Hi
I have a client that wants the main service panel relocated to a detached garage and a subpanel in the house.
The Inspector is ok with the plan, HOWEVER he requires a very long ground wire run of 200-250ft (in a dedicated conduit) from the new location of the main service panel (200 AMP) at the detached garage to the cold water line stub in the basement floor at house. Long story short, doing this will be very expense because of the route the wire has to take. I could just do it but I feel its completely unethical to charge the homeowner for something that is not neccessary.
For context, this is a 1950s era home that once had a network of galvanized water pipes, but the pipes were all replaced with PEX when the pipes leaked, obstructed, and corroded. The only remaining metal is a stub of the copper cold water line to the water meter supply side and everything after the meter is PEX. The meter is in the basement of the house. There is no electrical continuity in the interior plumbing of the house.
My plan was to relocate the main service to the garage and ground it with grounding rods because there are no UFER grounds available on the garage slab. The garage was built around 2000 (not original). From the main service (in detached garage) a 4 conductor feeder will run to the subpanel in the house basement.
Currently the existing panel (100 AMP) at the house has two ground rods connected to the panel and a no. 8 Cu to the copper stub of the cold water line. I informed the Inspector the interior water lines are all PEX, non-metallic. I told the Inspector I will "keep" the ground wire from the subpanel to the cold water pipe, but he refuses to approve the plan unless I run a no. 4 Cu (possibly no. 2 Cu) ground wire from the detached garage to the cold water line in the house basement.
PLEASE correct me if I am wrong!!!!
It was my understand the NEC wants you to use the cold water pipe (if available) for these reasons: 1 > it provides an earth ground, 2> it grounds all the metallic water pipes to prevent a potential shock in the bath/shower/sink, if the plumbing was energized. But IF there are no metal pipes in the house, its just another grounding point. My interpretation is: Can the electrical system energize the plumbing? IF no, then the cold water pipe stub would NOT be required to be bonded. I am also not sure about NEC requiring the cold water line to be a "grounding point" vs grounding a metallic plumbing system.
Other electricians I reached out to in the State, don't believe the "main service ground to cold water pipe" from a detached garage is necessary either. If the property was on a well, my proposal would pass. IF an additional 200 amp service (from POCO) was "added" to the detached garage then a connection to the cold water pipe is NOT required by the Inspector. So IDK if the Inspector is just stuck in his ways and refuses to consider this specific situation or there is some safety issue I am not seeing. From past experience, Inspectors substantiate requirements. I suppose I will have to challenge him and ask for written documentation and his interpretation.
I cannot find specific wording in the NEC that says a "main service panel" in a detached building must be connected to a "cold water pipe" in a different building. My interpretation is if its available use it. But nowadays with plastic pipes frequently used in renos and new builds, I think the NEC needs to address this scenario.
Any advice or supporting arguments I can use in my next discussion with the Inspector is greatly appreciated.
Thank you
I have a client that wants the main service panel relocated to a detached garage and a subpanel in the house.
The Inspector is ok with the plan, HOWEVER he requires a very long ground wire run of 200-250ft (in a dedicated conduit) from the new location of the main service panel (200 AMP) at the detached garage to the cold water line stub in the basement floor at house. Long story short, doing this will be very expense because of the route the wire has to take. I could just do it but I feel its completely unethical to charge the homeowner for something that is not neccessary.
For context, this is a 1950s era home that once had a network of galvanized water pipes, but the pipes were all replaced with PEX when the pipes leaked, obstructed, and corroded. The only remaining metal is a stub of the copper cold water line to the water meter supply side and everything after the meter is PEX. The meter is in the basement of the house. There is no electrical continuity in the interior plumbing of the house.
My plan was to relocate the main service to the garage and ground it with grounding rods because there are no UFER grounds available on the garage slab. The garage was built around 2000 (not original). From the main service (in detached garage) a 4 conductor feeder will run to the subpanel in the house basement.
Currently the existing panel (100 AMP) at the house has two ground rods connected to the panel and a no. 8 Cu to the copper stub of the cold water line. I informed the Inspector the interior water lines are all PEX, non-metallic. I told the Inspector I will "keep" the ground wire from the subpanel to the cold water pipe, but he refuses to approve the plan unless I run a no. 4 Cu (possibly no. 2 Cu) ground wire from the detached garage to the cold water line in the house basement.
PLEASE correct me if I am wrong!!!!
It was my understand the NEC wants you to use the cold water pipe (if available) for these reasons: 1 > it provides an earth ground, 2> it grounds all the metallic water pipes to prevent a potential shock in the bath/shower/sink, if the plumbing was energized. But IF there are no metal pipes in the house, its just another grounding point. My interpretation is: Can the electrical system energize the plumbing? IF no, then the cold water pipe stub would NOT be required to be bonded. I am also not sure about NEC requiring the cold water line to be a "grounding point" vs grounding a metallic plumbing system.
Other electricians I reached out to in the State, don't believe the "main service ground to cold water pipe" from a detached garage is necessary either. If the property was on a well, my proposal would pass. IF an additional 200 amp service (from POCO) was "added" to the detached garage then a connection to the cold water pipe is NOT required by the Inspector. So IDK if the Inspector is just stuck in his ways and refuses to consider this specific situation or there is some safety issue I am not seeing. From past experience, Inspectors substantiate requirements. I suppose I will have to challenge him and ask for written documentation and his interpretation.
I cannot find specific wording in the NEC that says a "main service panel" in a detached building must be connected to a "cold water pipe" in a different building. My interpretation is if its available use it. But nowadays with plastic pipes frequently used in renos and new builds, I think the NEC needs to address this scenario.
Any advice or supporting arguments I can use in my next discussion with the Inspector is greatly appreciated.
Thank you
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