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[Tim McCulloch]

Bill Whitlock and others had a panel at AES and that addressed grounding.  Bill directly questioned why someone would insist on an earth ground.  It might be worth getting a copy of the panel discussion to review.
Bill is very generous with his knowledge and made his presentation available for the asking after the convention.
I do remember him asking where the earth ground is on a 747.

Try "grounding" a ship, electrically speaking... grounding them on the beach or rocks is much easier.

[Charlie Zureki]

Why exactly is that? There is no safety added by a ground rod except for lightning protection. The "earth" is not a great big sink into which all electricity returns.

Mac

  +1
 
   And...the NEC was in deliberations about the merits of grounding/not grounding portable generators for some years.  I haven't check the latest NEC updated Code book, but, wouldn't be surprised if there isn't a new Code that would apply.

  Hammer

[Don Lind]

So whats the decision?

Should I continue (in California) being a PITA and insist on an earth ground or just let it go...

[Charlie Zureki]

So whats the decision?

Should I continue (in California) being a PITA and insist on an earth ground or just let it go...

   Hmm... the decision is not ours to make.  Check the NEC Article 250
  and OSHA (29CFR 1926.404 (f) (3) (i) )

   Hammer

[Tim McCulloch]

So whats the decision?

Should I continue (in California) being a PITA and insist on an earth ground or just let it go...

If you are using only the outlets on the generator set, powering only 1 item from each outlet, then NEC does not require a grounding electrode.

If you are hooking up a distro, then it is considered a "point of service" and must have a grounding electrode for the generator, and the generator neutral must be bonded to that ground.

Your local jurisdiction may have differing requirements as the NEC is a 'model' document that can be adopted wholely, in part, or modified by your city, county or state.

edit p.s.  Hammer beat me to the citation...

[Charlie Zureki]

If you are using only the outlets on the generator set, powering only 1 item from each outlet, then NEC does not require a grounding electrode.

If you are hooking up a distro, then it is considered a "point of service" and must have a grounding electrode for the generator, and the generator neutral must be bonded to that ground.

Your local jurisdiction may have differing requirements as the NEC is a 'model' document that can be adopted wholely, in part, or modified by your city, county or state.

edit p.s.  Hammer beat me to the citation...

       +1 ...as Mr. McCulloch wrote...and, providing NEC or local Codes does not conflict with the OSHA code.

   Hammer

[paul bell]

Don, I would say that grounding a generator set with a rod, while it really does nothing electrically, will do no harm. Many inspectors expect to see a generator grounded so if you do it, it won't draw their attention.

However, if your local code requires it, do so. This is not the right place to get definitive code compliance answers. Check with your local buildings department electrical inspections division.

[Charlie Zureki]

Don, I would say that grounding a generator set with a rod, while it really does nothing electrically, will do no harm.

   Hmm... not necessarily, please read the NEC and OSHA codes on this subject.

  Hammer

[Jeff Bankston]

Jeff,
Unfortunately you are incorrect.  The earth ground only exists as a protection against lightning strikes. 
Yes, the neutral and safety/fault ground (U ground on a standard parallel blade, u ground receptacle) lugs within a service entrance panel are required to be bonded and, therefore, the safety/fault ground links to neutral as a secondary return path to the neutral and therefore to the AC generating source.  At service entrance the safety/fault ground bus is tied to an earth ground rod (or other code acceptable ground) for protection against lightning strikes.  In this case it is possible, if the impedance is low enough, for someone to touch a hot leg and touch something earthed and be electrocuted.  The only reason this is possible is the bonding of the neutral to safety ground (required or it wouldn't be a safety ground) and the tying of safety ground to earth at service entrance.  Only in this way is the earth a part of the return path for the potential.  Otherwise, the earth is not, and cannot be, a part of the circuit.

Lee

theres more to it than what you posted. for example you have a 480/277 volt panel in a building. you need some 120/208 power. you install a 480 to 120/208 transformer. you do not use the neutral off the 480 service so therefore you must get a new neutral by grounding the xo on the transformer. the transformer is considered a new service. you must run a ground wire from the xo on the trans to the cold water pipe. you must also run an additional ground wire to a ground rod or building steel. the xo lug is where you run a white color coded wire from xo on the trans to the neutral buss of the 120/208 panel. if you do not ground the xo you will have 120v on the neutral and fry whatever is plugged into a receptical. the cold water ground is the primary grounding system. the ground rod is the backup just in case something happens to that water pipe or building steel connection. the earth is the ground in this case. if you want to know more Mike Holt has some good learning material. theres just a lot more then there is room and time to type here. i didnt learn this stuff overnight either.

[Tim McCulloch]

i really didnt want to post on this thread anymore BUT theres more to it than what you posted. for example you have a 480/277 volt panel in a building. you need some 120/208 power. you install a 480 to 120/208 transformer. you do not use the neutral off the 480 service so therefore you must get a new neutral by grounding the xo on the transformer. the transformer is considered a new service. you must run a ground wire to the cold water pipe and ground the xo. you must also run an additional ground wire to a ground rod or building steel. the xo lug is where you run a white color coded wire from xo on the trans to the neutral buss of the 120/208 panel. if you do not ground the xo you will have 120v on the neutral and fry whatever is plugged into a receptical. the cold water ground is the primary grounding system. the ground rod is the backup just in case something happens to that water pipe.

I'm trying to remember all the exceptions and conditions, but IIRC a water supply pipe is no longer generally considered suitable for use as a primary grounding electrode.  I'll have to look that up at work tomorrow.

You are correct about "separately derived services" requiring bonding of the grounding electrode and "grounded current-carrying conductor" at the point of service.

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