Grounding Electrode System Question

[ActionDave]

I had my own question about this. I’ve always thought the ground rods were doing the “grounding” and the reason for running the wire to the pipe was “bonding“ so that the pipes are at the same potential as the rods and lightning will not travel through the dirt and up into the house and through the pipes.

In a situation with a main panel and a sub panel, is it ok to run a wire from the sub panel ground bus because it makes sense geographically (in cases where sub panel is closer to water pipe) or must the pipe be connected to the main panel where the neutral/ground bond occurs?

I'm not picking on you but I will use your post as more evidence why I am solidly against this trend in the electrical industry and the NEC to use the word bonding instead of grounding and equipment grounding.

As far as connecting a water pipe that qualifies as a grounding electrode it has to be bonded at the service, 250.24. You can jumper from one electrode to the next as long as your wires are sized appropriately 250.64, 250.68.

 

[infinity]

250.53(D)(1) Continuity of grounding path ...... shall not rely on water meter or filtering devices or similar equipment. Thus anything that would or could break the continuity of the grounding path by removal or high impedance connections like a water meter could be interpreted as requiring the connection take place on the Street side of water main (or where it exits the structure). But a means of bonding jumper bypassing meter or other nonconductive or potentially high impedance connections needed to meeting bonding requirements.

That says nothing about "street side of the water main", those words do not exist in the NEC. The requirement is that the connection be within 5' of where the pipe enters the building. If there is something that can interrupt the continuity between the connection and the entry point then a bonding jumper is required. Can we agree that the part in bold is your opinion not what it says in the NEC?

 

[electrofelon]

I'm not even sure what "street side of water main" means. Street side of water meter would make a little more sense, but it still doesn't say that. A bonding jumper is typically placed around the water meter.

 

[Fred B]

That says nothing about "street side of the water main", those words do not exist in the NEC. The requirement is that the connection be within 5' of where the pipe enters the building. If there is something that can interrupt the continuity between the connection and the entry point then a bonding jumper is required. Can we agree that the part in bold is your opinion not what it says in the NEC?

Correct, just indicating code can be interpreted to mean or justify the "idea" of "street side of water main" (what ever that means, not my words). Debate has occurred in regards to Point of Bonding, does GEC hit the "street side" first, then jumper back to go over interrupting point to bond the remaining pipe, or can GEC hit house side first then jumper over interruption to bond the water pipe used as a grounding electrode.

 

[infinity]

Correct, just indicating code can be interpreted to mean or justify the "idea" of "street side of water main" (what ever that means, not my words). Debate has occurred in regards to Point of Bonding, does GEC hit the "street side" first, then jumper back to go over interrupting point to bond the remaining pipe, or can GEC hit house side first then jumper over interruption to bond the water pipe used as a grounding electrode.

Not sure why there ever was a debate (I have heard connect before the meter on many occasions) the wording is clear, connect the GEC within 5' of where the pipe enters. If there is something that can be removed like the water meter than a jumper is required.

 

[LarryFine]

Debate has occurred in regards to Point of Bonding, does GEC hit the "street side" first, then jumper back to go over interrupting point to bond the remaining pipe, or can GEC hit house side first then jumper over interruption to bond the water pipe used as a grounding electrode.

Either is acceptable.

 

[Doc13067]

I'm not picking on you but I will use your post as more evidence why I am solidly against this trend in the electrical industry and the NEC to use the word bonding instead of grounding and equipment grounding.

As far as connecting a water pipe that qualifies as a grounding electrode it has to be bonded at the service, 250.24. You can jumper from one electrode to the next as long as your wires are sized appropriately 250.64, 250.68.

Thanks for your reply. But I’m not talking about using it as an electrode in this scenario. I’m assuming my 2 ground rods are the electrodes and I’m connecting the water pipe to the metal devices throughout the house. Therefore I’m bonding the water pipes to make them be at the same potential as everything else and then one GEC connects the pipes and everything else to the 2 electrodes.

So my question was is my whole premise wrong? Should I be confirming if the pipes are suitable for use as an electrode and then treating them as a 3rd electrode and connecting them to the main disconnect? Or since I drive 2 ground rods can I consider those the only electrodes and simply bond the pipes (connect them to a ground bus in any sub panel)?

 

[roger]

If the water piping qualifies as an electrode your answer is the first sentence of Part III of article 250. If it doesn't qualify it simply has to be bonded per 250.104 and this can be achieved with a branch circuit EGC as small as a #14 if the branch circuit that is likely to energize it is a 15 amp circuit.

Roger

 

[Fred B]

If the water piping qualifies as an electrode your answer is the first sentence of Part III of article 250. If it doesn't qualify it simply has to be bonded per 250.104 and this can be achieved with a branch circuit EGC as small as a #14 if the branch circuit that is likely to energize it is a 15 amp circuit.

