Gas pipe

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The code states you must bond the gas pipe to the service. It also states that you may NOT use the same gas pipe as a grounding electrode. When you bond the gas pipe are you not essentially making it a grounding electrode? How is current from a lightning strike going to know the difference between a bonding conductor and a grounding electrode conductor?

[ June 24, 2004, 12:18 PM: Message edited by: iaspiretowire ]
 
Re: Gas pipe

In my opinion, its all about what is connected to the line side of the service equipment and what is connected to the load side of the service equipment.

During a lightning event or high-voltage crossover, the GEC become the path of the surge currents. In this case, we do not want the gas pipe apart of this system.

On the other hand, a gas pipe that may become energized needs to be bonded so in the event of accidental contact with an energized source, an effective ground-fault path is crteated an OCD's will operate.

Lightning will likely not seek this path as it is not a direct connect to Earth and is on the load side of the service equipment, and the use of a dielectric fitting at the gas meter should isolate the internal bonded pipe from the outside pipe.
 
Re: Gas pipe

The code states you must bond the gas pipe to the service.
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Sorry, the Code does not say that. What the Code does say is, "(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible."
 
Re: Gas pipe

Sorry Charlie, what I gave was the condensed version. Sorry I didnt reprint article 250 for my question. The bottom line is I have a gas pipe that may become energized so the code states as I said you MUST bond the gas pipe. Can you answer my question or are you only able to quote articles from the NEC???? :roll:

[ June 24, 2004, 01:33 PM: Message edited by: iaspiretowire ]
 
Re: Gas pipe

does that mean that it would likely be energized by a branch circuit in a residence and therfore would size your bond to the largest branch gec?
I usually jumper at the water heater to the hot cold and gas with a #6 on 100-200 amp service.
Eric
 
Re: Gas pipe

I intepret 250.104(B) to mean that using the EGC in the circuit feeding a gas-fired appliance is effective way bond the gas line.
...Using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means.
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"May energize" is the key term as I read it: A dedicated circuit feeding an attic receptacle is not likely to energize a gas line, and therefore has no bearing on the sizing of the gas-pipe bonding conductor. But the circuit connected to a gas-fired boiler definitely does have the potential to energize the gas line. In which case, the EGC for boiler circuit is a suitable bonding means.

-John
 
Re: Gas pipe

I think Bryan answered the question. The dielectric (insulator) that the gas company installs at the gas meter prevents the gas line form being used as a grounding electrode.
Karl
 
Re: Gas pipe

Sorry to ruffle your feathers but I thought Bryan had given you a good answer. I was interested in making sure you understood that it was not required to run a conductor sized in accordance with 250.66 to the gas piping system (that is why I italicized some of the text). Actually no conductors need to be connected to the gas piping at all since the circuit that grounds the appliance will ground the gas pipe. :D
 
Re: Gas pipe

Personally I think using the appliance EGC is a poor method of bonding the gas piping. Here in Ca., we use a lot of flexible "appliance connectors" (metallic corrugated tubing) between the appliance gas shut-off valve and the appliance. These connectors are often epoxy coated and won't provide a suitable electrical connection. A hot/cold/gas piping bond at the water heater is often done.
 
Re: Gas pipe

Personally I think using the appliance EGC is a poor method of bonding the gas piping.These connectors are often epoxy coated and won't provide a suitable electrical connection.
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Stamcon, if there is not a suitable electrical connection then the gas pipe is not likely to become enrgized, unless of course you use poor wiring methods.
 
Re: Gas pipe

iaspiretowire :
"The code says you must bond the gas pipe to the service"
Are you referencing the 1999 NEC or 2002 NEC, there is a huge difference, 99 says you do, 02 removed, as the 99 didn't specify how to size the bonding jumper, from 250.66 or 250.122
 
Re: Gas pipe

I was talking about the 2002 code. The reason I posted the question is due to the fact that there is a 200A panel mounted almost directly above a gas main. I was worried there could be a difference of potential between the panel and the gas pipe and someone might get shocked. I bonded the gas pipe with a #6 (from table 250.122) wire to the service panel. Then I was worried that a lightning strike might send current down the bonding wire and possibly cause the gas pipe to explode. Maybe I worry too much :( So if the appliances that are using gas and elecricity are grounded through the circuit ground wire then maybe I dont need to have the #6 bonding conductor??

[ June 27, 2004, 04:17 PM: Message edited by: iaspiretowire ]
 
Re: Gas pipe

Sometimes our work is not cut and dry. Your example of the gas meter/main below the panel is a violation in itself. As for it being of a diferent potential is interesting.
Is there an electrical connection to the gas system (such as a range, oven, etc..)?
If not and there is no connection to the electrical system, I think you have good reason to worry about potential difference and bonding is a good idea. If it is connected to the electrical system via an equipment grounding conductor from a circuit, I would not be as concerned.
 
Re: Gas pipe

Originally posted by iaspiretowire:
Can you answer my question or are you only able to quote articles from the NEC???? :roll:
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Can you read the NEC and understand it, or are you only able to ask questions? :roll:

I am going with the latter.

Beleive me Charlie is qualified for the task. I can assure you that my life would be easier if my Resume had half of the things that Charlie's contained. Better still, don't take it from me, take it from the hundereds of employees he has trained at Indiana Power and Light. Or, perhaps you might ask the thousands of students that he has taught in his tenure as an instructor. Or, ask some of the people that have read some of his official interpratations to article 240, of which he is a principle code making panel member.

You know what, better still, lets just not insult people on this site when they are trying to help you out...especially when they are way out of your league. There are few people on this site who's opinion is nearly gospel....Charlie is one of those very few.
 
Re: Gas pipe

Originally posted by charlie:
The code states you must bond the gas pipe to the service.
Click to expand...
Sorry, the Code does not say that. What the Code does say is, "(B) Other Metal Piping. Where installed in or attached to a building or structure, metal piping system(s), including gas piping, that may become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122 using the rating of the circuit that may energize the piping system(s). The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible."
Click to expand...
Yeah, I read it Ryan. It leaves alot of room for interpretation. Thats why I asked my question on this site to try and get some real life situations from the "experts". Im here to learn. Im not here on some power trip and I sure as hell am not here to stroke some other guys ego. :roll:
 
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