[RE-wrenches] Ground Mount PV DC Disconnects and 690.13

[Dave Click]

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 <dave at independentpowerllc.com>
To: 'Wrench List' <re-wrenches at 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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