240v consumer unit earthing

[Stuupid]

Hi all,
I've earthed my consumer to the earthing point under my passenger seat. Someone told me I shouldn't earth the 240v to the van as if there was a fault it would fry my 12v system in the van. Instead I should rely on the red and the earthing back yo the who in the campsite.
Good idea or dangerous, what do you think?

 

[Dellmassive]

@travelvolts

whats your take on this. . . . . ?



The Victron guide covers a lot of scenarios . . .




it shows that a double pole RCD/MCB must be used . .

but also a possible issue if the campsite/shore power supply cores are reversed.

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https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

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7.5 Mobile installations

A mobile installation is an installation that operates independently from the grid. When it connects to AC power it usually connects to the grid at different locations and/or generators. For example, like boats, vehicles or mobile back-up power systems. In this chapter a boat installation is used, however, this information can be used for any mobile installation. A mobile system does not have an earth stake. So, something else in its place is needed to create a central earth potential. All touchable metal parts of the boat or vehicle must be connected to each other to create a local earth. Examples of metal parts in a boat or vehicle are: chassis, hull, metal fluid pipes, railing, engine, power point earth contacts, lightning conductors and the earth plate (if present). A mobile system typically connects to a variety of power sources it is sometimes not clear which of the leads in the shore power supply is connected to earth or if earth is connected at all. Also phase and neutral may have not been wired correctly. Connecting a supply like this to a mobile system can potentially create a short circuit to earth. Or earth is missing completely. It also matters if the mobile system connects to power or if it is disconnected from power and running autonomously.

 

[Stuupid]

All my kit has come from @travelvolts, would like to know whats the best/safest way of doing this.

 

[Dellmassive]

I've got my inverter earth connected to chassis for 240v ac. So effectively the 0v body ground is also acting as the earth geound.

But I haven't got any EHU in the van as yet.

So I suppose we looking for clarification if the earth bonding is continuous.

You can see the issue above with the diagram earth/neutral link.... if the body is earth and also neutral and 0vr ground the RCD might not trip as it needs to see an inballence of power in/out.

 

[Deaks]

This is a good question, and one I was going to ask too!
For 240v the earth is provided by the earth conductor in the hook up point, which all being well actually goes to a 'proper' stake in the ground earth at the site.
If this earth is lost, then the rcbo in the consumer unit should trip as expected.

But when the 240v earth is also earthed to the van, my gut feeling is that this is bad as the van is not really earthed to the ground like a earth stake is, mainly due to the four big black round things that are made of rubber.

I have bought a Renogy 2Kw invertor, and this has a little earth connection (in addition to the earth pin on the 240v input, as it can switch between EHU and 12v source), do I need to connect this, and if so, is it to the van body earth, or the earth as provided by the site hookup?

I wouldd really appriciate a defacto answer on these points, as I really dont like the feeling of 240v AC flowing through my body!!!

TIA

Deaks

 

[Stuupid]

Hi Dell and Deaks,
I've just checked the instructions from @travelvolts and it does say to earth the consumer unit to the earth point under the seat. I guess that's correct but I could also see an issue if there was a fault. At the moments mine is set up to run a battery charger and a couple of sockets.

 

[Dellmassive]

@Pauly any input from a Sparks?

 

[Dellmassive]

I'm thinking the issue may be the earth/nutral bonding inside the van.....

Say from inside an inverter or other bit of kit.

If the neutral was isolated from body ground . . . . . .

 

[Mud Digger]

i would say Run your 240 v supply and 240v earth Totally independently... your van is sat up on rubber Tyres and is not ground out what so ever ... this could make the whole van 240 v in a fault to earth ... remember like a break in the neutral wire, you would have 240 v right up to the break point. even through a tiny light bulb its full on 240v at that break point. Put RCDs on in your 240v distribution unit

The Victron unit might be double insulated on the 240v side not requiring an earth and cant touch the housing even in a fault condition

but lets the earth ground to chassis allowing the 12 v side to make its path back to the battery as normal or it would not flow as open circuit

the 12 v totally on its own is on the battery circuit that's all ....... its not an earth its making a circuit back to the battery

 

[Skyliner33]

Hi Dell and Deaks,
I've just checked the instructions from @travelvolts and it does say to earth the consumer unit to the earth point under the seat. I guess that's correct but I could also see an issue if there was a fault. At the moments mine is set up to run a battery charger and a couple of sockets.

I have a consumer unit and hook up kit bought from @travelvolts and the CU is connected to the vehicle 'earth' point under the seat. I just followed the instructions but thinking about it now it isnt really an earth point as there is no real path to earth. Therefore it is a bit concerning.

