Water pipe grounding

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Old 03-23-14, 05:45 AM
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Water pipe grounding

Our house was built in the 1950’s. We replaced the galvanized pipe from the well to the house with plastic pipe. We replaced the 120 volt overhead power into the house with 240 volt underground. The old grounding system consisted of a rod in the ground at the house. The new grounding system consists of two 8 foot rods seven feet apart at the meter and two 8 foot rods seven feet apart at the fused disconnect at the house. The water pipes in the house are copper. We could not see anywhere in the house where the water pipes are grounded. Do we need to connect the house ground to the water pipes?
 
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Old 03-23-14, 06:01 AM
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Yes, the copper plumbing system needs to be "grounded". The same method as before is used although this time the connection to the water pipe does not need to be within 5' of where the (now plastic) pipe exits the house underground. Also, this time the connection is preferably made "after" the water meter.

The new fat wire (now called a bonding jumper) from the plumbing system may need to be larger than #6 copper depending on the potential amperage of the electrical service (more correctly the size of the service conductors from the utility). I forget the threshold. It goes all the way to the panel neutral bus unless it first reaches another fat wire (grounding electrode conductor) of at least the same size from a ground rod and going back to the panel.

If the meter and its two ground rods are at the house (as opposed to at a pole or detached garage) then those ground rods need to be interconnected with the ground rods at the panel using #6 copper wire.
 

Last edited by AllanJ; 03-23-14 at 06:21 AM.
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Old 03-28-14, 06:50 AM
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Thanks. I will run #4 copper about 5 ft. from the ground bar on the panel to the nearest copper water pipe.
 
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Old 03-28-14, 12:22 PM
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You should also run a short jumper past any point of electrical discontinuity in the water piping. The water heater is typically a location where this needs to be done.
 
 

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