Wrenches,
While we're on the subject of CBI breakers does anyone know a sure
way to distinguish between the AC and DC versions? Depending on the
order we get our stock from both Outback (or Outback vendors) as well
as directly from Midnite. It's obvious with Midnite's 150 VDC MNEPV
stickers but not all of our breakers come from Midnite and not all
who handle them know or are always successful at keeping them
separated. As I look at both options in front of me without Midnite's
sticker it appears quite confusing. Both have identical QA/QZ and QF
markings. I did just notice that the MNEPV does also contain a little
QDC rating on one line, is this the sole indicator or is there
something else to look for when they don't come from Midnite? Even
the AC versions we've been getting still say "+ for DC" embossed on
the side where the MNEPV does not.
Thanks for any insight you're willing to share on my breaker
questions, Nick A Lucchese
On Jul 28, 2009, at 8:17 PM, Exeltech wrote:
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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