Supplemental Grounding Electrode

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romeo

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I hope I am not double posting.

If a ground rod is used to supplement a underground metal water pipe grounding electrode, must it meet the requierments of NEC 250.56, 25 ohms or less or a second ground rod ?

I believe so as required by 250.53(2)

I am getting a lot of argument saying that on a service upgrade that only 1 ground rod is required.
 
The ground rod is required to meet the 25 ohms or less where it is for supplemental protection or is the sole grounding electrode. For service upgrades we always pound in two rods a least 6' apart.
 
romeo said:
If a ground rod is used to supplement a underground metal water pipe grounding electrode, must it meet the requierments of NEC 250.56, 25 ohms or less or a second ground rod ?

I believe so as required by 250.53(2)
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Agreed.

I am getting a lot of argument saying that on a service upgrade that only 1 ground rod is required.
Click to expand...
Around here, all ground rods appear to have 25 ohms or less resistance at a glance. I don't think I've pounded two but once or twice. :D

But it is there to enforce, if you feel so inclined. :)
 
romeo said:
I am getting a lot of argument saying that on a service upgrade that only 1 ground rod is required.
Click to expand...


Romeo,

Only one ground rod would be required to supplement if by itself it had a resistance not over 25ohms. If you are unable to prove it is 25ohms or less , just drive an additional ground rod and you are code compliant.

ibew441dc
 
romeo said:
I hope I am not double posting.

If a ground rod is used to supplement a underground metal water pipe grounding electrode, must it meet the requierments of NEC 250.56, 25 ohms or less or a second ground rod ?

I believe so as required by 250.53(2)

I am getting a lot of argument saying that on a service upgrade that only 1 ground rod is required.
Click to expand...


I just did a Service Change yesterday, drove 2 rods @ 6.5' apart. I can't justify a meter to prove 25ohms or less! It would take a while to justify the cost. How many rods driven to equal cost. I agree that 1 additional rod is necessary if the first does not provide 25 ohm or less.

Tom

BTW, the old Service only connected to a metal water pipe(not copper), no rods ,nothing. It worked fine for 50 years+!
 
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