1970 vintage house, 12ga copper wires, 20 amp duplex breaker.
Tenant complained that a breaker for a circuit in the garage was tripping frequently sometimes when not much load on circuit. They have a fridge, guitar amp and music synthesizer computer plugged in.
I was all set to replace the breaker when I found the hot wire connected to it had burnt insulation 1/2″ back from the connection. I found that the terminal screw was loose and the copper was blackened where the screw contacted it. Wire on the adjacent terminal showed no damage.
I cut the wire back, beyond the damaged insulation, stripped 3/4″ and screwed it tightly in the breaker terminal. I did not remove the set screw in the breaker to burnish it nor did I try to clean out the inside of the terminal opening.
Everything worked fine at first, but now, one month later, tenant reports the breaker tripping again.
Can frequent over-heat tripping [from arcing at loose terminal] have weakened the breaker or is there something else I should be looking for?
Thanks,
Replies
the more times a breakler is tripped, the weaker it gets.
it could very well be that it has been tripped enough that it is weakened to the point of significantly less capacity and is tripping frequently although it is not being overloaded.
oh, and it might rain.
Thanks, but "it never rains in Southern...California"Your location in your profile sounds like part of a line from Dr. Suess' "Sleep Book". I had to read that to my kids so many times I still can recite passages 15 years later.
BruceT
There might be internal loose connections inside the breaker that generating the heat that damaged the wire insulation.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Thanks,Bill. Looks like a new breaker is in order.
BruceT
Due to the bad connection the breaker is overheating. Replace it.
(The bad connection may have started as just a loose screw terminal, but now the terminal is corroded and possibly even the weld inside has gone bad. Just as likely the weld went bad first, causing the screw terminal to overheat.)
Thanks, Dan.I thought the first time I could avoid trying to find a replacement breaker for a 40 year old panel.At least it's not Zinnsco or PushMatic.BruceT
Consider swapping breakers with a circuit with no load on it.
What is wanted is not the will to believe, but the will to find out, which is the exact opposite. --Bertrand Russell
With the wire being loose you have been basically welding between the wire and the breaker. I wouldn't trust the breaker to hold the wire correctly.
Replace it.