[RE-wrenches] NEC 480 - battery enclosure question

boB at midnitesolar.com boB at midnitesolar.com
Tue Dec 13 18:03:56 PST 2011


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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