Grounding

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wmeek

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Is table 250-66(A) saying that when you bond metal water pipe and to ground rod you never have to have larger than #4 .

Thanks
 
Grounding

Is table 250-66(A) saying that when you bond metal water pipe and to ground rod you never have to have larger than #4 .

Thanks
 
So when you are grounding metal water pipe you have to use 250-66.
What about gas pipe grounding ,you use 250-122
 
Gas pipe is not permitted to be used as a grounding electrode. See 250.52(B)(1). Gas pipe may require bonding. See 250.104(B) for requirements.
 
A gas pipe is not suitable for use as a grounding electrode.

However, for the bonding requirements of gas piping, see 250.104(B). If it is likely to become energized, it should be bonded to the equipment grounding conductor of the circuit likely to energize it.
 
Say you have parallel service conductors. Say they are 350kcmil . How do you figure the size of wire to ground water pipe
 
Wmeek, are you talking about bonding the water piping or using it for a grounding electrode?

Does it meet the requirements of 250.52(A)(1)

If it is in fact a GE then see note 1 to table 250.66

Roger
 
wmeek said:
Say you have parallel service conductors. Say they are 350kcmil . How do you figure the size of wire to ground water pipe
Click to expand...


Add them together and look at 250.66. For example two sets of parallel 350's equals 700 kcmil's and requires a #2/0 CU GEC.
 
I was asking just for clarification, but you are correct that 250.66 would still be the correct table to use, so as Trevor says, with parallel 350's you would use "note 1" which would take you to the line 600 through 1100, this would give you a 2/0 copper or a 4/0 aluminum conductor.

Roger
 
I found that the service is parallel 3/0. Would you use table 5 to find the area square inch,of 3/0 and multiply by two. then take area square inch of that ,to determine what to use in table 250-66
 
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wmeek said:
I found that the service is parallel 3/0. Would you use table 5 to find the area square inch,of 3/0 and multiply by two. then take area square inch of that ,to determine what to use in table 250-66
Click to expand...

It would be more direct if you used Table 8 where you'd find that 3/0 is equal to 167800cm. Two of them equals 335600cm. Then go to 250.66.
The dimensions in Table 5 include insulation which would not be part of the calculation.

Jim T
 
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