Dan,
While the battery box, or maybe the whole room they are in, do fit the
definition of a Class 1 Division 2 location, I don't think it is
consistent with the intent of that section. Wring methods for hazardous
locations are specifically designed to keep the wiring isolated from the
hazard. That notion doesn't work batteries - they are the source of the
hazard and the wires do run to, and into, them. To be complaint with the
requirements for hazardous locations the batteries would have to have
integrated gas tight junction boxes enclosing the terminals. And
interior of the battery would still remain an explosive environment with
energized conductors no matter what is done to wiring on the exterior of
the battery. Batteries are a special hazard and wiring methods specified
for Class 1 Division 2 locations won't mitigate that hazard.
It takes a lot of ventilation to keep the H2 levels below the explosive
threshold.
Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com
t: 541-568-4882
On 12/14/2011 4:46 PM, [email protected] wrote:
I've mentioned it in the past, and got the impression it went over
like a fart in church, but it seems to me buttoning up a battery box
tighter than a bull's ass in fly season, and (hoping) mechanical
ventilation mitigates this creation of a hazardous environment creates
a Class I, Division 2 location. (NEC 500.5 (B)(2)(2)).
Any takers?
db
Dan Brown
Foxfire Energy Corp.
Renewable Energy Systems
(802)-483-2564
www.Foxfire-Energy.com <http://www.Foxfire-Energy.com>
NABCEP #092907-44
-------- Original Message --------
Subject: Re: [RE-wrenches] NEC 480 - battery enclosure question
From: Ray Walters <[email protected] <mailto:[email protected]>>
Date: Wed, December 14, 2011 11:52 am
To: RE-wrenches <[email protected]
<mailto:[email protected]>>
110.11 Deteriorating Agents. Unless identified for use in
the operating environment,no conductors or equipment
shall be located in damp or wet locations; where exposed to
gases, fumes,vapors, liquids, or other agents that have a
deteriorating effect on the conductors or equipment; or
where exposed to excessive temperatures.
Informational Note No. 1: See 300.6 for protection against
corrosion.
110.18 Arcing Parts. Parts of electrical equipment that in
ordinary operation produce arcs, sparks, flames, or molten
metal shall be enclosed or separated and isolated from all
combustible material.
300.6 Has a lot of good info on corrosion that we in the solar biz
should be all over, as well.
So that's 3 pretty specific code references.
Ray Walters
On 12/13/2011 7:03 PM, [email protected] wrote:
On 12/13/2011 5:47 PM, Dan Fink wrote:
Esteemed Wrenches;
An email question from my recent Home Power article on charge
controllers that I'm unsure of.
Does NEC specifically forbid mounting other gear, such as charge
controllers, inside a battery enclosure? How about shunts?
It's not in 480 that I can see, and 480 doesn't seem to treat
the interior of a battery enclosure as particularly explosive,
because as per 480 it has to be adequately vented anyway.
Of course there are a zillion common-sense reasons not to
actually DO that -- even an MX60 has a relay that can spark--
and of course corrosion on the controller terminals, circuit
board, etc. Bad news all around and I never do it. I learned
this as an apprentice back in the 1990s, and I just don't do it.
But I do put shunts in there sometimes...is this a no-no? The
shunt terminals are brass, I've never seen any really nasty
corrosion build up, but I'm quite curious.
BUT I'm wondering if I'm missing something obvious in some
other NEC section etc.
Thanks in advance!
Hi Dan. Nice article, BTW !
The NEC doesn't say that you CAN do this, but it does not
dis-allow it either.
It will come down to what the battery manufacturer says, is what
we have found.
Sealed batteries are the only ones that can be mounted in a
battery box with
arc and spark equipment.
Look at UPS's that you buy from COSTCO for instance. They are UL
listed, usually.
boB
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