[RE-wrenches] CBI circuit breakers

[Nick Lucchese]

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 <walters at taosnet.com> wrote:
>
>> From: R. Walters <walters at taosnet.com>
>> Subject: Re: [RE-wrenches] CBI circuit breakers
>> To: "RE-wrenches" <re-wrenches at 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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