Is it okay to ground the service panel downstream of the copper supply plumbing primary isolation valve? I know it cant be done downstream of a dielectric connector. Thanks.
Mark,
I’ve always seen a jumper wire in those cases around the valve even when it’s not a dielecric connector, but can’t say for sure what’s required.
Paul-Marc
Mark, I think its only recommended that it be upstream of the isolation valve for situations when someone might need to work on/replace the valve. But I don’t think it’s actually required to be upstream unless it’s the dielecric kind. If it’s a meter it should be upstream, but that’s different. Otherwise, I think it’s just to be as close to the point of entry as possible. Wait and see what others think…
Paul-Marc
The question needs clarity. Are you asking if it is alright to bond the metal water pipe downstream for the point of entry? Yes
Let me explain
If the metal pipe has contact with earth for at least 10 feet then the metal pipe must be used as the grounding electrode. In the newer codes the point of attachment of the grounding electrode conductor must take place within the first five feet where the pipe enters the building. This is required by 250.52(A)(1) of the NEC
The interior metal water pipe is also required to be bonded. This is a requirement found in 250.104(A) of today’s NEC. This bonding can be done from any grounding electrode such as the ten feet that is in contact with earth. To accomplish this most will bond around such items as meters, filters and such other removable devices.
If there is no metal pipe in contact with earth and the interior pipes are metal then the 250.104(A)(1) requirement to bond the pipe only has to be accessible.
The requirement to bond around nonmetallic fittings and dielectric fittings was removed from the code in the mid 1980s. The requirement to make and keep a metal water pipe was added to the code when the three wire receptacle was introduced. In order to change out the two wire receptacle to a three wire receptacle could be accomplished by simply extending the conductor from the green screw on the three wire receptacle to a metal water pipe.
I have a neat little Power Point Presentation that covers this and shows the requirements from codes gone by if someone would like to see it.
The first attachment is from the 1975 cycle section 250-80 and the second attachment is from the 1984 cycle and still section 250-80.
Notice that the requirement to keep metal water pipes electrically continuous was removed.
