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I'm helping my brother convert his van into a camper and installing solar panels, a leasure battery, and hook-up point, but I'm slightly confused. I've been working on the hook-up and loads of things have been said to connect Earth from the hook-up to the chassis of the van.

I'm rather worried about this because the vehicle is modern enough to have all the DC systems for the vehicle use the chassis as a negative return path to the battery.

Surely if I connect AC earth and something goes wrong and the AC system tries to ground I would be sending AC live/natural into the negative of the battery setup so I could be feeding a current into the negative of a battery. Would this not fry the DC electronics?

Just on this note: the hook-up point is not being connected to the DC system anywhere; it's completely isolated from the DC system. There are just going to be four AC power outlets that can be used should the hook-up point be connected.

Also, I'm in the UK; this is 240 V and 16 A potential, so should a live or natural wire somehow get shorted to the chassis that is 3840 W drawn quite easily, enough to kill someone touching the outside of the van and the actual ground/earth should a trip fail.

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    \$\begingroup\$ Please show a diagram how you intend to hook it, and how exactly it would be possible for positive current end up in battery negative (and from where)? \$\endgroup\$
    – Justme
    Commented Aug 7, 2022 at 20:42
  • \$\begingroup\$ I don't have a diagram to hand, but the Hook up point is an a 981201 leed into a socket in the van side wall, then from that it goes into a "consumer unit", the consumer unit has an earth rail, a neutral rail and then the Live via trip switches, according to the documentation that came with the Consumer unit I should be connected the earth of that to the van chassis, and because AC switches I could be sending a current though it when it earth and then I have 2 currents hitting each side of a battery... \$\endgroup\$
    – Martin Barker
    Commented Aug 7, 2022 at 20:51
  • \$\begingroup\$ That last paragraph is why the vehicle chassis needs to be solidly grounded. \$\endgroup\$
    – Simon B
    Commented Aug 7, 2022 at 21:08
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    \$\begingroup\$ The last paragraph is also an example of why a qualified professional installer should be used. \$\endgroup\$
    – Nedd
    Commented Aug 7, 2022 at 21:28
  • \$\begingroup\$ That's not advice how is anyone supposed to learn if they have someone else do it for them, the whole setup is going to be sent to an electrical to go over and certify it, but not install it all because electricians in the UK are a ludicrous price at the moment they are still playing catch up from C19. \$\endgroup\$
    – Martin Barker
    Commented Aug 7, 2022 at 21:58

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Connecting the vehicle chassis (battery negative) to AC Earth (ground) is OK.

With no faults, the + of the battery will only be connected to the existing sockets/loads, and will not interact with the AC power.

If an AC fault occurs and shorts live to neutral -- the AC fuse (or circuit breaker) will blow.

If live shorts to ground, this will not interact with the battery DC supply (you are only connected to one terminal -- no current can flow in that path); the fuse will blow.

If Live can physically short to battery +, then you would have an unsafe system -- it needs to be physically arranged (double insulation; don't have wires close etc.) so that a short to ground would have to occur before a live to + could occur.

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  • \$\begingroup\$ Yeah the Cable is well insulated, 15mm cable thickness with 3 cores at 2.5mm copper and wrapped in 2mm insulation so has about 5 mill of insulation before it can contact the van and even then I'm running it though loom casing where ever it going near metal of the van \$\endgroup\$
    – Martin Barker
    Commented Aug 7, 2022 at 22:09

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