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silentsound
Water pipes bonded to grounding rod

I'm renovating my kitchen, which is next to the water heater and service panel. I came across a bare 6 AWG bonding connector in the ceiling connecting the hot metal water pipe from the water heater to the grounding rod outside. This seems a bit odd.

If this is to comply with 250.104(A), why not just run it to the service panel right next to the heater instead of to the rod on the other side of the house? And shouldn't this be bonded to the cold water pipe as well?

If the water pipes are being used as a GE per 250.52(A)(1), why is this connecting to the hot water feed from the heater? This is also greater than 5 ft. from the point of entrance.

House was built in 1982, but I can't find the NEC that far back.

Thanks.

Timothy Miller
Re: Water pipes bonded to grounding rod

Howdy i would bond it to the cold water pipes & add a jumper bond wire at the water meter. since the service panel is so close i would run the wire from it to the main water supply line be sure to install jumper at the service meter. The cold water supply is the best ground as it is laid into the ground- hot water pipe ground first has to rout the charge to the cold water pipes to the ground - a longer path.

NEC
Re: Water pipes bonded to grounding rod

Where is the main disconnect for the service? Is the neutral bonded to ground at that location? If so how? What grounding electrode conductors leave that location and where do they go? What are they connected to and how are they connected?

Timothy Miller
Re: Water pipes bonded to grounding rod

Howdy the main disconnect is usually the main circuit breaker in you electric service panel. The chance for death is very great when a novice is working in the panel. I caution you to not do this add items in your panel because of chance of shock- big kill ya right on the spot shock. i suggest you have an electrician out to run any additional ground wire as you will have to attach it into the panel to the ground an/or neutral buss and wish not to have you electrocute your self in the process. This is assuming your service is an electrical panel with circuit breakers and that you do not have any remote sub panels that you could mistake for the main panel.
The ground wires are ran to the neutral and or ground buss in the panel there can be several ground wires or just one usually #6 bare solid wire. if you know where you water meter is look and see if a copper wire is clamped to it as that is a grounding wire and if so is the wire clamped to the pipe on both sides of the meter so you have the best grounding. But seriously getting into a energized panel is for someone with knowledge and experience so heed my alert.....

silentsound
Re: Water pipes bonded to grounding rod

@Timothy: Bonding it to the cold water pipe is what I would have expected. The water heater was replaced, and I'm wondering if they just didn't reattach the bond correctly. The water meter is buried in a panel out by the curb, so the pipes there aren't easily accessible.

@NEC: The main disconnect is outside of the house. I don't feel comfortable opening that box up since there's no way to cut its feed without calling the power company. The neutral in the service panel, however, is bonded to the ground bus (the service panel was recently replaced by a licensed electrician). There is a GEC from the main disconnect panel to the grounding rod below it. IIRC, it is attached to the rod with a screw-type clamp.

So, to summarize, there are two GECs:

1. Hot water pipe -> #6 GEC -> Grounding rod
2. Ground bus bar -> Service feed ground -> Main disconnect outside -> #6 GEC -> Grounding rod

The gas pipe, CATV coax, and NID are also bonded to the grounding rod.

@Timothy: This house has a separate main disconnect in addition to the main breaker in the service panel. I'm pretty comfortable working in the service panel since I can flip the outside main disconnect to cut all power to it. There is a single service panel in this house.

It sounds like what I should do is attach that #6 GEC to the cold water pipe before the water heater instead and bond it to the hot water pipe from the heater. All this is further than 5 ft. from the water's service entrance (water heater is on one side of the garage, entrance is on the other side). The pipe is exposed all around, though, so it's easy to confirm there is no PVC in between, which I believe is the main reason for the 5 ft. rule.

NEC
Re: Water pipes bonded to grounding rod

All of the bonding and grounding needs to happen at the main disconnect, at one point, to all available "grounds" be it a ground rod or metal water piping.

From what you have described all of the grounds need to be isolated from the neutrals in the panel with the breakers.

A bonding jumper between hot and cold metal water piping at the water heater is fine.

