Do I need further grounding of service panel?

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Old 09-12-18, 08:18 PM
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Do I need further grounding of service panel?

I've got a 200A service panel. It's got #4 copper coming out of the panel that runs to cast iron cold water pipe just above the panel. The copper also goes and is bonded (if that's the right word) to a natural gas line and to the cold water going into hot water heater. A #6 copper also comes out of panel and goes to two copper rods in ground outside my house.

I just cut out a section of the old cast iron to put in a new main water shut off valve, and I replaced with PVC.

I live in Idaho and they're following 2014 NEC.

Several questions:
1. Did the #4 copper to cold water pipe and the #6 to two copper grounding rods serve the exact same function, one a backup of the other, or do they do two separate functions?
2. Does the #4 copper going to gas line serve the same grounding function as the water pipe before I cut and replaced with plastic?
3. Do I need to jumper past the new plastic section, run a new #4 all the way from panel past the plastic, or do nothing because all is good?

I appreciate any answers to my questions,
pankesk
 
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Old 09-12-18, 08:41 PM
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1. The #4 copper and the #6 copper are both required as grounding electrode conductors. As wired, the #4 has a dual function, one function being the same as the #6 and the other function is to bond the gas plumbing and the balance of the cold water plumbing to the electrical ground.

2. The gas pipe is not a qualifying grounding electrode. The replacment of the outgoing water pipe with plastic eliminates the part of the function (the grounding electrode conductor function) of the #4 copper that duplicates the function of the #6. The other function performed by the #4 continues to be served.

3. The #4 continuing to the cold pipe at the water heater fulfils the needed bonding of the cold water system to the house electrical ground; no additional line to the panel is needed.

4. Add a jumper across the hot and cold pipes above the water heater.

5. The connection to the gas plumbing should be on the house side of the gas meter.

6. With no metal water pipe exiting the house underground, the requirement for a (the #4) grounding electrode conductor from the panel to the water pipe is eliminated. The existing #4 wire is now called a bonding jumper.
 
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Old 09-12-18, 08:46 PM
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1. Did the #4 copper to cold water pipe and the #6 to two copper grounding rods serve the exact same function, one a backup of the other, or do they do two separate functions?
Ground to water pipe grounds the water pipe to the grounding rod in case you have short to water pipe or lighting strike. Grounding rods grounds everything in your house that needs grounding.

2. Does the #4 copper going to gas line serve the same grounding function as the water pipe before I cut and replaced with plastic?
That grounds gas line for the same reason we ground water pipe.

3. Do I need to jumper past the new plastic section, run a new #4 all the way from panel past the plastic, or do nothing because all is good?
Cast iron? Household water line will not be a cast iron. Are you sure it is not the drain?
If section of water line was replaced with non-metalic pipe, it should be jumped.
 
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Old 09-13-18, 05:00 AM
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Allanj and lambition,
Thanks for your responses. I mis-spoke when I said cast iron. I meant galvanized.
 
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