bonding propane line
- Thread starter kitsr
- Start date
- Status
pierre
Senior Member
- Location
- Westchester County, New York
Re: bonding propane line
250.52(B)(1)
Electrodes not permitted:
(1) Metal Underground gas piping system
250.52(B)(1)
Electrodes not permitted:
(1) Metal Underground gas piping system
pierre
Senior Member
- Location
- Westchester County, New York
Re: bonding propane line
250.104(B) Other Metal Piping.
..."Including gas piping, that is likely to become energized shall be bonded to the service, ... The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. "
250.104(B) Other Metal Piping.
..."Including gas piping, that is likely to become energized shall be bonded to the service, ... The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. "
charlie
Senior Member
- Location
- Indianapolis
Re: bonding propane line
Kitsr didn't mention anything about a grounding electrode. However, it would be the same as a gas line and only be bonded by the circuit that would be likely to energize the line like Pierre's second post states.
Kitsr didn't mention anything about a grounding electrode. However, it would be the same as a gas line and only be bonded by the circuit that would be likely to energize the line like Pierre's second post states.
charlie
Senior Member
- Location
- Indianapolis
Re: bonding propane line
Yep, but it is already bonded to the generator by virtue of the fact that it is attached to the generator. Another bonding jumper is not required.
Yep, but it is already bonded to the generator by virtue of the fact that it is attached to the generator. Another bonding jumper is not required.
Re: bonding propane line
Another problem with propane is that in order to shut down a leak you also have to crack a fitting downstream of the shutoff valve and blled off excess pressure. I have yet to see a propane installation that has a shutoff valve tha tautomatically vent off pressure to a little more than atmospheric pressure. What would concern me when bleeding off the pressure is if the line is not grounded against static electricity or if there is an electrical device nearby. Propane is also heavier than air and takes a long time to diffuse away, particularly if just boiled off from the liquid state.
Also, almost every natural gas pressure regulator that I have seen on a single occupancy building does not have a shutoff valve on the low pressure side of the regulator, so you would have the same problem.
Another problem with propane is that in order to shut down a leak you also have to crack a fitting downstream of the shutoff valve and blled off excess pressure. I have yet to see a propane installation that has a shutoff valve tha tautomatically vent off pressure to a little more than atmospheric pressure. What would concern me when bleeding off the pressure is if the line is not grounded against static electricity or if there is an electrical device nearby. Propane is also heavier than air and takes a long time to diffuse away, particularly if just boiled off from the liquid state.
Also, almost every natural gas pressure regulator that I have seen on a single occupancy building does not have a shutoff valve on the low pressure side of the regulator, so you would have the same problem.
paul
Senior Member
- Location
- Snohomish, WA
Re: bonding propane line
This is a moot point, as the line is not likely to become energized in this situation.
This is a moot point, as the line is not likely to become energized in this situation.
charlie
Senior Member
- Location
- Indianapolis
Re: bonding propane line
Frank, for something to become energized, doesn't it have to have the ability to come into contact with something else that is energized? If the line is isolated by means of an insulating hose, how is it likely to become energized?
Frank, for something to become energized, doesn't it have to have the ability to come into contact with something else that is energized? If the line is isolated by means of an insulating hose, how is it likely to become energized?
paul
Senior Member
- Location
- Snohomish, WA
Re: bonding propane line
Even if it were tied into the engine via a metallic connection, the genset would be the source of voltage that would energize the line, not the main service from the POCO. Therefore, the genset, including the engine that the fuel line is tied to, would have to become energized. The OCPD [for the generator] would have tripped by this time...hopefully. If not, then prepare yourself for one helluva light show.
The propane line in this case is not likely to become energized.
[ May 13, 2005, 05:29 PM: Message edited by: paul ]
Even if it were tied into the engine via a metallic connection, the genset would be the source of voltage that would energize the line, not the main service from the POCO. Therefore, the genset, including the engine that the fuel line is tied to, would have to become energized. The OCPD [for the generator] would have tripped by this time...hopefully. If not, then prepare yourself for one helluva light show.
