QO Breakers and Panels [RE-wrenches]

[Allan Sindelar, Positive Energy, Inc.]

Travis,
Square D QO are rated for 50V DC, which means always OK at 12V, never OK at
48, and gray area at 24. Wiles says no, at least in PV source circuits after
NEC, temperature, VOC derating; but we haven't had a problem locally.
Source circuits are current-limited anyway. On load circuits (technically,
on any non-current-limited source, meaning battery) the circuit breakers
need AIC (dead short current) protection, which can easily be provided by a
Class R fuse and holder, mounted inside a disconnect enclosure. It need not
be user-accessible, as it will only blow in a fault mode.
Heinemann CD (fits KOs like the Trace disconnect) and CF (same thing but
panel mount, like Pulse Powercenters) are used in 48V systems, as they DC
rated to 125V. They are available in sizes to 110A. The best wholesale
source is John Mottl at Rainshadow Solar, 360 376-5336.
Homeline has no DC rating.
Allan @ Positive E

----- Original Message -----
From: "Travis Creswell, Ozark Solar" <ozsolar at ipa.net>
To: "RE-wrenches" <RE-wrenches at topica.com>
Sent: Tuesday, March 06, 2001 8:33 AM
Subject: QO Breakers and Panels [RE-wrenches]


> Are Square D QO 's rated for 48 volt (battery) systems?

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