gas line bonding/grounding

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erickench said:
The person who started this thread would have to tell us more.

1) Is there a dielectric coupling?
2) If so then where is this 9 volts coming from? Utility or premises side?
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Most of the time premises side. That is where risk of energizing it is higher. If OP determines it is utility side then he needs to call gas company back and tell them it it their problem. If it is utility side it is probably originating from another premises system. Just because it is standard to install dielectric fitting at every service doesn't mean it can't be jeapordized or bypassed somehow.
 
If there is a dielectric coupling then there would have to be a bonding connection on the utility side. This is clearly a violation. The voltage would be caused by voltage gradients(shells) in the earth.

If there is no dielectric coupling then the entire pipe is being used as an electrode which has to be corrected by the gas company. Again the voltage would be caused by voltage gradients in the earth.
 
erickench said:
If there is a dielectric coupling then there would have to be a bonding connection on the utility side. This is clearly a violation. The voltage would be caused by voltage gradients(shells) in the earth.

If there is no dielectric coupling then the entire pipe is being used as an electrode which has to be corrected by the gas company. Again the voltage would be caused by voltage gradients in the earth.
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Voltage shells come from an energized conductor in the earth, one that has insulation issues. There has to be an abnormal situation someplace to cause these shells. Like I said it is more likely stray voltages are originating on premises side of gas service. Making it very likely gas man comes to turn on service - reads voltage on piping and assumes it is premises problem - most of the time this assumption will be accurate.
 
erickench said:
Like I said we need more information from the person who started this thread.
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OP wanted to bond to water pipe and or electrical service. I mentioned in post #2 first thing is to find the source of voltage. Just bonding it, whether right or wrong, doesn't necessarily make the problem go away - it might just mask the problem.
 
NFN but sounds like NEV

NFN but sounds like NEV

kwired said:
OP wanted to bond to water pipe and or electrical service. I mentioned in post #2 first thing is to find the source of voltage. Just bonding it, whether right or wrong, doesn't necessarily make the problem go away - it might just mask the problem.
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If there is an intentional bonding on the premises side, and/or there is appliance tool with a case ground that is fed by a gas pipe, wouldn't this mean that the gas pipe would manifest whatever Neutral to Earth Voltage was about. I would see if the voltage is about the same and varies similarly to any measured neutral to earth voltage.

Around here the gas company and the electric company are the same animal so you can tell 'em its their problem.

On the electrolysis thing, every metal pipe water service I've ever seen is grounded to the metal water pipe deliberately on the utility side of the water meter. Out here in the hinterlands we use electrodes cause the water pipe is all plastic.

Admit I'm confused between the portions of the code that seem to say you can't ground/bond to metal piping systems and assertions that you must use metal water piping if present, e.g.:

250.52(B) Not Permitted for Use as Grounding Electrodes.
The following systems and materials shall not be used as grounding electrodes:
(1) Metal underground piping systems
(2) Aluminum

and kwired:

Water companies can complain all they want about current on the lines - it will happen anyway which is one reason why NEC wants metal water piping to be used as grounding electrode if it is present. Water piping will usually have lower resistance than any made electrodes - that is just the way they naturally are.

now the second contention doesn't have citation, but it jibes with every urban installation I've ever seen.

I also see that it is ambiguous whether what 250.52(B) is saying is that you have to install a separate electrode or you cannot bond to metal underground piping systems.

I think this worthy of fleshing out some more.

thanks,

brian
 
archibald tuttle said:
If there is an intentional bonding on the premises side, and/or there is appliance tool with a case ground that is fed by a gas pipe, wouldn't this mean that the gas pipe would manifest whatever Neutral to Earth Voltage was about. I would see if the voltage is about the same and varies similarly to any measured neutral to earth voltage.

Around here the gas company and the electric company are the same animal so you can tell 'em its their problem.

On the electrolysis thing, every metal pipe water service I've ever seen is grounded to the metal water pipe deliberately on the utility side of the water meter. Out here in the hinterlands we use electrodes cause the water pipe is all plastic.

Admit I'm confused between the portions of the code that seem to say you can't ground/bond to metal piping systems and assertions that you must use metal water piping if present, e.g.:

250.52(B) Not Permitted for Use as Grounding Electrodes.
The following systems and materials shall not be used as grounding electrodes:
(1) Metal underground piping systems
(2) Aluminum

and kwired:

Water companies can complain all they want about current on the lines - it will happen anyway which is one reason why NEC wants metal water piping to be used as grounding electrode if it is present. Water piping will usually have lower resistance than any made electrodes - that is just the way they naturally are.

now the second contention doesn't have citation, but it jibes with every urban installation I've ever seen.

I also see that it is ambiguous whether what 250.52(B) is saying is that you have to install a separate electrode or you cannot bond to metal underground piping systems.

I think this worthy of fleshing out some more.

thanks,

brian
Click to expand...

I think I agree with most of what you said and/or you have agreed with something I previously said.

You are missing something in your quote of 250.52(B).

(B) Not Permitted for Use as Grounding Electrodes. The following systems and materials shall not be used as grounding electrodes:

(1)
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Metal underground gas piping systems

(2)
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Aluminum
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You ever seen what happens to underground aluminum conductors that have damaged insulation? If you have you will understand why they don't want aluminum used for grounding electrodes. It turns into aluminum oxide which is nothing at all like aluminum - and it does so rather quickly, unlike iron that will get surface rust rather quick but then will take longer to rust through the thickness of the object.
 
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