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grounding of gas manifold

zepfan
zepfan Member Posts: 333
i have a customer that is selling their house, and they had a home inspection done where the inspector had recommended that the gas service manifold in the basement be grounded. this is a 2 psi system where the manifold is in the basement located in the same room as the furnace, and water heater.the electric service comes in to the house in the garage, no where near the gas manifold. Wouldn't it be sufficient to put a grounding clamp on the gas manifold, run a ground wire across the ceiling of the furnace room, and put a grounding clamp on the cold water line (copper) and ground it that way? to get to the main service ground, i would have to run a wire half way around the house. thanks to all.

Comments

  • JStar
    JStar Member Posts: 2,752
    edited November 2014
    Can you install a grounding rod outside near the meter?
  • kcopp
    kcopp Member Posts: 3,997
    Is this a CSST installation?
  • Jamie Hall
    Jamie Hall Member Posts: 19,155
    Your idea of grounding to the water pipe sounds, initially, as though it makes sense -- but it will not meet any electrical code. Grounds must run, independently, to the grounding bus of the main switchboard which, in turn, must have an independent exterior ground.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Bob Bona_4Zman
  • BobC
    BobC Member Posts: 5,312
    I just had the service to my house replaced, new feed and panel. They installed two ground rods that connect to the panel (which is grounded to both sides of the water meter) through an exterior buss bar.

    I was told anything that has to be grounded should attach to this exterior buss bar. Different jurisdictions may have different rules and regs.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • SWEI
    SWEI Member Posts: 7,356
    To clarify a bit: Gas piping (CSST or otherwise) must be bonded to the service entrance ground. Additional ground rods are great, but the key is to minimize any potential difference between the metallic piping and any other systems in the building.
    Gordy
  • BobC
    BobC Member Posts: 5,312
    I was trying to convey that all grounding should be done back to the house ground. Adding a separate ground rod that is not bonded to the electric service ground would not be safe because a potential could develop between the two in the event of a lightning strike.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    Bob Bona_4
  • Jamie Hall
    Jamie Hall Member Posts: 19,155
    SWEI said:

    To clarify a bit: Gas piping (CSST or otherwise) must be bonded to the service entrance ground. Additional ground rods are great, but the key is to minimize any potential difference between the metallic piping and any other systems in the building.

    My point exactly.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 6,893
    Grounding at the manifold is a terrible idea as it could actually induce a lightning strike to travel to that point. Bonding (the correct term) should be done as close as possible to the point of entry into the house between the gas line and the grounded service conductor buss, the GEC or the grounding electrode (rod).
    The idea is to take a strike off the gas line before it gets into the house, not give it a path to travel all the way to the manifold.

    A lot of home "inspectors" have just enough knowledge to be dangerous.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • BobC
    BobC Member Posts: 5,312
    In my mind the question is with gas services now being run with plastic pipe and many houses using CSST, what are we trying to bond. If a plastic pipe supplies the meter should the bonding be to the meter and the valve?

    Hopefully Tim will see this and respond.
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • zepfan
    zepfan Member Posts: 333
    no this is not a csst installation.steel pipe from the meter in to the 2 psi regulator ,from there copper is run to all of the appliances. the more i think about it probably would be best to install a ground rod near the gas meter outside, and run a ground wire from it to the piping attached to the meter.
  • SWEI
    SWEI Member Posts: 7,356
    If the gas pipe enters the building more than about 10 feet laterally from the existing grounding electrode(s), there will be little to no benefit from driving a new rod. OTOH, if the distance is more than that (especially with newer coated iron pipes), an additional rod will benefit both the electrical system and the gas piping.

    Bonding to the EGC should be done at or near the boiler whenever there is non-conductive pipe or fittings between the gas pipe entry and the boiler supply piping. If the non-conductive pipe runs to or within a couple of feet of the boiler, the EGC for the boiler's AC supply will suffice. There are subtleties (mostly for commercial and industrial installations) related to available fault currents in nearby conductors as well.

    Stainless chimney liners or other metallic flue pipe should also be bonded -- especially if it leads to the roof. In lightning-prone areas, I would also drive a new ground rod at or near the bottom of any vertical flue run.
  • Tim McElwain
    Tim McElwain Member Posts: 4,517
    Bonding and grounding is becoming a nightmare with CSST, plastic gas services etc. I have been advising people to get the mechanical inspector and the electrical inspector together and get a definite answer to what locally needs to be done. It varies so much in each area that it is difficult to just look at National Codes and know what to do.

    By the way my experience with lightning has been that no matter what you do if you get a direct hit nothing works. Grounding and bonding are only good for indirect hits. I have seen black pipe with holes blown through it, copper for AC on rooftops blown apart all of those were grounded and bonded and it did not make any difference.

    Grounding is really more inclined to be for electrical safety to prevent people from getting electrocuted.
    Bob Bona_4
  • kcopp
    kcopp Member Posts: 3,997
    So what part of the code is this home inspector "quoting" that the gas service needs to be grounded.
    I thought that gas was grounded through the appliance.
  • Gordy
    Gordy Member Posts: 9,514
    edited November 2014
    This was sort of a topic at Mike Holts web site the wall of electrical as I see it.

    this is only part of an answer to the discussion, but it covers gas piping from the electrical side of the trades.

    "As far as the gas line is concerned, if it's a "hard pipe" system, 250.104(B) comes into play and in most cases an equipment branch circuit takes care of the bonding for you. If it happens to be CSST flexible gas piping the mechanical Codes come into play and they most often want the gas manifold bonded to the service grounding electrode system."

    So you are bonding to grounding for the service panel., and sub panels do not count.
  • icesailor
    icesailor Member Posts: 7,265
    Tim says it best.

    If you get a direct strike by lightning, all bets are off. Unless you have a professionally installed lightning suppression system installed by those that know what they are doing and how to do it.

    I lived in a high lightning area. I built a house in a valley. Once I moved in, I had two direct hits in 6 weeks that did severe damage. It could have been worse but I had a 2" galvanized shallow well pipe that I had direct grounded from the panel. Plus the cold water pipes. The things that happened are written in horror movies. I had a suppression system installed immediately. That was in 1986. I had noticed that there were many tops of pine trees that were broken off. And it wasn't wind. After it was done, I was never hit again. I moved in the Fall of 1999. Before that, houses all around me were hit numerous times. Holes in well casings are common letting sand in. Satellite antennas on the ground were common. Many of the strikes were "Back Strikes", strikes that happen AFTER the down strike.

    It's my opinion that much of the damage done to houses is during the back or after strike. If you get hit by a main strike, you're dead. If you get hit by a back strike, you hurt, maybe dead. I hurt when I was hit under a house, by a strike near by (within a mile) and it came back through a well pipe, under a house, when I was trying to put a jet pump back on.

    They want residential fire sprinklers in rural areas when the pumps won't work without power? And they don't require lightening suppression systems in high lightning areas? Those golfers that stand under trees during lightning storms? They get hit. They get blown out of their shoes. The bottom of their feet are burned and the grass is burned under the shoes. Their head isn't blown off. Its those metal spikes in the shoes. The lightning came out of the ground as the back strike or ground to cloud lightning.

    Don't mess with lightning.