WATER LINE BONDING

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dSilanskas said:
I've seen this done a lot with older homes around here. Was that in the code at some point? We don't do it around here anymore.
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John120/240 said:
Don't forget hot to cold bond at water heater.
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It was a local amendment, sometimes you just have to go along to get along.

How can bond hot to cold be a hazzard in one locality and not the next one

over. One city required greenie's on grounds. Go figure :huh:
 
Thanks for all the responses. It seems that with a commercial building served by a common water line (metallic) that is underground with individual waterline taps (also metallic) that run underground and up into each individual tenant space that have their own water meter, we are able to bond each individual tenant space panel board using 250.66 based on the feeder size. I still get a bit confused; i thought that with a main service disconnect that the water line main was to be used as part of the grounding electrode system using Table 250.66. I have read that most comments seem to state that Table 250.122 can be used as bonding the metallic water line even though the water line is not metallically isolated from the other tenant spaces. Article 250 is not always easy to understand.
 
ANY FURTHER COMMENTS ?

ANY FURTHER COMMENTS ?

TODD B. said:
Thanks for all the responses. It seems that with a commercial building served by a common water line (metallic) that is underground with individual waterline taps (also metallic) that run underground and up into each individual tenant space that have their own water meter, we are able to bond each individual tenant space panel board using 250.66 based on the feeder size. I still get a bit confused; i thought that with a main service disconnect that the water line main was to be used as part of the grounding electrode system using Table 250.66. I have read that most comments seem to state that Table 250.122 can be used as bonding the metallic water line even though the water line is not metallically isolated from the other tenant spaces. Article 250 is not always easy to understand.
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:(:(:(:(
 
250.104(1)

I almost went with 250.104(2) since it doesn't stipulate 'dwelling units'. But it says 'metallically isolated. Then I wonder if there's a common steel structure that, when bonded to, is part of the Grounding Electrode System. So back to your local GEC in that case.
 
I think the NEC lacks clarity on the issue you present. IMO, you should run one GEC full sized for the service conductors according to 250.66 to the closest water pipe and call it a day.
 
TODD B. said:
ANY FURTHER COMMENTS ? ]:(:(:(:(
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250.52 requires that any metal water pipe that is 10 feet long and in contact with earth to be used as part of the Grounding Electrode System. There is not but one exception to this requirement and this scenario does not fit that exception.

250.53 holds the requirements on how to install the Grounding Electrode System. 250.53(D) states that removable devices such as water meters cannot be part of the bonding path for the interior metal pipes that are required to be bonded by 250.104.

So far we have a metal water pipe that is in contact with earth which makes it an electrode. This electrode is to be bonded at the service disconnect which is the meter packs as outlined in your original post.

In post #5 you state that each tenant has its own water meter which 250.53(D) says cannot be part of the grounding path. If the water meter cannot be part of the grounding path then the requirement to bond the interior metal water pipe in 250.104 cannot use this path to bond the interior metal water pipe to the metal water pipe electrode.

This leaves two choices, one buy two clamps that will hold a bonding jumper sized to the service conductors as outlined in Table 250.66 and bond around every meter or simply follow the instructions outlined in 250.104(A)(2) and bond the interior metal water pipe using Table 250.122.

I find nothing hard or confusing about this scenario. Metal water pipe in contact with earth for 10 feet or more must be used as the electrode, 250.52. Interior metal water pipe installed in or attached to must be bonded 250.104. Two separate requirements two different methods to achieve these requirements. One cannot count for the other when there are removable devices such as water meters in the grounding path as outlined in 250.53(D).
 
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