I'd agree that 690.13/14 don't require a DC disconnect out there
(notably 690.14(C)(5)). I'd still think it's a good idea for maintenance
and safety so that you don't need to go 300 feet to turn off power and
worry about lockout/tagout.
You would have to wire the two outer poles in series to use the 361RB
disconnect per its UL listing. Per Schneider Electric's "Self-Certified"
method you'd be fine breaking it just once (the 30A disconnect can take
a 12.8A Isc).
-------- Original Message --------
Subject: Re: [RE-wrenches] Ground Mount PV DC Disconnects and 690.13
From: Dave Palumbo <d...@independentpowerllc.com>
To: 'Wrench List' <re-wrenches@lists.re-wrenches.org>
Date: 2010/3/30 10:43
Wrenches,
For a ground mounted PV array I do NOT see where 690.13, 690.14 mandates
a DC disconnect at the array itself. My question is what do you do as
“best practice” for safety, or for service of inverter disconnect. I
have been using 600VDC SQ-D disconnects at our ground mounts and I’m
wondering if it’s just plain overkill, or reasonable practice.
For example: 4kW Ground Mounted PV array with a Maximum Voltage of 567
DC. DC wire run (buried pvc conduit) of 150 feet to the inverter with
integral DC disconnect. Inverter is located on outside wall of the house
next to utility service.
Also. With this system, if I use a DC disco at the array, can I safely
use the SQ-D HU361RB 30 Amp 3 pole 600VDC disconnect. The system is one
string of 20 Evergreen 205’s, so 11.93Isc x 1.25 for a current of 14.94
Amps Max. By using 2 poles in series can we use this disconnect safely?
Dave
David Palumbo, NABCEP Certified PV Installer
Independent Power LLC
Offices in Lamoille and the Champlain Valley
802.888.7194
www.independentpowerllc.com
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