Hi Ray,
Thanks for that information. I'm glad they covered that. I never
install more than a #4.
The question I'm still not sure of is weather or not we need to
ground the DC. I always have run a GEC to the DC. It would be great
if we didn't need to do so on the Sunny Islands especially, since
they are not set up for DC grounding.
Drake
At 01:51 PM 4/16/2013, you wrote:
Hi Drake;
Read down a bit more and 250.166(C) and (D) limit the size of the
GEC to #4 or #6 max., depending on what electrode is used.
This used to not be the case, and systems in the 90s had 4/0 cable
to a 5/8" electrode: which just like your 1/2" pipe example was
absolutely ridiculous.
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 4/16/2013 9:31 AM, Drake wrote:
So, in a standard battery system, with a charge control, ground
fault protection and an array, the DC system will likely need
grounding. If the DC system is grounded, then the battery cables
are grounded also.
In 250.166 (B) it says the grounding electrode conductor (GEC)
shall not be smaller than the largest conductor supplied by the system.
If the battery cables are "supplied by the system" doesn't this
imply that the GEC should be the size of the battery cable? This
is the logic that has led some inspectors to require a 4/0 copper
wire to be bonded to a 1/2" water pipe. This is, of course, technically absurd.
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