[RE-wrenches] CBI circuit breakers

[boB Gudgel]

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.

Hi Kent,

Could there be a defective module and the breaker is just doing what it 
is supposed to do ??  What is the series fuse rating for those
modules ?  (probably 15A?)   A shorted or defective module would cause 
those other strings to make it trip, if there are enough
parallel strings.   I hope there isn't some kind of intermittent problem...

Was the breaker actually in the "tripped" position or the "off" 
position, since there is a difference?  (tripped of course means
that there is some play in the lever.)

We (and OB) have sold literally over a million (or millions?) of these 
breakers and we just haven't seen any problems.  You have been
using these breakers for years now...   Have you seen problems before 
this ??   I understand that any problems with CBI breakers
have been AC breakers, not DC, and even then, problems have been far and 
few between.

You could test the breakers though...   Just shove, say, 10 Amps through 
one of the questionable breakers and see if it trips after a while.

It seems kind of odd that more than one of these breakers would have 
defectively tripped near the same time ( week ?  day?  week-day?).

There is, I suppose, the possibility that they could all of a sudden 
have started having some kind of problem, but CBI breakers have
had an excellent track record for many years  now.  We haven't heard 
anything from any other customers here at MidNite.

Can't wait to hear what's causing this problem though...  I'm sure it 
will be very interesting !

boB



>
> 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 <http://www.bluemoutainsolar.com/>
>
>
> Allan Sindelar wrote:
>> I have had no problems to date, Kent. Can you be more specific as to what
>> problems you have had? 
>>
>> Allan Sindelar
>> Allan at positiveenergysolar.com
>> NABCEP Certified Photovoltaic Installer
>> EE98J Journeyman Electrician
>> Positive Energy, Inc.
>> 3201 Calle Marie
>> Santa Fe, New Mexico 87507
>> 505 424-1112
>> www.positiveenergysolar.com
>>
>> -----Original Message-----
>> Is it just me, or have other wrenches had problems with the CBI circuit 
>> breakers used in the Outback or Midnite combiner boxes?
>>
>> Kent Osterberg
>> Blue Mountain Solar, Inc.
>> http://www.bluemountainsolar.com/
>>   
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