Selecting Breakers

Discussion about the Power System PV Combiner (PSPV)

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wd8cdh
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Location: Long Island NY

Selecting Breakers

Post by wd8cdh » Thu Aug 22, 2002 8:05 am

When selecting breakers for the PSPV, should they be 1.25 Isc or 1.56 Isc like with fuses?

Thanks

Christopher

Selecting Breakers

Post by Christopher » Sat Sep 07, 2002 9:09 pm

The OutBack breakers used in the PSPV are rated at 100% continuous duty as they are hydralic-magnetic, not thermal type breakers or fuses.

This allows them to be used at there 100% rating.

Christopher

wd8cdh
Forum Guru
Posts: 131
Joined: Tue Jul 23, 2002 11:01 pm
Location: Long Island NY

Selecting Breakers

Post by wd8cdh » Tue Sep 10, 2002 7:54 am

Hi Christopher,

So that means 1.25% Isc (for edge of clouds and snow reflection)?

Christopher

Selecting Breakers

Post by Christopher » Sat Sep 21, 2002 6:49 am

According to John Wiles, the breaker can be rated at 125% of the modules short circuit rating, but the wiring needs to be sized at least 156% of the modules short circuit current. This typically is not a problem for most installations as the wire size is usually oversized to keep the voltage drop low.

I will look for some references in the NEC to document this.

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