[RE-wrenches] Classic 150 100 amp output breaker tripping

Chris Mason cometenergysystems at gmail.com
Mon Nov 2 03:44:03 PST 2015


Good tip, and also prompts me to remind that a thermal camera will see a
lot of problems the eye cannot. We have a fluke thermal camera and I make
it a practise to survey a customer's electrical room prior to doing a
proposal, as identifying the overloaded components can help to avoid the
blame game later. It's the old story, you installed solar so you are
responsible for everything that went wrong later.
I did a survey recently for a customer as part of a proposal and with the
camera could see that the middle phase on their 800A main breaker was very
hot, although it carried the lowest current relevant to the others. The
main breaker was clearly faulty and would fail soon. Had we a solar
installation in place, it would have been construed as being because we
back fed the breaker.

On Sun, Nov 1, 2015 at 3:46 PM, Daniel Duffield <dduffield at me.com> wrote:

> Some years ago, we had a similiar problem with a 50 amp breaker nuisance
> tripping, we over  analyzed the problem and still could not prevent this
> erratic issue, sometimes it would work fine for weeks - sometimes days
> apart, sometimes on sunny days, sometimes on cloudy days.
>  In the end the answer was simple and so easy it was overlooked more than
> once.
> It was just a matter of the proper torque, with the copper compression
> fitting on a Sq D QO breaker, just a hair breathe too loose, enough heat
> would build over many hours to change the trip curve.
> We measured, swapped breakers, everything you could think off until we
> employed a torque wrench with a screwdriver bit.
> Problem vanished, never to come back.
> Not saying this is answer, but sometimes tightening a compression fitting
> to the correct "feel", by a journeman electrician with 20 years experience,
> is not good enough. If your crew or organization has torque screwdrivers,
> we had no excuse not to use them, and back then we found out the hardway.
>
> Daniel O. Duffield
> NABCEP Certified PV Installer since 2005
> EE 98 & ER01, Albuquerque, New Mexico, IEEE member 1995
> DPW Solar (Integration-Division)
> >
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-- 
Chris Mason
NABCEP Certified Solar PV Installer™
Solar Design Engineer
Generac Generators Industrial technician

www.cometsolar.com <http://www.cometenergysystems.com>
264.235.5670
869.662.5670
Skype: netconcepts
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