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Getting odds and ends sorted in our new house....one noted item from the inspection was to move the breaker box ground from hot water line to cold water line. It appears someone did this because this ground won't reach the extra 10-12" to the cold line. It also looks like there's a ground going out and into the ground.

Can I replace the water line ground by shutting off the box main? Should I pull the exterior meter to be extra safe on this? Any harm in using 6-awg in place of the 4-awg wire for the ground on this?

Thanks!
 

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Getting odds and ends sorted in our new house....one noted item from the inspection was to move the breaker box ground from hot water line to cold water line. It appears someone did this because this ground won't reach the extra 10-12" to the cold line. It also looks like there's a ground going out and into the ground.

Can I replace the water line ground by shutting off the box main? Should I pull the exterior meter to be extra safe on this? Any harm in using 6-awg in place of the 4-awg wire for the ground on this?

Thanks!
I am not an electrician but i do a lot of electrical work on my rental properties.

To my knowledge, #6 wire is adequate for the ground. In our area, it must run from the breaker panel to within 5 feet of where the cold water line enters the house. There should also be a jumper from one side of the water meter to the other. The reasoning for the 5 foot rule is that someone could install pex in the cold water line which would break that ground. The reason for the jumper is that someone could remove the water meter, and without the jumper, you would lose the ground.

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Also, if you turn off the main you should be fine. Just understand that, even with the main off, there is still power in that panel on the wires that carry power to the main breaker. I usually make a cardboard cover to cover that area of the panel while i work on another area of the panel.

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First thing you need to determine is whether or not the conductor on the hot water pipe is a grounding electrode conductor or merely a metallic piping bonding conductor.
 

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The fat ground wire (grounding electrode conductor) from panel neutral to cold water pipe is sized depending on the electrical service size (amperage), I don't have the page of the NEC handy now. No. 4 copper is commonly used. There is no maximum distance that might affect where you install the panel.

An additional GEC from the panel to a ground rod is needed, is usually #6 copper, and never needs to be fatter. You need two 8' ground rods at least 6' apart unless, using specialized equipment, you can prove that one will suffice (25 ohm resistance with the earth).

The hot water plumbing must be bonded to the electrical ground (grounding electrode system), usually with a #4 bonding jumper (here bonding sections of metallic pipe) across the water heater hot and cold pipes in conjunction with the cold water pipe GEC.

The fat wire from hot water pipe to panel does not qualify as a grounding electrode conductor (not connected to a metal pipe within 5' of where the latter exits the house underground) but would qualify for bonding the hot water plumbing to the electrical system ground.

The water meter also needs a bonding jumper across it.

For a variety of reasons that are too complicated or tangential to explain in a treatise here, there may be current flowing on the GECs. To prevent a startling spark while installing wiring, we suggest using a set of automotive jumper cables to connect a pipe and a wire just prior to either unhooking or clamping the latter two.
 
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The fat ground wire (grounding electrode conductor) from panel neutral to cold water pipe is sized depending on the electrical service size (amperage), I don't have the page of the NEC handy now. No. 4 copper is commonly used. There is no maximum distance that might affect where you install the panel.

An additional GEC from the panel to a ground rod is usually #6 copper and never needs to be fatter. You need two 8' ground rods at least 6' apart unless, using specialized equipment you can prove that one will suffice (25 ohm resistance with the earth).

The hot water plumbing must be bonded to the electrical ground (grounding electrode system), usually with a #4 bonding jumper across the water heater hot and cold pipes.

The fat wire from hot water pipe to panel does not qualify as a grounding electrode conductor (not connected to a metal pipe within 5' of where the latter exits the house underground) but would qualify for bonding the hot water plumbing to the electrical system ground.

The water meter also needs a bonding jumper across it.
Allan - are two ground rods code everywhere? I ask because around here, suburban Philadelphia, i have never seen that. Typically i see 1 ground rod and #6 to the cold water pipe where it comes into the house. Is that cold water connection considered the second ground, or does code still require a second rod?

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Code now requires a single ground rod to be 25 ohms or less. If not, you install a second rod. There is no resistance requirement on the two rod system.

Because of the cost to test a single rod, it is cheaper (and quicker) to drive and connect the second rod.
 

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Code now requires a single ground rod to be 25 ohms or less. If not, you install a second rod. There is no resistance requirement on the two rod system.

Because of the cost to test a single rod, it is cheaper (and quicker) to drive and connect the second rod.
Yes, i understand that part, but i am wondering if the connection to the cold water pipe as it enters the home counts as a "second ground rod"?


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The 2 rods are considered as a single grounding electrode. The water pipe is another grounding electrode, not a rod.
 

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The 2 rods are considered as a single grounding electrode. The water pipe is another grounding electrode, not a rod.
Is that a newer requirement in the code? I ask because, although i have read that before, i have never actually come across it on any of my 11 properties nor any of the 20 or so properties i have worked on with friends of mine. I would assume that these homes, built in the 50s and 60s would be grandfathered, correct?

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Yes the 50/60s homes would be grandfathered, if they have there original panels. A panel change would shift the requirements to whatever date the panel was changed.

The 50/60s code was to use the water pipe electrode if it existed. The ground rod or other supplemental electrode was added in the 1978 code, IIRC.
 

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Is that a newer requirement in the code? I ask because, although i have read that before, i have never actually come across it on any of my 11 properties nor any of the 20 or so properties i have worked on with friends of mine. I would assume that these homes, built in the 50s and 60s would be grandfathered, correct?

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Depending on a few variables (soil type and moisture content of the soil) it the existing ground rod was installed in the 50's 0r 60's it is most likely corroded away and may be non-existent.
 

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If a ground rod is known to be less than 8' long buried either originally or having rusted away then it does not count as one of the required ground rods.

If a water pipe is known to run underground for fewer than ten feet exclusive of portions that are enameled on the outside or covered with a plastic sleeve then it does not qualify as a grounding electrode.

If a concrete rebar is known to have fewer than 20 feet embedded in concrete below grade inclusive of additional pieces of same joined with metal to metal contact using metal tie wires then it does not qualify as a concrete encased electrode sometimes called a Ufer grounding electrode.
 

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Thanks to all for all of the information. In myvrental properties the only ground that was originally installed was the connection too the cold water pipe as it entered the house. When i rehab these properties, i typically change out the service cable and the panel and add a ground rod and i also reconnect to the water supply. These have all passed inspection but i guess i should start adding a second ground rod as described here. Thanks again.

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Only one set of ground rods is needed for any one building. But if there are more ground rods being used for anything including TV antennas, all must be interconnected (bonded) using #6 copper run outdoors as much as possible.
 
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