Hi Wrenches;
I have an upcoming project to be inspected, ,and having spent too much
time on off grid and out of country work, I'm now playing catch up with
the new 690.12 and 690.71(H) requirements.
The proposed GTB system is 3 Radians with a ground mounted 18kW array
and large HUP battery bank. I just read a Bill Brooks article that
basically says that Rapid Shutdown not only applies to ground mounted
arrays that come into buildings, but also applies to battery cables if
longer than 5 ft.
There are 690.12 compliant combiners from Midnite that work with their
Birdhouse system, so I think I've got a handle on the array requirements
(more or less).
What is stumping me is how to feed three 8kW inverters from a large
battery, and install auto disconnect breakers within 5 ft.
1) the disconnect has to be large enough, Midnite only makes a 250 amp
remote trip breaker, so I'd have to parallel 3 of these?
2) 690.71(H)3 says the breaker can't be in the battery enclosure, which
is tricky since the enclosure is 160" long from one end to the other
with 2 parallel strings.
3) I'm having trouble even finding an enclosure for 3 large DC breakers
(Flex 1000 is the only thing I know of) and to get the enclosure close
enough is an issue too.
I just got off the phone with Tech support at Outback and they don't
seem to have any Rapid Shutdown gear ready.
Are inspectors actually requiring this yet, or because of the lack of
available UL listed products, can we take a pass on at least some of the
requirements? Another strategy the Outback tech thought of is to put
all the equipment into a shipping container and then its not in or on a
"building", and 690.12 doesn't apply.
--
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
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