The propane line in this case is not likely to become energized.
[ May 13, 2005, 05:29 PM: Message edited by: paul ]
Re: bonding propane line
Charlie,
Who knows how something might become energized,it could be done on purpose. If something is isolated from the bonding system,it will be the only thing that is likely to become energized. The water pipe certianly is not likely to become energized,right?It's bonded to the service enclosure any circuit that may contact the water pipe will trip real fast.
250.104(B) FPN states that bonding metal ducts will provide additional safety, Why? because the ducts are isolated via flexible transition right near the unit,what circuit would likely energize these ducts? If the eletrical installation was installed right, then what is there to become energized. Do you see where I'm coming from here, How can it be stated that the EGC can be used for something that might become energized,if it can then there is no EGC. I don't know
frank
Charlie,
Who knows how something might become energized,it could be done on purpose. If something is isolated from the bonding system,it will be the only thing that is likely to become energized. The water pipe certianly is not likely to become energized,right?It's bonded to the service enclosure any circuit that may contact the water pipe will trip real fast.
250.104(B) FPN states that bonding metal ducts will provide additional safety, Why? because the ducts are isolated via flexible transition right near the unit,what circuit would likely energize these ducts? If the eletrical installation was installed right, then what is there to become energized. Do you see where I'm coming from here, How can it be stated that the EGC can be used for something that might become energized,if it can then there is no EGC. I don't know
frank
Re: bonding propane line
I have encountered an instance where the metal drain pipes in a house were partially energized by a leaking underground electrical line near the other end of the house. The line to the detached garage was leaking 7 amps at 120 volts during a drought. The line was only about 20 maybe 30 feet long. Since the electricity had to flow to the water service lateral at the front of the house they did not need to install an electric driveway deicing system.
What I had to do to get the nasty tingle voltage out of the bathtub was to bond the cast iron drain pipe to the grounding electrode conductor. What I had to do to get the tingle voltage out of the washing machine was to cut the power to the detached garage. Since the bathtub and the washing machine were near the water service I figured that the drain pipes and basement floor had 40 to 50 volts on them.
What was really weird was that the kitchen sink should have had 70 to 80 volts across it. Evidentally, the kitchen sink was doing some ad hoc bonding.
And yes, the water supply pipes and the washing machine were properly grounded.
I would not want ANY electrical equipment near a propane tank. What do you think would happen when the relief valve pops on a hot day?
[ May 14, 2005, 01:10 AM: Message edited by: mc5w ]
I have encountered an instance where the metal drain pipes in a house were partially energized by a leaking underground electrical line near the other end of the house. The line to the detached garage was leaking 7 amps at 120 volts during a drought. The line was only about 20 maybe 30 feet long. Since the electricity had to flow to the water service lateral at the front of the house they did not need to install an electric driveway deicing system.
What I had to do to get the nasty tingle voltage out of the bathtub was to bond the cast iron drain pipe to the grounding electrode conductor. What I had to do to get the tingle voltage out of the washing machine was to cut the power to the detached garage. Since the bathtub and the washing machine were near the water service I figured that the drain pipes and basement floor had 40 to 50 volts on them.
What was really weird was that the kitchen sink should have had 70 to 80 volts across it. Evidentally, the kitchen sink was doing some ad hoc bonding.
And yes, the water supply pipes and the washing machine were properly grounded.
I would not want ANY electrical equipment near a propane tank. What do you think would happen when the relief valve pops on a hot day?
[ May 14, 2005, 01:10 AM: Message edited by: mc5w ]
paul
Senior Member
- Location
- Snohomish, WA
Re: bonding propane line
mc5w,
I had a trouble call some years ago where a little guy, about 4 yrs old, got zapped while brushing his teeth. I got there and sure enough I was getting voltage on the sink. The faucet was fine, as it measured zero volts to the nearest rcpt. ground. The drain, however was hotter than a pistol. So I climbed down underneath this house, post and beam mind you with all the mildew a Pacific Northwest home has to offer. I found nothing out of the ordinary and was kinda stumped. Old house, cast iron drains. Hmmm...must also have a cast iron vent pipe. I start quizzing the homeowner of anything that they may have done to the house in the recent past. Turns out they had blown in insulation installed just a few days prior. I climb up in the attic and sure enough, there's a K&T wire running about 8 inches from the cast iron drain tube sitting in the still wet blown in insulation.
