Sub Panel Ground question

[nate379]

I had an electrician come by the other day and put in my 2 ground rods for my shed ($50 and the rotary hammer got them in in under 15 mins... would have spent all day with a sledgehammer!)

So now I need to wire them. Building has 30 amp power, do I run a 10 gauge ground wire, or does it need to be the same as the house which is either 4 or 6 gauge?

 

[Aceman]

I use #4 to the rods for ALL panel sizes.

 

[nate379]

I am looking on Table 250-66 in the NEC, I think that is the correct one to look (NEC is hard to decifer!)

It is saying #8 for #2 wire or smaller.

I only have about 25ft to run so not the end of the world to buy larger wire, but no sense in wasting money either if I don't need to.

 

[Joe From NY]

Go to this document and use the "find" feature of your PDF viewer to look for grounding requirements. It is the draft of the 2011 National Electrical Code.

http://www.google.com/url?sa=t&source=web&cd=12&ved=0CCAQFjABOAo&url=http%3A%2F%2Fgalileo.phys.virginia.edu%2Fresearch%2Fgroups%2Fhep%2Faag%2F70-A2010-ROPDraft.pdf&rct=j&q=%22national%20electrical%20code%22%20filetype%3Apdf&ei=mmqqTJ6GGYP78AbNq9z_DA&usg=AFQjCNEpTvS5jEvwO8KSkjOddV8JXe6siA&cad=rja

 

[Joe From NY]

I am looking on Table 250-66 in the NEC, I think that is the correct one to look (NEC is hard to decifer!)

It is saying #8 for #2 wire or smaller.

I only have about 25ft to run so not the end of the world to buy larger wire, but no sense in wasting money either if I don't need to.

Damn, by the time i found the document online, you already had a copy. oh well.

 

[sberry]

I beleive its number 8 for 100 a and under.

 

[Aceman]

Take a look at 250.64(B).

 

[2LTim]

The next time you need to sink a ground rod, give this a try. Dig a hole 8" in diameter by a foot deep. Fill it with water, then take your ground rod and push it into the ground in the middle of the hole with your hands. Take it down a couple of feet then pull it back up roughly half way. Keep working it up and down and in about three minutes, you will have it in as deep as you need it. Just keep water in the hole. If you hit rocks, just move your location a bit one way or the other. I have been sinking them this way for years!
Tim

 

[Norcal]

Please note the requirements of 250.64( B ).

(B) Securing and Protection Against Physical Damage.
Where exposed, a grounding electrode conductor or its enclosure
shall be securely fastened to the surface on which it
is carried. A 4 AWG or larger copper or aluminum grounding
electrode conductor shall be protected where exposed to
physical damage. A 6 AWG grounding electrode conductor
that is free from exposure to physical damage shall be permitted
to be run along the surface of the building construction
without metal covering or protection where it is securely
fastened to the construction; otherwise, it shall be in
rigid metal conduit, intermediate metal conduit, rigid nonmetallic
conduit, electrical metallic tubing, or cable armor.
Grounding electrode conductors smaller than 6 AWG shall be
in rigid metal conduit, intermediate metal conduit, rigid nonmetallic
conduit, electrical metallic tubing, or cable armor.

This is a copy & paste from the 2008 NEC.