grounding

biff · April 17, 2012, 06:18:53 PM

Hi all.I have read here that you should not ground the bus chassis to shore line.Id like to know the reasoning behind this? Thanks.

Oonrahnjay · April 17, 2012, 06:33:04 PM

It's even more complicated than that, Biff. There is a difference in the ground system for shore power, inverters, generators, and other forms of power - they're different and they need to be switched. If it goes wrong, you can get a potentially fatal shock from power feeding through ground and/or neutral. Do a search for "transfer switch" and you'll find everything that you need to know.

Sam 4106 · April 17, 2012, 07:11:51 PM

Hi biff & Bruce,

Somewhere you have both been given incorrect information. The shore line GROUND (green) must be attached to the bus chassis. It is the NEUTRAL (white) that must NOT be attached to the bus chassis. Hopefully Sean Welsh will explain this to you much better than I can.

Good luck, Sam MC8

Oonrahnjay · April 17, 2012, 07:20:18 PM

Quote from: Sam 4106 on April 17, 2012, 07:11:51 PMHi biff & Bruce,
Somewhere you have both been given incorrect information. The shore line GROUND (green) must be attached to the bus chassis. It is the NEUTRAL (white) that must NOT be attached to the bus chassis. Hopefully Sean Welsh will explain this to you much better than I can.
Good luck, Sam MC8

Yeah, I was afraid that I was being "too simple". But I was thinking that he *really* needed to go read and understand the different discussions here to get the whole story. Everything he needs to know has been discussed and described here before.

buswarrior · April 17, 2012, 07:32:29 PM

Hi biff.

If you wire the coach wrong, there is a chance for someone to get electrocuted.

In reading all this confusing stuff, do not forget that.

The concepts can be quite confusing, leading to the many discussions, debates and arguments found on the Boards and in the Archives.

There are simple ways to do it, there are complicated ways to do it.

The threads will have the words "neutral-ground bonding" used in them.

To make it more dangerous, many, many electricians have no idea about this topic.

Read carefully, lives you care about depend on it.

happy coaching!
buswarrior

Gerry4104 · April 18, 2012, 12:47:07 PM

could anyone that has done this just explain this direction wise, in laymans terms for us ? thanks guys... Gerry

bobofthenorth · April 18, 2012, 01:41:32 PM

Its been explained at least 100X in the archives but here's the Coles notes:
Black = 110 hot
White = 110 neutral
Green = 110 ground
Red = 12 V +
Yellow = 12 V -

Black, white, green go directly from the fixture/outlet back to the panel.
White & green are on SEPARATE buss bars in the panel (ie: NOT conncted)
Red from 12V load centre to 12V loads
Yellow from 12V loads to bus frame is most common practice. The circuit is completed by strapping battery neg to the bus frame
Green is bonded to bus frame only at the panel

If you add in a genset or inverter none of the above changes but the genset/inverter will add one connection not present in the above scenario. However if you wire as above then adding an inverter or genset is a stand alone issue.

Oonrahnjay · April 18, 2012, 01:48:18 PM

Quote from: Gerry4104 on April 18, 2012, 12:47:07 PMcould anyone that has done this just explain this direction wise, in laymans terms for us ? thanks guys... Gerry

bevans6 · April 18, 2012, 02:37:41 PM

I simplify this down considerable - and may get called on it...

Ground is bonded everywhere. ("bond" just means connected). The chassis is bonded to the ground wiring bus, and the cable out to the power pedestal includes ground. You do connect the pedestal ground to the bus chassis. You can have multiple ground connections at different places.

Neutral is different. You pull all the neutrals on the bus back to a single point and bond them all together. You then, with switches or cables, connect neutral to the source of power - if that is pedestal, external generator, internal generator or inverter - and the source of power then connects neutral to ground. No other connection besides that single neutral to ground connection should exist. Some generators "float" neutral and ground - they do not provide the single connection. I favor adding that connection inside the connector or cable, but that is also a point of discussion.

I also favor, it you think there is a need, a ground stake and tie between the bus chassis and the actual ground (the stuff you walk on). I have had 40 - 50 volt ground loops where the chassis had potential to the ground despite the cable to the pedestal.

Brian

Oonrahnjay · April 18, 2012, 02:41:56 PM

Quote from: bevans6 on April 18, 2012, 02:37:41 PM(snip) I also favor, it you think there is a need, a ground stake and tie between the bus chassis and the actual ground (the stuff you walk on). (snip)

Electrics isn't one of the things that I'm really up on but I agree with you on this. I have one with my bus.

chev49 · April 20, 2012, 08:24:17 AM

it also doesnt hurt to check voltage from chassis to the actual ground when you plug in... a 1 min job.

biff · April 20, 2012, 06:57:05 PM

Thanks guys for the responce.