PSR, Hydrogen, & 110.26

Discussion about the Power System Rack (PSR)
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bflusche
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PSR, Hydrogen, & 110.26

Post by bflusche » Thu May 26, 2005 1:54 pm

Am I missing something in the PSR design, or am I confused between "batteries", "battery bank", and "battery containers"?

1. Browsing through available literature on PV battery installation, I found an admoniton against mounting potential spark producing equipment inside a battery compartment or above a battery bank. The design of the PSR seems to be just that with the short conduit leading directly from the top of the PSR into the DC load center enclosure. Looks to me like the hydrogen will vent into the DC load center enclosure.

2. NEC 2005 110.26 seems to prohibit enclosures or load centers above the battery, so just having the PSR below the PS/PS2 seems to be an issue.

ericwahl
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Post by ericwahl » Thu May 26, 2005 7:51 pm

There is a grey putty sold for sealing/plugging conduit. I have the GB brand available in hardware stores. That should take care of it.

As for your second point, that will depend on the inspector. We have furred out the PS2 enough to have the front of it even with the front of the batteries below. In fact, Sect. 110.26(A)(3) recognizes other "equipment that is associated with the electrical installation" may be located above or below, and even stick out from the wall up to 6" further. I wouldn't argue the point though in the case of batteries below the panel.

But it is good practice to not have the batteries below service equipment if at all possible, and I would not be surprised if this is an ironclad rule for some inspectors. We won't do it again. The main reason being poor access to the batteries.
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