ECN Forum Forums Code Related Discussion NEC & other Code issues Gas pipe bonding

Here in NJ the gas company has been installing new pipe that looks a lot like a little plastic garden hose. The bore a hole under the street and toward the house, then they pull this little hose through the tunnel. There is no digging required. Unless they hit rocks.

Should we meg it to see how much of a bond there is?

Should I use this equation?

1000V arc + Natural Gas + O2 = KaBoom!



[This message has been edited by sparky66wv (edited 09-19-2002).]

Before breaking a connection on exterior metallic gas piping the workman should install a "working ground" on both sides of the break. Isn't this required in their safety rules? I know if I were working on this stuff I would assume if I seperated a connection I would get a spark and I would plan accordingly. I mean how the hell would I know what's going on with the pipes inside the house? Maybe some DIY used the gas pipe for a hot lead to melt the snow in his driveway.
Bob

if memory serves, there's a fairly narrow ignition window re; gas/air ratio.....

part of the article in question.....

HB commentary......



so...is the confusion the EGC's possible inability to 'bond' an interior mettalic gas pipe which, thru the gas unit's structure isolated from said EGC ???

Sparky,
No confusion, the EGC would be sufficient for Code and for real. My concern as an inspector would be any pressure reducers which may not allow the EGC to be continuous for the piping, but other than that it would be fine.

The problem is that 7 years ago, one county was requiring that the gas pipe be ISOLATED from the electrical service, including removing the EGC for the branch, AND that is apparently happening again with another county. You may be assured that if I get my hands on a rejection slip for this behavior, war will be declared.

30 year ago, we were required to treat the gas pipe as an electrode. This was often accomplished by bonding across the hot and cold water pipes + the gas pipe at the water heater. In that way the bond is pretty much assured. There would be nothing illegal about this method today, it would assure continuity, and bond it downstream from the utility, thereby meeting all codes, and allowing me to sleep better about the pressure reducers.

I've had problems with pressure regulators in water pipes, bad ones, so I tend not to trust these devices.

Ahhhh for the good ole days, back when Men were Men, and Hamburger didn't need a helper.

Sparky,

You talk about Kaboom, my ex brother in law use to work for the gas company. Sometimes they would have to get down in deep trenchs to repair gas pipe. They had to "WELD" it back together again. Well, every now and then there would be some left over gas in the pipe and KABOOM, it would shoot out of there like a flame thrower.

Not sure of the exact percentage, but methane gas is explosive only in the range of abiout 4 to 15%.

Bet those welders learned not to stand in front of the pipe.

Tom

Went on a service call to check cook getting zapped from all gas pizza oven.Cook went to hospital.
Checked voltage,450V to ground. Service to building 120/208V 3phz.
Followed gas line to roof,across roof and down to meter.Meter in the backyard of family dwelling.
Found roof flashing in contact with gas line also energized.Looked arround roof a found sign hanging from roof flashing with farmer wire.Circuit to the sign 120 2 wire with nm flex no ground.HO ballast bad.
Moral to this story;Granted the sign was not grounded but if the gas line would have been bonded,the pizza dude would have been calling me to repair the sign.