On 2017/02/03 2:41 PM, Jon Elson wrote:
> Had two circuit breakers do something odd at home. One tripped, and I
> assumed somebody had a space heater and a hair dryer on at the same time or
> something. Then, a breaker for my computer room tripped when I turned on a
> laser printer. No unusual loads that I haven't done a hundred times before.
> I unplugged the laser printer, thinking it might have given up the ghost.
> When I reset the breaker, it was noticeably warm, which seemed odd, as it
> was not feeding a heavy load. The laser printer and everything else was
> just fine.
> It took a couple hours for the breaker to cool. I can't remember for sure
> if the breaker that tripped earlier had also been warm, but it might have.
>
> So, anyway, it seems these breakers developed poor contact after just
> staying turned on for several years, and needed the contacts cycled to wipe
> them clean. I have some other breakers in the shop that are used as
> shutoffs for various machines, and they never do this, I guess because the
> contacts are exercised routinely.
>
> Jon
>
It is not the breaker per se that was overheating here, it was the
breakers contacts to the power bus! I suggest you take that breaker out
(safely!!) and check for signs of overheated junction pins on both the
breaker wipers and the bus tab.
Had this happen to a friend and it could have been nasty if they hadn't
noticed it.
John
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