Roger

My point is unless you can verify that the water line does indeed "Qualify", can you even call it a grounding electrode? Seen many cases where someone has changed out the underground portion of metal waterline to a plastic one, usually corrosion or breakage, thus I see the need for confirmation. Either way it would need bonding. I find its easier to just drive 2 rods and be done with it and then just bond along with the other items as you say related to 250.104

 

[infinity]

My point is unless you can verify that the water line does indeed "Qualify", can you even call it a grounding electrode? Seen many cases where someone has changed out the underground portion of metal waterline to a plastic one, usually corrosion or breakage, thus I see the need for confirmation. Either way it would need bonding. I find its easier to just drive 2 rods and be done with it and then just bond along with the other items as you say related to 250.104

Are you saying that it's possible that the pipe has been replaced with a nonmetallic pipe right up to the point where it enters the building but not extended into the building where the replacement pipe would be visible?

 

[Fred B]

Are you saying that it's possible that the pipe has been replaced with a nonmetallic pipe right up to the point where it enters the building but not extended into the building where the replacement pipe would be visible?

Exactly. Guess to lazy to drill a new hole in concrete wall. Seen many times. Public water seemed to be the worst, replacing water lines on public side but they don't enter the house. One stated "that is the homeowners responsibility we don't do that". Seen grounds comprised as a result and HO was unaware of any issue.
Guess this might validate another poster's comment on the validity of grounding, as I'm unaware of any untorend results of the loss of the grounding electrode in this case.

 

[roger]

My point is unless you can verify that the water line does indeed "Qualify", can you even call it a grounding electrode?

If I were an inspector I would have every right to have someone prove it does or doesn't.

Roger

 

[Doc13067]

My point is unless you can verify that the water line does indeed "Qualify", can you even call it a grounding electrode? Seen many cases where someone has changed out the underground portion of metal waterline to a plastic one, usually corrosion or breakage, thus I see the need for confirmation. Either way it would need bonding. I find its easier to just drive 2 rods and be done with it and then just bond along with the other items as you say related to 250.104

I’m on the same page. I’m looking for proof that we are wrong on this but it seems like you can’t go wrong. Roger

 

[Doc13067]

If the water piping qualifies as an electrode your answer is the first sentence of Part III of article 250. If it doesn't qualify it simply has to be bonded per 250.104 and this can be achieved with a branch circuit EGC as small as a #14 if the branch circuit that is likely to energize it is a 15 amp circuit.

Roger

Awesome thank you for the clarification Roger.

 

[infinity]

Exactly. Guess to lazy to drill a new hole in concrete wall. Seen many times. Public water seemed to be the worst, replacing water lines on public side but they don't enter the house. One stated "that is the homeowners responsibility we don't do that". Seen grounds comprised as a result and HO was unaware of any issue.
Guess this might validate another poster's comment on the validity of grounding, as I'm unaware of any untorend results of the loss of the grounding electrode in this case.

So what's the harm in connecting the GEC within 5' as required for use as a GEC? Even if the pipe has been replced and is less than 10' in the earth you have complied with the water pipe system bonding requirement.

 

[Doc13067]

If the water piping qualifies as an electrode your answer is the first sentence of Part III of article 250. If it doesn't qualify it simply has to be bonded per 250.104 and this can be achieved with a branch circuit EGC as small as a #14 if the branch circuit that is likely to energize it is a 15 amp circuit.

Roger

Roger, I read the first sentence in Part 3 but I’m still unclear. I made a diagram with 2 scenarios. Could you please take a look and tell me if scenario 1 is ok or if it has to be scenario 2?

 

[ActionDave]

Roger, I read the first sentence in Part 3 but I’m still unclear. I made a diagram with 2 scenarios. Could you please take a look and tell me if scenario 1 is ok or if it has to be scenario 2?

Does the water pipe in your illustration qualify as an electrode or is it just part of a metal piping system?

 

[Doc13067]

Does the water pipe in your illustration qualify as an electrode or is it just part of a metal piping system?

I know it is metal and runs for more than 10 feet underground but Im unsure if there are any other factors needed to make it qualify so I’m putting in 2 ground rods to be sure. Would my scenario 1 only be ok if the pipe does not qualify?

 

[ActionDave]

I know it is metal and runs for more than 10 feet underground

Then it qualifies as a grounding electrode and 1 would be required.

but Im unsure if there are any other factors needed to make it qualify so I’m putting in 2 ground rods to be sure.

Qualifying water pipes always require a supplemental grounding electrode, if the supplemental electrode is a ground rod then the 25 ohm rule means you drive a second rod.

Would my scenario 1 only be ok if the pipe does not qualify?

1 or 2 is ok if the water pipe is not a grounding electrode.

 

[ptonsparky]

Late comer.
Backing up to where the grounding electrode conductor to rods can be connected, In the areas I have worked, I would venture to say that all were connected at the service drop POA during the original installation of power prior to the late 60s. It did not matter where the meter was located.