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Earth ground question!

Discussion in 'Pro Audio Equipment' started by Strat, Nov 26, 2004.

  1. Strat

    Strat Guest

    Hi there,

    I have found last night that my AC Panel (feeder) is not connected to an earth ground rod, outside of my home, it is only connect to the Water Pipe. Is this a problem security wise? I have been leaving here for the past 14 years and I never had a problem with this. I think the reason they never install a earth rod is because the bed rock is at 2 feet under the dirt and I believe that a earth rod has to go 8 feets down.


    I would like to do this my self so if you know a site that explain this please let me know! I am looking for what type of rod I should use.
    Thanks!
     
  2. sdevino

    sdevino Active Member

    The Water Pipe may be a lot better than the rod driven into the ground. If the water is metal and in contact with the earth for a sufficient length it will do very well as a solid earth ground.

    Its all a function of how much surface is in contact with the Earth and the gauge of the wire tied to it.
     
  3. Strat

    Strat Guest

    Hi sdevino,

    The water pipe is copper. Do you suggest a rod driven into the ground or having the ground only connect to the water system is enough?

    Thank you for your answer.

    Strat
     
  4. ghellquist

    ghellquist Member

    Strat,
    I would suggest that you call the electrical company. They are bound to have experts on this kind of thing. Often enough, if you ask realy nicely, they can give realworld experience and help.

    Gunnar.
     
  5. Davedog

    Davedog Distinguished Member

    A system grounded to the water pipe is preferable to a ground rod which,in the NEC,is considered to be a supplimentary ground source and is only required when water pipe or building steel is unavailable.And yes, I am an expert.
     
  6. Strat

    Strat Guest

    Hi Davedog and ghellquist,

    Many thanks for the clarification!

    Regards,

    Strat!
     
  7. Big_D

    Big_D Well-Known Member

    Cool info Dave, I am wondering is this because a 3/4" pipe filled with water offers less resistance than a steel rod or is it the fact that it is in constant contact with earth after exiting the building or both or neither? Sorry for the run on sentence.
     
  8. Davedog

    Davedog Distinguished Member

    It is because in an older system there is more direct earth contact with the supply for the water.With newer construction, its pretty much plastic all the way from the meter to the house and in a lot of cases its the same in a commercial install too.In these cases, we install, at the slab pour, what is known as a U-fer ground which consists of 3/4" rebar at least 20 feet in uninterupted length into the slab or the retaining walls.This is stubbed out under the electrical service area and all of your building bonds and grounds are brought to this location through one method or another.This is ,perhaps, the best ground of all other than a plate or ring tied to a balancing transformer.
     
  9. fbars

    fbars Guest

    Just a tip, I would recommend always checking with the local power company for THEIR code requirements for grounding.

    Here in Illinois, Ameren CIPS, the utility ABSOLUTELY requires a 10 foot ground rod of a certain size, located exactly 3 feet from from the building, with the proper size bare copper wire IN conduit.

    GROUNDING TO A WATER PIPE WILL FAIL THEIR INSPECTION!

    This is the code requirements for almost a 150 mile radius here.

    Tom Durso
    First Bass Audio
    Macomb, Illinois
     
  10. Davedog

    Davedog Distinguished Member

    Running a ground wire in a conduit without bonding it to one end creates a 'choke'...a situation which under a fault will more than likely burn your building to the ground.My information is based on the National Electrical Code which is not adopted everywhere...many local municipalities enforce the code in their own way with their own set of rules.HOWEVER....not bonding the water pipes in a building brings about the likelyhood of a potential between a steel sink and an appliance for example.The subject of this possible potential would definately be risking their life by being a part of such a thing.This would be a bit more than the 4 miliamps required to stop your heart.This is not to say its unwise to check with your local authorities on the subject.You can usually get a set of local rules at your building codes or inspection departments.And FBARS, I've been a Journeyman Electrician for 30 years and I would bet my teeth that you bond all your metal parts related to the plumbing to the system ground.
     
  11. Big_D

    Big_D Well-Known Member

    Dave, thanks for the clarification. When it comes to the juice, I listen to the pros.
     
  12. fbars

    fbars Guest

    Davedog,

    I have no doubt in what you say! Fourteen years ago I bought a home that I needed to rewire. It had the "knob and tube" style wiring, 60 amp service/meter, and the ground WAS to the water pipe. I went to the utility company for their requirements so I would be at their "code" to pass inspection. I too, was surprised that the ground was not connected to the water pipe. Their reason was because most homes in the region are plumbed with plastic PVC pipe, copper is not required.

    In December of 2003, I had to work directly with the engineer here, to install a new 200 amp service to my new studio building. I was given the requirements once again [on paper with drawings] as to what I had to do. I have a 200 amp commercial service and rate charge. My 200 amp meter/panel wire goes approx 25 feet underground to the transformer installed on my property by the utility, which they "tapped" directly to the primary. [Sorry if "tapped" is not the correct term.]

    I will try to find out more on this subject from the individual who actually installed the transformer. I've gotten to know him well, he's been with the company for 25 years, and might be able to shed more light on this.

    I get back to you ASAP,
    Tom Durso
    First Bass Audio
     

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