New Breakers Lower Voltage?

Discussion about the Power System PV Combiner (PSPV)

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New Breakers Lower Voltage?

Post by Ecnerwal » Sun Nov 05, 2006 8:14 pm

I was just perusing the flexware price sheet, and found a whammy at the end of it: the old 150V PSPV breakers appear to be getting replaced with new 125V breakers, looking at all the "this part number replaced by that part number, and all these part numbers discontinued" information.

That would be the opposite of progress. I'm not the least bit fond of fuses, especially fuses which cost more than breakers, but if the new breakers are 125 VDC, they won't pass inspection with my 131-134 VOC panel arrays going into them.

What's happening?
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Post by DavidB » Mon Nov 06, 2006 5:10 am

I'm guessing that it is a mistake.. I believe at one point there was a posting here that said Outback would fax you a piece of paper stating the breakers were rated for up to 150V so your inspector would be happy when someone brought this issue up before.

This was back in 2004:
One other related issue is that the circuit breakers we have been using are rated for 125 vdc. We have started increasing their ratings - we just completed an additional listing on the OBPV series of breakers (the skinny ones we use in the PSPV combiner boxes) which increased their approvals to 150 VDC - now we need to do it on the OBDC-60 and the OB-PVGFP/2 as well.

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Post by Ecnerwal » Mon Nov 06, 2006 6:41 am

Seems optomistic. At the time of the post you quote, the "old" breakers had been upgraded (or tested to meet a higher standard, I think, actually) but the documentation had not. In the intervening time, the documentation had been upgraded to reflect 150 VDC rating. But the Replacement Part number includes 125VDC as part of the part number, which seems more likely to be a change than an error, as the 150VDC had made it into the "old" documentation/literature, so I'd expect it to read 150VDC there if the new part was the same rating as the old part.

"Old Part" "Replaced by"

And further down the page, the PSPV breakers are described as:
OBB-15-125VDC-DIN 15 amp 125VDC single pole DIN
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Post by mvrck » Mon Nov 06, 2006 8:13 am

I was sort of confused how the breaker, when in the PSPV, could be rated for 150Vdc, when the breaker manufacturer rated it at 125Vdc. I guess ETL does the up-rating. Maybe Outback forgot to ask ETL to up-rate the parts again or maybe ETL now ask for some modifications to the PSPV in order to comply with 150Vdc.

I guess if you needed the 150 rating, just show the old fax that DavidB mentioned.

Personally, I don't like getting over 100Vdc since the shock hazard goes up. At this point, I only have 6 lives left and want to save them for my midlife crisis...

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Post by Ecnerwal » Mon Nov 06, 2006 8:33 am

The only way I can keep the PV array Max Open Circuit voltage below 125V would be to drop back to a 24V battery, at which point the inverter/wire/breaker costs all go up significantly, as the currents double.

With a 48V battery, in order to have sufficient voltage to charge in the summer, the array has open circuit voltage (not charging voltage) that is (in my case - -20F) up in the 131-135 volt range in winter. Take off a panel and the battery does not charge in the summer...
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PSPV Rating

Post by Erik » Mon Nov 06, 2006 3:20 pm

The PSPV is rated at 150VDC as a unit. This means that if the breakers are installed in the PSPV, they are approved for 150V usage.

There is a supplemental rating when used in this application.
See this document:

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But what is the breaker rating?

Post by CaminoOffGrid » Sat Dec 09, 2006 8:03 pm

I'm confused- installing an under rated component in a higher rated enclosure does nothing to increase the rating of the component. The linked document specifically refers to "Any listed circuit breaker rated 150Vdc minimum" (Italics mine). If the the breakers are only 125Vdc, then you are in essence derating the panel to 125Vdc! So are the breakers themselves rated for 150Vdc or not?

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Post by Kent Osterberg » Sat Dec 09, 2006 9:22 pm

As Erik said the PSPV is rated for 150-volts dc as a unit. This listing document specifies either
Any listed circuit breaker rated 150Vdc minimum
the CBI QY6-G3 circuit breaker, ETL tested to 150 volts.
Perhaps some confusion would be removed if Outback Power Systems would also post the ETL listing for the breakers.

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Post by CaminoOffGrid » Sat Dec 09, 2006 9:48 pm

I remain confused- (It's a common condition for me...)

The question, as I understand it, is if Outback's "OBB-x-125DC*" series breaker are in fact 125 V DC breakers? I understand that if one were to purchase and install an entirely different vendor's, higher rated, breaker that you could take advantage of the overall rating of the panel. But it still appears that the breaker listed in the Flex brochure is limited to 125Vdc and therefore would dearte the entire installation.

Since this thread contains my first and second post in this forum, I hope that I am not out of line. If it helps, my interest is;
- sincere (I have no ulterior motive, like being a shill for a competitor)
- personal (I am in the process of building a fully offgrid system for my family's full time residence)
- somewhat informed (I have worked extensively with large scale DC systems - try switching 27 KVDC at 8A)


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Post by solarstudent » Sun Dec 10, 2006 10:29 am

Here's the best explanation I've seen about this issue.
It's a quote from Christopher Freitas at Outback responding to the same question in another forum.
Thanks for bringing this up as well - the breakers themselves are listed
for 125VDC by UL - we have an additional ETL listing on them for 150VDC
but only when they are used in the approved OUTBACK enclosure products
and only for PV applications.

We put them in the new pricelist listed as 125VDC as that prevents
confusion about what they are rated for when used in other applications.
We did not want to mislead anyone.

There will be new stickers on the inside of the appropriate FLEXware
products which lists the breakers that can be used at the 150VDC voltage
levels. This should make it less confusing for the inspectors.

OutBack Power Systems, Inc.
cfreitas @
Arlington WA USA
Tel 360 435 6030
I hope it's not bad form to post his recent quote (11/9/06) but it, and the sticker he refers to helps clear up the issue.

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