I do the best I can of clearing the insulation from the wire and the vent pipe. I then go back under the house and add a #4 bare bond to all of the drains. I also warned the homeowner that K&T is not meant to be insulated around and explain the hazzards.
mc5w,
I had a trouble call some years ago where a little guy, about 4 yrs old, got zapped while brushing his teeth. I got there and sure enough I was getting voltage on the sink. The faucet was fine, as it measured zero volts to the nearest rcpt. ground. The drain, however was hotter than a pistol. So I climbed down underneath this house, post and beam mind you with all the mildew a Pacific Northwest home has to offer. I found nothing out of the ordinary and was kinda stumped. Old house, cast iron drains. Hmmm...must also have a cast iron vent pipe. I start quizzing the homeowner of anything that they may have done to the house in the recent past. Turns out they had blown in insulation installed just a few days prior. I climb up in the attic and sure enough, there's a K&T wire running about 8 inches from the cast iron drain tube sitting in the still wet blown in insulation.
I do the best I can of clearing the insulation from the wire and the vent pipe. I then go back under the house and add a #4 bare bond to all of the drains. I also warned the homeowner that K&T is not meant to be insulated around and explain the hazzards.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: bonding propane line
Paul, thanks for sharing that.
I wonder, given the static charge issue, wouldn't it be better to avoid bonding the gas pipe under any circumstance? That way, there would be no (theoretical) source of ground for a spark?
Paul, thanks for sharing that.
I wonder, given the static charge issue, wouldn't it be better to avoid bonding the gas pipe under any circumstance? That way, there would be no (theoretical) source of ground for a spark?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: bonding propane line
I had a similarly-bizarre chain of events cause the EGC of an entire circuit to become energized a couple of years ago. It took me about 20 minutes to discover the cause, which was probably as old as the house.
The then-undersized grounding conductors in a two-gang switch box had not been capped; typical practice back then. The EGC of the incoming home-run happened to be nicked when it was stripped, and broke sometime later.
The twisted bare wires happened to be pointed upward, and the broken EGC slowly screwed itself down the spiral like a nut on a bolt, probably from household vibrations, until it came into contact witha hot screw on one of the switches.
This was discovered the usual hard way: by shocks received when using the bathroom light switch, as the fingers swept over the plate-screw heads. The metal box energized the switch straps, which in turn energized the screws.
Fortunately, there was enough slack in the cable to expose just enough of the broken EGC to extend it with a small wire-nut, and reconnect it to the original joint, which I, of course, remade with a second wire-nut.
The homeowner declined my suggestion doing this repair to the rest of the house. "I'll call you back if it happens again." I'll be here.
I had a similarly-bizarre chain of events cause the EGC of an entire circuit to become energized a couple of years ago. It took me about 20 minutes to discover the cause, which was probably as old as the house.
The then-undersized grounding conductors in a two-gang switch box had not been capped; typical practice back then. The EGC of the incoming home-run happened to be nicked when it was stripped, and broke sometime later.
The twisted bare wires happened to be pointed upward, and the broken EGC slowly screwed itself down the spiral like a nut on a bolt, probably from household vibrations, until it came into contact witha hot screw on one of the switches.
This was discovered the usual hard way: by shocks received when using the bathroom light switch, as the fingers swept over the plate-screw heads. The metal box energized the switch straps, which in turn energized the screws.
Fortunately, there was enough slack in the cable to expose just enough of the broken EGC to extend it with a small wire-nut, and reconnect it to the original joint, which I, of course, remade with a second wire-nut.
The homeowner declined my suggestion doing this repair to the rest of the house. "I'll call you back if it happens again." I'll be here.
- Status