DIYbanter - View Single Post

wrote:
On Wed, 12 Jan 2005 19:46:39 -0600, zxcvbob

If he ran a 100A feeder to the garage panel, the grounding wire is at
least 6 gauge, and maybe 4. IIRC, #6 is the largest wire you are ever
required to use to connect a ground rod to the grounding electrode system.

thought 6 was small, so went looking. 2002nec table 250.66 for copper
3/0 is the largest, and for aluminum 250 kcmils. They are a little
bigger than 6awg.

(I wish I could find my code book, even though it's 10 years old.) I
don't think NEC ever requires a conductor that big to connect a ground
rod to the electrode grounding system. In fact, I think there is a
specific exception that says it never has to be larger than #6 copper or
#6 copper-clad aluminum. It probably does require an equipment
grounding conductor (ground wire), or grounded conductor (neutral wire)
that big for 200A or larger feeder circuits, but that's not what we are
talking about.

I would probably drive a ground rod at the garage. I don't know if it
is required or not (but I think it is.) Since there's a seperate
grounding wire already, I don't think it's all that important.

Good point, it doesn't seem to be anything against driving another
grounding rod, but then, if he wired it correctly, nothing seems to
indicate he needs to.

Bob