Hi there, please I need help understanding this section of the 2008 code, section 250.66 (A) : Where the grounding electrode conductor is connected to a ground rod, the grounding electrode conductor is not required to be larger than # 6 AWG Copper, is this means that I can use # 6 to bond a 300 A service with a 1 set of 350 KCMIL even if table 250.66 show #2 AWG electrode conductor for a 350 KCMIL ?
Grounding Electrode conductor (Ground Rod) section 250.66 (A)
- Thread starter O'donisR
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- Chapel Hill, NC
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- Retired Electrical Contractor
That is correct. A ground rod is only as good as a #6 so the NEC does not require larger than that even for a 3000 amp service. Be forewarned that many plans drawn by engineers will require a larger conductor-- The NEC does not
petersonra
Senior Member
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- Northern illinois
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- engineer
This is poorly stated IMO. the GEC connection to a ground rod does not have to be larger than #6. However, if you have other grounding electrodes present they may require a larger conductor.
For instance you might well have ground rods and an underground water pipe. You might have a #6 connection to the rods and a 2/0 to the water pipe.
For instance you might well have ground rods and an underground water pipe. You might have a #6 connection to the rods and a 2/0 to the water pipe.
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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And it does not have to be continuous as the picture shows.
Also if you go to the rod first then to the waterline the #6 rule goes away. Size to the service then.
Also if you go to the rod first then to the waterline the #6 rule goes away. Size to the service then.
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- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
250.66 states if it is the sole connection to the rod then the #6 is allow. If you have a water line that requires a #4 then you cannot run #6 to the rod if you jump from the rod to the water line. Naturally if you run a separate wire to the water line then a #6 is fine to the rods.
I wrote a proposal on this issue because technically the way it is written if you use two rods then you cannot run a #6 to the first rod since it is not the sole connection. The cmp accepted it and is in the draft-- I just proposed making electrode plural.
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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- Chapel Hill, NC
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- Retired Electrical Contractor
As I said earlier many engineers will not draw a #6 to the rod. If the plan gets accepted as such then it must be installed with the #2 as shown. The NEC only requires #6 in this case.
BTW. Hit CTRL and + or - , OR CTRL and the scroll wheel and you can enlarge the entire page of the forum to view the pic.
BTW. Hit CTRL and + or - , OR CTRL and the scroll wheel and you can enlarge the entire page of the forum to view the pic.
petersonra
Senior Member
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- Northern illinois
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what do you care if the wire is bigger than it needs to be anyway? it is just extra profit for you.
- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
I don't care but I didn't realize I said I cared or not. Since I don't do commercial work it is not an issue for me.
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jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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#2 required? Don't think so!
(A) Connections to Rod, Pipe, or Plate Electrodes.
Where the grounding electrode conductor is connected to
rod, pipe, or plate electrodes as permitted in 250.52(A)(5)
or (A)(7), that portion of the conductor that is the sole connection
to the grounding electrode shall not be required to be
larger than 6 AWG copper wire or 4 AWG aluminum wire.
- Location
- New Jersey
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- Journeyman Electrician
As Mike stated their wording gives you an out on using the #2 AWG.
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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- ESI, PI, RBO
Thanx and may require us to do so!
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I didn't try reading the entire part-- I agree wit choo.
I followed the rules but my riser was rejected due to size of electrode and I was forced to change the size up to a #2 using table 250.66 for a 350 KCMIL conductors. tomorrow I will meet the electrical reviewer again, that's why I added an extra note between the rods just in case he agree with me and allow me to use a #6 on this service. Thank you for the replays, I love this place !!
stickboy1375
Senior Member
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- Litchfield, CT
Since I don't do commercial work it is not an issue for me.
oh yeah...
its so ridiculous to run anything bigger than #6... The new company I work for only stocks #4 cu. so I'm stuck using that now...
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
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- ESI, PI, RBO
I didn't try reading the entire part-- I agree wit choo.
I'm on a roll. NOT! :roll:
hillbilly1
Senior Member
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- North Georgia mountains
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- Owner/electrical contractor
I had an inspector that was going to turn me down on a #4 bare cu I had run to a ground rod on a 2000 amp 480 volt service. (Didn't need it anyway, because I had cold water and building steel that both met the GEC requirement) When I told him it was legal, he said "show me!" I did, and he agreed, that I was correct and that he learned something that day!
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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- ESI, PI, RBO
That is how an inspector should act! Good for him!
stickboy1375
Senior Member
- Location
- Litchfield, CT
Actually, he shouldn't say something is not allowed unless HE can prove otherwise. :angel:
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