[Milsurplus] Electrical question...

[J. Forster]

Ryan Gill wrote:

> At 1:24 PM -0400 6/23/06, J. Forster wrote:
>
> >Completing the 'path' or more properly the circuit is the function of the
> >neutral wire. The ground is to protect the operator in case there is a short or
> >path in the load or generator from the hot side to the metallic case. The ground
> >prevents YOU from becoming part of the circuit (and making you dead).
>
> If the generator doesn't have a low impedance path to ground, you touching a hot lead shouldn't create any more of a path should it? I'm thinking strictly mobile systems here.

It only takes a few milliamps to kill. Current can flow through stray capacitances as well as resistors.

> In theory, unless the generator is someone connected to earth, there's not a good path between a hot item, your hand, you, the ground and then back to the generator's electrical system (the neutral that's bonded to the chassis of the generator...).

It's YOUR life. I'd make sure the protective ground is intact and grounded and the neutral connected to the protective ground.

> Some loads off the portable system will have a ground wire from the equipment back to the generator, others will not have a ground at all (simple lighting).

It's called double isolated. Some portable tools are that way. The theory is two failures are much less probable than one, so you need a two point failure to kill you.

> How does this differ from a system that's entirely portable like that of a motorhome or RV? The generator get's bonded to the motorhome, but not all the way to the ground. So why don't you get a zap when you step on board?

If you are inside, the AC neutral and ground should be tied to the chassis. If you are outside, the tires likely insulate and are low capacitance to ground. I'd ground mine, if  had one.-John