Nick Lucchese wrote:
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
Robin Gudgel made the following comment...
The side markings referred to are generic for all of the CBI 13mm wide
breakers. The real distinguishing markings are on the front of the breaker
below the handle. Midnite has a special ETL listing that allows us to mark
the QY series for 150VDC and now the 2 pole for 300VDC. This sticker covers
up the label that says either 125VDC or 120VAC. The markings are on the
front although they use a sine wave marking to depict AC and straight lines
for DC. To make things easier in the future, just use MidNite breakers. That
way if there is no extra label, it must be an AC breaker.
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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