[RE-wrenches] AC Combiner with main breaker as system disconnect

[Glenn Burt]

Beware of breakers used as service disconnects. Most in the range suitable for a supply side connections for PV are really branch circuit rated with 10k AIC which is generally too low for the utility fault current they may be exposed to.
If you can get a statement from the utility with available fault current at the install site you might sneak one in. If you don't want to go to this trouble, use the rating of the exiting main breaker as a minimum value. Usually 20-25k AIC.

-----Original Message-----
From: "Brian Teitelbaum" <bteitelbaum at aeesolar.com>
Sent: ‎3/‎12/‎2014 17:32
To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Subject: Re: [RE-wrenches] AC Combiner with main breaker as system disconnect

One big omission, in the otherwise fine Soligent white paper, is that the 60A minimum disconnect has to be rated as "Service Equipment". Generally this means a "Heavy-Duty" safety switch or Service-rated load center with Main breaker.

I don't see why an AC breaker panel, with a Main breaker, couldn't act as the PV system disconnect, as long as it's Service-rated, a minimum of 60A, and the utility does not require an external-handle disconnect, lockable in the off position. Many utility companies still do.

Brian Teitelbaum
AEE Solar



From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jason Szumlanski
Sent: Wednesday, March 12, 2014 2:14 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] AC Combiner with main breaker as system disconnect

Don't utter the word tap. :)

See:
http://www.soligent.net/documents/HappyLandings_v3.pdf

We usually specify a fusible disconnect for overcurrent protection when grouping the PV AC combiner with the main premises disconnect is not practical.


Jason Szumlanski
Fafco Solar




On Wed, Mar 12, 2014 at 1:31 PM, <kevin at renovusenergy.com<mailto:kevin at renovusenergy.com>> wrote:
I am trying to determine whether an AC combiner panel (for multiple inverter outputs) with main breaker can be also used as the PV system disconnect?

This is for a line tap situation.  I am accustomed to doing these systems with an AC combiner, and separate enclosure for a breaker style, line tap over current protection.

Any thoughts/comments would be appreciated.

Thanks,

Kevin

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