The grounding/bonding needs to happen between the main disconnect bonding point to a point 5' from the water pipe entrance if the water pipe is metal.

Ernie_Fergler
Re: Water pipes bonded to grounding rod
silentsound wrote:

@Timothy: Bonding it to the cold water pipe is what I would have expected. The water heater was replaced, and I'm wondering if they just didn't reattach the bond correctly. The water meter is buried in a panel out by the curb, so the pipes there aren't easily accessible.

@NEC: The main disconnect is outside of the house. I don't feel comfortable opening that box up since there's no way to cut its feed without calling the power company. The neutral in the service panel, however, is bonded to the ground bus (the service panel was recently replaced by a licensed electrician). There is a GEC from the main disconnect panel to the grounding rod below it. IIRC, it is attached to the rod with a screw-type clamp.

So, to summarize, there are two GECs:

1. Hot water pipe -> #6 GEC -> Grounding rod
2. Ground bus bar -> Service feed ground -> Main disconnect outside -> #6 GEC -> Grounding rod

The gas pipe, CATV coax, and NID are also bonded to the grounding rod.

@Timothy: This house has a separate main disconnect in addition to the main breaker in the service panel. I'm pretty comfortable working in the service panel since I can flip the outside main disconnect to cut all power to it. There is a single service panel in this house.

It sounds like what I should do is attach that #6 GEC to the cold water pipe before the water heater instead and bond it to the hot water pipe from the heater. All this is further than 5 ft. from the water's service entrance (water heater is on one side of the garage, entrance is on the other side). The pipe is exposed all around, though, so it's easy to confirm there is no PVC in between, which I believe is the main reason for the 5 ft. rule.

According to NEC 250.52{B} Metal underground gas piping or aluminum electrodes are not permitted as grounding electrodes.

Timothy Miller
Re: Water pipes bonded to grounding rod

Howdy again, the grounding to a gas line is a big no no as you never want to risk a short to go to ground and have any chance of igniting gas.
I was assuming your water meter was in the house no need to add a jumper at you water meter.
Adding a jumper from the hot water to the cold water pipe at the water heater is also a grounding improvement.

Shaun
Re: Water pipes bonded to grounding rod

I believe the op is saying the gas pipe is grounded not that systems are grounded to the gas line. Interior gas piping is required to be grounded in Mass. if the system uses Csst (corrugated stainless steel tubing).

canuk
Re: Water pipes bonded to grounding rod
Quote:

Adding a jumper from the hot water to the cold water pipe at the water heater is also a grounding improvement.

Curious ------- what benefit is there to grounding the hot and cold water branch lines within the house ?

silentsound
Re: Water pipes bonded to grounding rod
NEC wrote:

From what you have described all of the grounds need to be isolated from the neutrals in the panel with the breakers.

I'm fairly certain that's how it is, but I'll verify when I open the service panel up again.

NEC wrote:

A bonding jumper between hot and cold metal water piping at the water heater is fine.

The grounding/bonding needs to happen between the main disconnect bonding point to a point 5' from the water pipe entrance if the water pipe is metal.

Water pipes are metal, but bonding to them 5' from the service entrance will be rather hard. It was never bonded there when the house was built/inspected (any idea when the 5' feet rule was added?). As a start, seems I'd already be better off moving that GEC to the pre-water-heater cold water pipe and using a bonding jumper between cold and hot.

Ernie_Fergler wrote:

According to NEC 250.52{B} Metal underground gas piping or aluminum electrodes are not permitted as grounding electrodes.

Timothy Miller wrote:

Howdy again, the grounding to a gas line is a big no no as you never want to risk a short to go to ground and have any chance of igniting gas.

Shaun wrote:

I believe the op is saying the gas pipe is grounded not that systems are grounded to the gas line. Interior gas piping is required to be grounded in Mass. if the system uses Csst (corrugated stainless steel tubing).

Correct, the gas pipe is bonded to the grounding rod/electrode per NEC 250.104(B).

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