Water GEC

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augie47

augie47

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Tennessee
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State Electrical Inspector (Retired)
'17 Code.
I have a building with a 1200 amp service with (3) 600 kcmil Cu.
Metal-Structural Frame building but hold down bolts were not boded to UFER
A #4 Cu was installed to the UFER at time of construction and is connected to the neutral in my service panel.
The steel is bonded with with a 250 kcmil cu per 250.104
I have a metallic underground water line on end of the building opposite the service gear.
250.68 notes building steel can be used to interconnect electrodes but my only electrode is my UFER with the #4 Cu.
My water line requires a 3/0.
Since I have the 250 kcmil boding jumper to the steel from the service can I connect my 3/0 from the water to the steel ?
 
If your stell is an electrode then the jumper to the water pipes is a bonding jumper. If it is not an electrode can you make a irreversible splice and extend the 3/0 from the steel to the water line?
 
as i read 250.68(C)(2) with my hold down bolts not bonded to the UFER, my steel can only be used to interconnect electrodes as it is not a grounding electrode conductor. My only electrode other than the water is the UFER connected by a #4.
 
augie47 said:
as i read 250.68(C)(2) with my hold down bolts not bonded to the UFER, my steel can only be used to interconnect electrodes as it is not a grounding electrode conductor. My only electrode other than the water is the UFER connected by a #4.
Click to expand...

I think you can use the steel as a GEC in your situation. 250.68(C)(2) after the comma in the first sentence says "or as a grounding electrode conductor". Interestingly, if it was a water pipe (C)(1) the pipe would have to be a GE before you could use it for this purpose.
 
augie47 said:
as i read 250.68(C)(2) with my hold down bolts not bonded to the UFER, my steel can only be used to interconnect electrodes as it is not a grounding electrode conductor. My only electrode other than the water is the UFER connected by a #4.
Click to expand...

If it's not an electrode you can still use it to interconnect other electrodes.
 
infinity said:
If it's not an electrode you can still use it to interconnect other electrodes.
Click to expand...
That's my understanding and I would be doing that (to a degree)/My 3/0 would connect to my water Grounding Electrode. My questions concerns the "other end"
I could easily connect the #4 from the UFER to the steel and I would have two electrodes bonded together by the steel which is allowed bt 250.68(C)(2) even if the steel does not qualify as grounding electrode conductor. My question comes from how then to connect to my service neutral. Presently my #4 UFER connects to the neutral but that connection is way undersized to be the link to the water electrode. With my 250 bond to steel I have a route to water but it seems that would be using the steel as grounding electrode conductor and it does not qualify.
It's too late to geta 3/0 to the UFER.
The only door I see open is to drive a ground rod and tie it to the steel with a 3/0 and connected a 3/0 to the ground rod and then let the steel tie the rod and water together.
That way there would be no "weak link" in the chain and I would only be using the steel to tie the two electrodes together.
 
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