[RE-wrenches] Rapid shutdown questions

[Will White]

Our experience in MA with rapid shutdown unfortunately varies with AHJ.  Some are letting us put an Eaton NEMA 4 disconnect on the roof next to the array.  Some are letting us put a disconnect in an accessible attic within 5’ of the penetration.  Some are requiring the Midnight Birdhouse remote switch which is expensive.

Rapid shutdown doesn’t apply to pole or ground mounts.

Hope this helps.

Will

Will White
Operations Manager - New England
RGS Energy


64 Main St. |Montpelier, VT 05602
tel 802.223.7804 | mobile 802.234.3167 | fax 802.223.8980

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From: RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mac Lewis
Sent: Wednesday, August 27, 2014 8:32 AM
To: RE-wrenches
Subject: [RE-wrenches] Rapid shutdown questions

Hello wrenches,

I am still trying to wrap my head around how to comply with rapid shutdown in off-grid and hybrid situations.  I've got a few questions that maybe you can help with.

1.  What is a (currently listed) rapid shutdown system that will accommodate 8 strings?  I know I can do this with Midnite combiners but as I understand these aren't listed yet.
2.  On a remote pole mount, does rapid shutdown apply?  If the intent is to isolate a safe zone around an array for fire fighting, it seems as though a standard pole mounted DC disconnect can cover this concern.
3.  I estimate on a typical hybrid installation, rapid shutdown will cost at least $3000 to implement. This includes remote shunt trip battery breakers, contactors on PV side of charge controller and roof combiners, and running control cable from remote disconnect to all locations.  As of now, this would also require me to modify listed interconnection equipment.  Is this what others are finding?
4.  AC coupling with microinverters may be the easiest way to comply with most of these requirements.  However, this doesn't seem like a great alternative to the standard charge controller installation in an off-grid system.

Thanks in advance for your thoughts


--



Mac Lewis

"Yo solo sé que no sé nada." -Sócrates
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