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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