THE INFORMATION BELOW ABOUT GROUNDING THE AC IS WRONG! YOU DO GROUND THE AC TO THE BUS. NEUTRAL SHOULD NOT BE BONDED TO THE GROUND, BUT THE AC SHOULD BE GROUNDED TO THE CHASSIS. Edit added after I went back and read the instruction manual again....
Originally Posted by Bullwinkle
I believe that you do want your AC box grounded to the bus body. If it were not, and the hot lead were to make contact with the body, your whole bus would have a 110 volt potential to ground – which would be a nasty surprise to anyone walking up and laying a hand on it….
What you don’t want is for the neutral (white) wire to be grounded to the body. A lot of the breaker boxes that you might buy in a Home Depot-type store will have a bolt you can install to short the neutral to the box (ground). If this were done on a box installed in a bus, some of the current that would normally flow through the neutral might decide to shortcut through someone touching the bus. Not as nasty as scenario #1, but it could still be hair-raising.
Negative, negative. Do NOT ground the AC to the bus body. RV's should have a "floating" ground. That is, the ground should ONLY connect to the ground through the ground on the shore power cord to the campgrounds ground at the campground's distribution box. You are absolutely correct that you do not want a hot or neutral wire to short out to the body. If you ground the bus body, there is a greater likelihood of YOU being the ground to the bus if you touch a hot wire. If you have no ground to the body, and touch a hot wire and the bus, there will be a less effective path for the electricity to follow.
First, there are two kinds of breaker boxes, "mains breaker" and "mains lug". The difference is that in one there is a big breaker on the incoming hot supply line(s), while with the other, the incoming hot supply lines are just screwed down with a lug (bolt), and there is no breaker between the bus and the "mains" (service line).
Inside the breaker box (distribution panel) there should be two bars with a bunch of screws in them. One is for ground, and one is for neutral. All the ground wires (including the incoming service ground) get hooked to the ground bar. All the neutral wires (including the incoming service line neutral) get hooked to the neutral bar. All of the hot wires get hooked to breakers (including the incoming service line hot wires).
Some breaker boxes give you an option to connect the ground terminals directly to the neutral terminals via an optional connecting do-hickey that swivels over from the ground to the neutral side. DON'T. The ground and neutral on the bus should remain completely separate. Be sure not to bolt the service box to any metal on the bus -- don't bolt it to a wood panel and run the bolts into the bus, either, as that's the same as bolting to the bus. Absolute separation.
Extremely good information on this topic in http://www.phrannie.org/battery.html
. Phred recommends the following book:
"Another must-have book is "RV Electrical Systems" by Bill and Jan Moeller. With both AC and DC electrical systems and excellent 12 volt coverage, it is the best source I've seen on 120 volt AC systems. If it's not covered in this book, you can probably get along without it. The authors go into extraordinary detail without getting into engineering "lingo" and tell you things nobody else does (and those things many authors assume we already know--that we don't). With this book you won't be the dumbutt at a rally who miswires something and screws everybody else up. $19.95, 265 pages, detailed illustrations. In many bookstores, RV stores and from Amazon."
I got the book. WELL WORTH THE PRICE. Extremely valuable information. Saved me more than the price by just preventing me from making ignorant screw-ups.