What gets grounded, what doesn't?

[hyperlogos]

I know my DC power well but I am not so familiar with AC. I did read the noshockzone stuff but it doesn't seem to come out and say what I want to hear. It says make sure to test and so on but doesn't explain this: What is actually supposed to be chassis grounded? From what I can tell it's the DC ground bar, and the converter chassis. Am I also supposed to ground the distribution center chassis, or not? I know I'm not supposed to tie the neutral bar to ground. I'm currently dealing with a Parallax Power 80D, it has an isolated neutral bar, and an AC ground bar connected to the distribution center chassis.

[roach711]

If your bus has a steel body (not fiberglass like a shuttle bus) the AC breaker panel needs to be grounded to the body in order for the breakers to work if an AC hot wire touches the body. You no doubt read about the "hot body" condition on NoShockZone.

What confuses many is that "ground" is a different concept in AC and DC circuits. In a vehicle DC circuit the ground wire (or the body) simply completes the circuit similar to the neutral in an AC circuit. It will carry current whenever the circuit is powered on.

An AC ground normally doesn't carry current unless there is a shorted hot lead. Without a ground wire between the AC breaker panel and the body skin a shorted hot wire won't trip the breaker and touching the body could shock someone who's touching the metal body while grounded.

Your AC panel should have separate ground and neutral bus bars. Neutral and ground should only be bonded (connected) at the shore power panel.

[hyperlogos]

Originally Posted by roach711

If your bus has a steel body (not fiberglass like a shuttle bus) the AC breaker panel needs to be grounded to the body in order for the breakers to work if an AC hot wire touches the body. You no doubt read about the "hot body" condition on NoShockZone.

Yes, and elsewhere.

Your AC panel should have separate ground and neutral bus bars. Neutral and ground should only be bonded (connected) at the shore power panel.

So to be totally clear, I need a ground wire from the distribution panel chassis to the vehicle/trailer chassis so the breakers will trip if something shorts to the chassis, and one from the battery as normal as well to complete the circuit for the DC equipment, is this correct?

[roach711]

Correct! The AC and DC grounds work fine when connected to the same body/chassis.

When I first started down the bus conversion path the one thing that was hardest to wrap my brain around was getting the two electrical systems to play together.

[hyperlogos]

Originally Posted by roach711

Correct! The AC and DC grounds work fine when connected to the same body/chassis.
When I first started down the bus conversion path the one thing that was hardest to wrap my brain around was getting the two electrical systems to play together.

I've read like ten different articles on hot skin and whatnot and while all of them said what not to do, none of them spelled out what I actually need to do in a clear and straightforward manner, so this was super helpful. Thanks.