A question for the electricians - earthing the 240v consumer unit

Right, so even though it is effectively the same earth inside a van they have to go to separate points? Just checking as I am in the middle of sorting my 240v system. Could it be on an earth right next to the 12 v earthing point?

 

I would use a finely stranded 6mm single core cable in green/yellow with a proper ring terminal and bolt it through the body with an 8mm brass bolt washer/washer nut, you can get these from any electrical wholesalers for pennies. The IIE regs say that any cables run together have to be insulated to that of the higher voltages so any 12V cable that run near the 230V should be sleeved in flexible conduit which is rated to withstand 230V or even better re routed away from the mains cable.
In practice it makes no difference if the 12V is earthed to the same point but its good practice to separate them.

 

Put them as far apart as you easily / reasonably can. It's the same electrically, but good practice to keep the two systems separate.

 

Cool good to know

 

Im not going to argue as if its easy to do then - do it but for info the bolt I have my earth connection to - also has a negative earth return on it. As the earth wire is actually a bonding connection that connects the body to the earth terminal and thus through the supply cable to the supply earth Ive yet to work out what type of fault would necessitate seperation of the two circuits as the whole of the chassis is negative and should the chassis become live then the fault current should pass to earth through the supply earth. Disconnect it and the fault path could feasibly be through you! ie stood next to the van - touch it and ouch!! But also this would result in any negative earth cabling becoming live - cant quite work oyt what the outcome of that might be! Brain not working just now. Sure there must be a paper on it somewhere.

 

you also need to put an " Do not remove" type Earth bonding tag on it

 

Dunno - would get the regs out but........

 

Regs are for wimps...

 

BS7671:2008 Section 721 covers caravans and motor caravans, with Annexe A to this section covering the DC battery side of things. All structural metal parts that are accessible from within the caravan / motor caravan need to be connected to the MET (721.411.3.1.2).

 

You'll find that BS2001 cleans a big, big carpet, for less than half a crown...

 

This is luxury you can afford by Cyril Lord....

 

Aah. Those were the days!

 

why can't you share the earth point, surly as soon as they are both earthed they are"shared" anyway, or am I missing something?

 

It will work but it's bad pratice and not strictly to the the regs

 

As above, there's no electrical reason why you can't, but if you were rewiring a building, good to keep mains and low voltage seperate.

 

Going to do mine this weekend sowill separate earthing points but how far apart do they need to be or is it they just have to be separate ? Planning to put 12v fuse box and CPU next to each other for neatness.

 

Did you get a solution to this?
I’m sorting my electrics out and was planning to put a couple of Consumer Units (one for hook up and another for an Inverter) in a cupboard already containing my 12v fuse and wiring...


In theory there is space and most of the wires are in conduits, as would any new ones.
Trying to separate gas from electrics as I read that is also a requirement.


Sent from my iPhone using Tapatalk

 

The point is that the earth wire should big enough and well enough grounded that it cannot blow up before the mains input fuse blows.
If you share an earth point and it becomes loose, you may be injecting mains into the negative supply side of 12 volt gear. More random bangs and smoke you didnt need to have.

Put them at least far enough apart that a loose mains earth cant slide over and touch the 12 volt earth

 

Thanks.
Think i’ve fried my brain, which is better than frying the Bay, as I was interpreting some of this thread to mean that ALL 12v & 240v wire had to be separated...which would render my electrical unit unusable because it has sockets for both.
Although i’ll still keep all wiring neatly separated in to circuits, it’s good to know to specifically be aware of the 240v earthing.
Cheers


Sent from my iPhone using Tapatalk

 

As long as the earthing points are well screwed down, there won't be a problem. Stick 'em on the same earthing point.