Grounding ? for PTO generator

I'm concerned about operating the generator before the connection is made to a grounded electrical system. If there were some wiring fault, frayed wire, or bad connection within the generator, it seems to me the frame (and the tractor) could become energized with some possible voltage difference to earth, and present a safety hazard.

Should the ground lug be connected to a ground stake, or similar earth connection to make sure the iron in the generator and the tractor remains at ground potential?

(a) Portable Generators. Under the following conditions, the frame of the portable generator shall not be required to be grounded and shall be permitted to serve as the grounding electrode for a system supplied by the generator: That means you don’t have to tie it to mother earth, the frame serves as a grounding electrode. (my own comments)

(1) The generator supplies only equipment mounted on the generator and/or cord and plug connected equipment through receptacles mounted on the generator, and
(2) The noncurrent carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame.

It looks like if you’re simply running cord connected loads off that portable generator, it needs no grounding (I’m talking about to a grounding electrode here). It does if the generator serves as a Separately Derived System and its Neutral were not tied to any building Neutral. In that case, its treated same as if from REMC’s transformer and needs to be grounded to a grounding electrode.

Nowwwww www, the generator and its Neutral, unless you provide it, has no reference to mother earth. It dont know what earth is and cares less. Any of its voltages are across and relative ONLY to its windings, NOT mother earth. Therefore, “theoretically”, if you stood barefoot on the wet ground and touched one of the hot bare generator terminals you should not receive a shock cuz theres no potential voltage difference between that terminal and mother earth. NOTE I DONT RECOMMEND THAT AND DO NOT TRY THAT AT HOME, there may be a connection to earth if its Neutral is connected to a buildings neutral DONT TRY THAT UNDER ANY CIRCUMSTANCES

Its if n when you tie into a building and then whether or not your generators neutral is tied to the buildings neutral (how many pole transfer switch you use) that determines whether or not it constitutes a Separately Derived System (requires a grounding electrode connection) or not. So long as its Neutral ties to the buildings Neutral there’s already an established grounding electrode, but if not (transfer switch) then you need to supply one to your system.

Clear as mud?? John T, Electrical Engineer retired

Think of it as a battery like powers your tractor. Let's just suppose that instead of 12vdc, the battery was sitting there at 120/240 ac. I know it's not possible, but follow me.

The way you act towards your battery is the same way you would act with your gen (except for the potential being larger).

All the power the battery is delivering (can deliver) is with respect to the tractor frame because that is where you tied your reference (the other terminal of the battery). You can put one hand on the tractor chassis and the other on the earth (ground) and nothing will happed because there is no complete circuit...you only have one line connected....the one your body is making.

To have current flow, hence produce a shock hazard to you, YOU (I mean your body) have to complete some kind of a circuit. Electrons have to leave the gen, go through something, enter your body, leave your body, and go through something else to get back to the source, the neutral (ground; return) on the gen.

So if the gen is isolated sitting there on ruber tires, there is no complete circuit to the earth till you make one. If you grab the power terminal or the ground terminal, with only one hand, and nothing else, you aren't going to get shocked. Period.

Now when you connect your gen to something; say a building, then you need a common point of reference. Since the gen has a gnd, neut, rtn terminal, that is your point of reference.

If you are powering a building for instance, your gen ref terminal must be connected to that building's reference with as big a wire as you are using from the power terminal and preferably as short as possible.....like park the trailer as close to the building's power box as possible. I'd tie to the power box ground, not the wire going to the rod in the earth (ground).

Then, with your generator reference now at earth ground potential, if you stand on the earth (ground) barefooted and grab the 120/ 240 gen output terminal you are dead meat....because the building is grounded (via the grounding rod connected to the power box reference), and you now have completed the circuit and can receive a lethal shock....gen output terminal to your hand, your feet to the ground rod thru the power return back to the ref on the gen....complete circuit...shock hazard.

If what I said is not absolutely clear, ask more questions.

Just be sure your building isn't connected to the utility companies power lines when you do this.

Mark