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Residential bonding of water pipe/Pex

33671 Views 27 Replies 8 Participants Last post by  brian john
I just had a electrical inspection today. Unfortunately i was unable to be there due to recent heart failure. My general contractor who is familiar with electrical met with the inspector. He called out that the water pipe which enters through the side of the foundation to be bonded. The entire house was ran in plastic (PEX). The metal pipe coming through the foundation is only 8-12" long where it immediately turns to PEX. I am having a hard time believing that this metal pipe is required to be bonded when there are no electrical circuits that come in contact with it and the fact it is only 8-12" long. Having to bond this water pipe requires running at least 60 feet of bare copper to the other side of the house to the panel. He is also requiring a ugly access hatch for the ground clamp which would be highly visible in a guest room. The inspector is a new young guy. Is he correct in calling out this correction? It seems to me it would act more as a supplemental grounding if done rather than just a bond.
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Up here the code says "where a metal water piping system is installed....."
Doesn't seem to me that metal stub qualifies as a piping system.
code ref (for the other canucks) 10-406(2)
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A cold water pipe is considered a Grounding Electrode and it is to ground the electric system, not so much the water pipes.

250.4(a)(1) Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

250.52(a)(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0m or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulation joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductor(s) or jumper(s), if installed.

If metallic piping in the home, it should all be bonded together so they all have the same impedance . This includes- hot water pipe, cold water pipe, sewer pipe, gas pipes.

I was once in a home where i was reading 115v between the cold water handle in the shower and the floor drain. Someone had cut the waste stack and replaced a section with PVC. By chance, an old rag wire had enough insulation rubbed off that it made direct contact with the galvanized waste stack. The occupants where getting shocked every time they showered or washed their hands in the bathroom. Scary to think that at any moment they could have cooked themselves to death while in the shower.
 

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Discussion Starter · #11 ·
The metal pipe is metal underground from stub continuously to outside where it connects with the city supply. The inspector did not cite code references. He did not mention if he wanted it bonded for grounding electrode purposes or that it was likly to become energized. In Seattle they are no longer giving contractors hand written corrections
 

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The metal pipe is metal underground from stub continuously to outside where it connects with the city supply. The inspector did not cite code references. He did not mention if he wanted it bonded for grounding electrode purposes or that it was likly to become energized. In Seattle they are no longer giving contractors hand written corrections
Inspector is correct.
 

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The metal pipe is metal underground from stub continuously to outside where it connects with the city supply. The inspector did not cite code references. He did not mention if he wanted it bonded for grounding electrode purposes or that it was likly to become energized. In Seattle they are no longer giving contractors hand written corrections
Sorry if I missed this, but where are you getting your system ground from?
I always get it from the city water pipe, when there is one.
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The metal pipe is metal underground from stub continuously to outside where it connects with the city supply. The inspector did not cite code references. He did not mention if he wanted it bonded for grounding electrode purposes or that it was likly to become energized. In Seattle they are no longer giving contractors hand written corrections
You need to do it. I believe it's 250.104.

ETA, see the below post for the correct section.
 

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The metal pipe is metal underground from stub continuously to outside where it connects with the city supply. The inspector did not cite code references. He did not mention if he wanted it bonded for grounding electrode purposes or that it was likly to become energized. In Seattle they are no longer giving contractors hand written corrections
Then 250.52(a)(1) Metal Underground Water Pipe does apply and it is considered an electrode conductor.
 

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Btw I use #4 copper for all bonding, grounding and ground rods. Yes it costs more, Yes my customers pay for my convenience of only having one type of wire on the truck and the ducking Kenny Clamps I have to use.. I hate Kenny clamps.
 

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There are 2 ground rods and the gas line is also bonded. The electrical panel and grounding system were existing.
In that case, I'll stick with post #3.
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