GEC sizing

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c_picard

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Evenin' folks,
Here's a simple question for y'all....

Suppose there is a GEC run to a ground rod, which then continues to a second ground rod(required because of that pesky <25ohm rule). Is that GEC still not required to be larger than 6AWG? Or does that exception only apply if the GEC only goes to a SINGLE ground rod?
For my example, lets' use a 200A service, with no other available GE's

thanks,
Charles
 
c_picard said:
Suppose there is a GEC run to a ground rod, which then continues to a second ground rod(required because of that pesky <25ohm rule). Is that GEC still not required to be larger than 6AWG? Or does that exception only apply if the GEC only goes to a SINGLE ground rod?
Click to expand...
Charles, the section between the service disco and the first rod is the GEC; the section to the second rod is a jumper. Neither is required to be larger than #6 as long as no other electrodes (such as piping or building steel) use these conductors.

Even for a 2000a service, and even if the rods are the only electrodes, the #6 is large enough.
 
I agree with Larry. And would add that the GE conductor is only required to be continuous to the first rod.
 
c_picard said:
Suppose there is a GEC run to a ground rod, which then continues to a second ground rod(required because of that pesky <25ohm rule).
Click to expand...

There is no such requirement. A lot of folks think there is but if you read 250.64(C) it only applies to the GEC. I think the trouble comes from the definition of GEC in Article 100;
"The conductor used to connect the grounding electrode(s)",
that and some rather not so good wording and too much bouncing around code sections in Article 250.

c_picard said:
Is that GEC still not required to be larger than 6AWG? Or does that exception only apply if the GEC only goes to a SINGLE ground rod?
Click to expand...

All the conductors in the electrode system that aren't the GEC are bonding jumpers. 250.53(C) points to 250.66 for bonding jumper size.
 
physis said:
All the conductors in the electrode system that aren't the GEC are bonding jumpers. 250.53(C) points to 250.66 for bonding jumper size.
Click to expand...
Yes... and 250.66(F) states, "The grounding electrode conductor shall be sized for the largest grounding electrode conductor required among all the electrodes connected to it."
 
That's interesting that the GEC does not have to be continous all the way to the 2nd rod.I've always made it all one peice.
Can (2) #6 Bare be terminated under (1) Ground Rod Clamp at the First Rod?
Or are (2) Ground Rod Clamps Required at the 1st Rod?
 
jap said:
Can (2) #6 Bare be terminated under (1) Ground Rod Clamp at the First Rod?
Or are (2) Ground Rod Clamps Required at the 1st Rod?
Click to expand...

Ground rod clamps are not designed to connect multiple wires under a single clamp, so you would need to use 2 clamps.

Chris
 
SI-2173m.jpg


Edit: Don't mind this post, I'm just trying to remember how to do images.
 
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