker and checking for resistance with ohm, trying to find problem? – user58384 Aug 6 '16 at 2:03
2

What happened to burn the leg was some combination of two things:

  1. You were pulling excessive amperage through the leg without the breaker tripping to protect the circuit from the overload, resulting in overheating of the overloaded leg.
  2. The leg was connected to the breaker lug poorly/incompletely, causing a high resistance which overheated under normal loads.

For the first, I'd use a clampmeter to diagnose the overload situation. For the second, I'd check for a sagging voltage on that leg (as testing resistance from lug to wire would require the utility to pull the meter).

  • i have unplugged everything from receptacles and i'm reading 110 on everything including the two legs coming in, found some lose stuff when checking resistance fixed that, plugged in freezer got lots of resistance left it unplugged, plugged in another freezer on a different circuit and it is showing resistance left it unplugged same thing with refrigerator and left it unplugged, maybe they where on same leg just not same receiptical? but why all of them at same time or did a surge from outside make them all go bad? what else can be checked? i'm not done with checking every thing yet, – user58384 Aug 6 '16 at 2:49
  • @user58384 Check the voltage on that leg with the system under full normal load... – ThreePhaseEel Aug 6 '16 at 2:53
  • It sounds like the lugs were loose this will cause overheating and insulation to burn off, including the wire/lug to be burned away. I do not like FPE "stab lock" panels and replace them as a priority. But if the wires are loose in the lugs this could be the problem. Just an after thought is this aluminum wire? – Ed Beal Aug 6 '16 at 10:48
  • yes it is aluminum wire, it ended up being common wire being wet and white powder, changed out common from meter to box every thing reading correctly, service box is scheduled to be replaced in two weeks to be on safe side thank for all your help – user58384 Aug 7 '16 at 14:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.