250.53 e

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normbac

Senior Member
Is a ufer considered a suplemental electrode, does it fall under 250.53 E even though the verbage of ufer is not mentioned.
Always confused why bonding conductors to water and gas in a res. uses table 250.66 and a electrode conductor is maximum size of #6
 

rcarroll

Senior Member
A "ufer" or concrete encased electrode is not a supplemental electrode in 250.53. It is a required electrode if present per 250.50 & 250.52(3). A #6 copper is max to a ground rod, pipe or plate. 250.66(A).
 

jwelectric

Senior Member
Location
North Carolina
normbac said:
Is a ufer considered a suplemental electrode, does it fall under 250.53 E even though the verbage of ufer is not mentioned.
250.53(D)(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(7).

Yes I would say that if there was a CEE and a water pipe then this is all that is required.
 

haskindm

Senior Member
Location
Maryland
normbac said:
Always confused why bonding conductors to water and gas in a res. uses table 250.66 and a electrode conductor is maximum size of #6
A waterline may become energized and it and the bonding conductor would carry fault current until the overcuurent protective device opens, which could be hundreds of amps for a short period. If a 120-volt conductor faults to a grounding electrode with 25-ohms resistance, it will develop 4.8 amps. Does not take much of a conductor to carry 4.8 amps...
 

infinity

Moderator
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Location
New Jersey
Occupation
Journeyman Electrician
jwelectric said:
250.53(D)(2) Supplemental Electrode Required. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in 250.52(A)(2) through (A)(7).

Yes I would say that if there was a CEE and a water pipe then this is all that is required.

I agree the CEE might be a supplemental electrode if you're using a metallic water pipe as an electrode. If the building had a plastic water pipe then the CEE if present would be the only required electrode.

Larger than #6 to a ground rod would be useless since the rod can only do so much.
 
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