Common earth for 12v and 240v?

Just doing all my leisure wiring and I am just wondering if by using the common earth (the van shell) for all 3 systems - bolting the negative earth for the two 12v systems to the van shell and the earth for the 240v consumer unit as well, could there be a conflict, it may trip the consumer unit if all are running at the same time?
The 3 being the
1) 240v set up
2) 12v leisure
3) 12v main battery
Can anyone help?

 

Both batteries will use the van body as a common return (the -ve connection). Earth the consumer unit to the van body as well. The mains earth isn't the common return - the mains neutral performs that function. You still need to ensure that all metal expanses in the van (including for example any metal sink) is earthed via the hookup. This'll ensure the breakers trip if any area of metal becomes live.

 

WHS
RCD measure the current differential between the 2 230v conductors using a current transformer and a current transformer doesn't work with DC so no risk of tripping the RCD with a 12vdc backfeed

 

Thanks everyone - will do the sink as well - just like at home.

 

Nuff said!!!

 

Yes, no issues, I have the 230 V Earth taken down to the earth stud onto the body, should also bond the gas pipe if you have one...

 

Yep. Anything metal that could become live by something dodgy (eg duff kettle) touching it needs earthing, just like at home.

The incoming hookup earth (hopefully it's connected to something at the other end) needs to go to the van body as well.

 

17th edition electric regs (the latest) do not require bonding of all metals (sink, radiators etc)
I would just earth the body

 

Does that apply to pipework as well kilmo

 

17th edition only requires gas and water to be bonded where they enter the property

 

Its a case of being sensible, I bonded the gas pipe because the instructions with my Sargent hook up panel said to do it, not really sure if it is or is not needed. The reason that the regs now say not to bond everything is the incident when an MP's daughter or relative died and they think it was because a metal sink was incorrectly bonded which meant she got a lethal shock. They reckon that the installation was such that if the sink hadn't been bonded she would have not got a shock, don't know the full story...

 

17th reg under the special locations (Campers) only require you earth the body
the sink should not be in a position to become live and if it does you would still need to contact a ground in this case the body work that is protected

The house gas and water only need boding if the pipes entering the house are metal and the house has a RCD if no RCD bonding of all accessible metal is required