Curious to know how many people are bonding the interior metal gas piping system in a residence (house side of the meter)to the electrical system ground. There have been some changes in the Code wording in the '02 Ed. but I am interested in who does or doesn't do in and why.
250.104(4)(B) requires it, as does our local utility. So, I do it.
State of Virginia abso-posilutely requires it.
It's required by our "code" in England as well.
We were told in a code change meeting earlier this year given by the Middle Department Inspection Agency in cooperation with Allegheny Power and the IAEI that the "intent" of the code was not to directly "bond" the gas pipe to the service equipment unless it was not bonded by a circuit supplying a gas fired appliance.
An example would be the 120 volt circuit that you would run for a gas furnace. The pipe would be bonded through the furnace.
But, if there was a gas appliance (or propane, etc.) that did not have a power connection, such as a gas fire place, then you must intentionally bond the pipe. And this is only if there were no other gas appliances in the building that were also supplied by an electrical circuit of any size.
Thats how it was explained to us in this area.
Can't wait to see the feed back on this one!
the utility I work for forbids it. It causes electrolysis on gas lines. Also all new gas lines going to the homes are plastic.
Dan,
Your utility forbids the bonding of the inerior metal gas piping system? This rule is directly from the Fuel Gas Code, NFPA 54. Both NFPA 54 and the NEC forbid the use of the ungerground gas pipe as a grounding electrode. Both require the bonding of the interior metal gas piping system.
The gas companies in this are always used a dielectric fitting at the gas meter when they were still using metal underground piping. Now they are using nonmetallic distribution piping.
Master66
Yes, it appears that the intent of the code is to permit the EGC for the gas appliance to be the interior gas piping bonding conductor and that no additional conductors or bonding is required.
Don
[This message has been edited by resqcapt19 (edited 07-15-2002).]
I checked our book again on requirements for electric service, it states the grounding electode conductor installation a.the gounding electode conductor connections must not be made to gas pipes, b. on indoor installations, the grounding electrode conductor can be copper or insulated aluminum. On outdoor installations the grounding electrode must be copper. Also there is not one ground wire attached to my gas pipe, or any other home that I have worked on.
Master66: I like your reply, seems to be what the 2002 Code aludes to. One issue to consider is on a gas appliance is the gas line SOLIDLY bonded to the equipment ground?? Have come across arcing between gas furnace enclosures and the gas line... NOT solidly bonded I would say! Although the line to the furnace had an equipment ground conductor connected to the proper terminal on the furnace. Also, the bond, wherever it is, has to reflect the LARGEST circuit feeding an appliance connected to the gas line.
danb1: I understand the requirement not to use the gas main as a grounding electrode. However, it seems inevitible that the interior piping will become connected to an equipment ground within the residence at some point, either intentionally or casually. I think the intent of the requirement here is to make sure that the connection is solid.
Effective June 22, 2001 the Indiana Electrical Code (IEC), which uses a modified version of the 1999 NEC effective February 12, 2001, deleted the last 7 words of 250-104(b).
I have no idea why.
IMHO, leave the NEC as written.
Glenn