Agreed. A bad batch is a possibility. We use breakers by the pallet load,
including CBI. We've not seen an issue such as described here, but that
doesn't exonerate all of their breakers. You may be using entirely different
breakers .. or batches.
I deal with UL on a regular basis, and can speak from experience in that
regard. As a UL Listed device, all UL does is test breakers to ensure they
don't trip at current *above* the amperage and time limit specified in the
Standards.
If you have access to a beefy DC power supply with an adjustable current limit,
and can set it for slightly below the rated trip current for the suspect
breakers, you can perform a basic test on the breakers and find them innocent
.. or guilty.
If not .. contact CBI directly and have them test the breakers. Like any
manufacturer .. I'm sure they'd like to know if there's a problem with one of
their products .. if even a specific batch.
Dan
--- On Tue, 7/28/09, R. Walters <walt...@taosnet.com> wrote:
> From: R. Walters <walt...@taosnet.com>
> Subject: Re: [RE-wrenches] CBI circuit breakers
> To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
> Date: Tuesday, July 28, 2009, 9:39 PM
>
> I also had a faulty 15 A breaker on an array with less
> than 11 amps short circuit current. It tripped
> intermittently maybe 4 or 5 times over a year, so we swapped
> it out. Perhaps they had a bad batch?I was going to
> test it at the shop, but didn't have a chance yet.
>
> R. WaltersSolarray.comNABCEP #04170442
>
>
> On Jul 27, 2009, at 6:04 PM, Kent Osterberg
> wrote:
>
> Allan,
>
> I've had trouble with breakers opening when they
> shouldn't. On an array of two strings of
> Mitsubishi 175s (Isc = 7.9A) I had two 15-A breakers
> open. Last week, I had a low-power call from a
> customer with three strings of Evergreen 190s (Isc = 7.1A);
> one 15-A breaker in the combiner was open. Most of my
> installs are around 3000 ft elevation, so the irradiance is
> possibly a little higher than normal, but not by enough that
> it should be an issue for 15-amp breakers. If this is
> a wide-spread problem, I'd expect others on this list to
> have noticed.
>
> As others have mentioned, it is important to take
> precautions to make sure that stranded wires are well
> tightened in these breakers. I tighten, wiggle,
> re-tighten, and then check again later. On systems
> where I've had breakers open, loose connections
> haven't been the issue.
>
> Kent Osterberg
> Blue Mountain Solar, Inc.
> www.bluemoutainsolar.com
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