[RE-wrenches] Sqd H series disconnects

[Glenn Burt]

We have been using the Siemens line of disconnects. They are designed for
use on DC circuits, and are UL listed for this application.

http://www.sea.siemens.com/us/internet-dms/btlv/CircuitProtection/HeavyDutyS
afetySwitches/docs_HeavyDutySafetySwitches/PV%20datasheet%20Sept2010.pdf

 

-Glenn

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Kirk
Herander
Sent: Monday, March 19, 2012 4:41 PM
To: RE-wrenches
Subject: [RE-wrenches] Sqd H series disconnects

 

Hello,

 

I am combining -4- series strings at the array in a series-fused combiner.
The sum Isc of the four strings is 22.64 adc. I want to use either a
HU361(30 amp) or HU362(60 amp) as a disco at the inverter instead of running
individual strings a long distance from the arrays to the factory-supplied
SMA fused disco. So the Isc rating for the HU361 Is 11.5 amps per pole, the
HU362 is 38 amps per pole. Although not clear in the SQD datasheet, I think
that if two poles are series together the DC(non-pv dc) rating is a full 30
amps for the HU361, and 60 amps for the 362. But the limiting factor in a PV
application is the per-pole Isc rating, regardless of putting 2 poles in
series (this does not increase the Isc rating of the respective disconnect),
correct? I'm assuming my only choice in this instance is to use the 60 amp
disco?

 

Kirk Herander

VT Solar, LLC

dba Vermont Solar Engineering

NABCEPTM Certified installer Charter Member

NYSERDA-eligible Installer

VT RE Incentive Program Partner

802.863.1202

 

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