 

[Skyliner33]

i would say Run your 240 v supply and 240v earth Totally independently... your van is sat up on rubber Tyres and is not ground out what so ever ... this could make the whole van 240 v in a fault to earth ... remember like a break in the neutral wire, you would have 240 v right up to the break point. even through a tiny light bulb its full on 240v at that break point. Put RCDs on in your 240v distribution unit

The Victron unit might be double insulated on the 240v side not requiring an earth and cant touch the housing even in a fault condition

but lets the earth ground to chassis allowing the 12 v side to make its path back to the battery as normal or it would not flow as open circuit

the 12 v totally on its own is on the battery circuit that's all ....... its not an earth its making a circuit back to the battery

SO are you saying remove the CU earth to van connection?

 

[Mud Digger]

i would untill we get proper confirmation on what 240 supplys you are hooking onto the Chassis ground point


its is not a 240 v mains earth point that i am 100% sure of and its not touching earth till you touch your van

 

[The Bear78]

SO are you saying remove the CU earth to van connection?

What happens then if a fault in the 240 system shorts to the van body? Does it just wait for an unsuspecting victim?
My (often inadequate) understanding is that the van is earthed to essentially catch any stray electricity in the even of a fault and provide the easiest and safest route back to the ground.
Its easy to create scenarios in which almost any circuit will have the potential to cause harm. Perhaps we should all take a long copper rod camping!

 

[Deaks]

Hmmm, I'm still not sure about this. I did earth to the chassis when I installed the EHU consumer unit under the bonnet at the weekend.
I've not used it yet, but would like to be sure it's 100% as it should be.
Not looking forward to getting inside there again as it was super fiddly getting 3 x rcbos in the wylex enclosure!!

Deaks

 

[Mud Digger]

i will look into this you have got me thinking now i ll see what the Regs say

But if you hook a wire from Chasis to the earth in your consumer unit then it could be covered when you plug in to the 240 EHU

it might be practical to carry a plug in socket tester to check the 240 supply from the EHU that you have a earth in the camp site connection they are not a lot of money

 

[Stuupid]

Hmmm, I'm still not sure about this. I did earth to the chassis when I installed the EHU consumer unit under the bonnet at the weekend.
I've not used it yet, but would like to be sure it's 100% as it should be.
Not looking forward to getting inside there again as it was super fiddly getting 3 x rcbos in the wylex enclosure!!

Deaks

That's why mine is under the passenger seat

 

[Phil_G]

What happens then if a fault in the 240 system shorts to the van body?

i would say Run your 240 v supply and 240v earth Totally independently... your van is sat up on rubber Tyres and is not ground out what so ever ... this could make the whole van 240 v in a fault to earth ...

That would need two simultaneous faults, a live to chassis fault within some onboard equipment, and also the earth connection missing from the EHU source. With the source earth the Van and/or site RCD would definitely trip, and knowing how sensitive RCDs are I expect the capacitive mass of the van would trip it anyway even without a path to earth. IMHO of course. Mine & Roos both have the van chassis earthed as per the regs.
Cheers
Phil

 

[Skyliner33]

What happens then if a fault in the 240 system shorts to the van body? Does it just wait for an unsuspecting victim?
My (often inadequate) understanding is that the van is earthed to essentially catch any stray electricity in the even of a fault and provide the easiest and safest route back to the ground.
Its easy to create scenarios in which almost any circuit will have the potential to cause harm. Perhaps we should all take a long copper rod camping!

I've been thinking from the other way round. But if the van is connected via hook up to the earth then, yes I think that the CU should be earthed to the chassis/van.

As for the other, having an inverter and using 230V without an 'proper' earth would concern me much more.

 

[Deaks]

I just found this on the interweb......

To comply with BS7671 sect 721 any PERMANENT 240 volt installation in a vehicle (including caravans and motorhomes etc) should have the incoming mains supply earth bonded to the vehicle chassis. It also worth noting that any metal gas pipes should also be earth bonded.

Seems like my gut feeling is incorrect (wouldn't be the first time either!!).

Deaks

 

[Mud Digger]

What happens then if a fault in the 240 system shorts to the van body? Does it just wait for an unsuspecting victim?
My (often inadequate) understanding is that the van is earthed to essentially catch any stray electricity in the even of a fault and provide the easiest and safest route back to the ground.
Its easy to create scenarios in which almost any circuit will have the potential to cause harm. Perhaps we should all take a long copper rod camping!

i would say your house is not your van is not .... your sat in your van 240 live or hit by lightning its the your fine sat in the Faraday cage thing till you step out

theres no ground to earth or short cut from your van its sitting on rubber less you dangle a little anti static chain for car sickness behind you..

the Van is grounded to its battery only its not earth ( we call it earth ) its a circuit there's no other influences, even grounded is the wrong name