While we were touring Spain this winter we pulled into a site and pitched up as usual. I connected the electricity while Virginia put the kettle on. We then called our collie Rue into the van and as he put his foot on the metal step he flew backwards at a vast rate of knots. We couldn't understand what had happened , and when we tried to get him in again he would not come near the van. We tried the polarity tester and that showed normal. I touched the step myself and could feel nothing until I put one hand on the ground and one on the step and received a nasty shock!! Somehow the van was live. We tried another plug in point and all was well so we reported it to reception who couldn't apologise enough. This made me think about earthing the van. We have rubber tyres and usually wooden or plastic feet under the legs and I wondered if anyone else has had this problem and if an electrician thinks all vans should be earthed or is there someway of testing without getting a shock!!

It took Rue about a week before he stood on the step again, entering and leaving the van with a big leap over the step. Thankfully no harm done.
DSC_0309.jpg - Bild entfernt (keine Rechte)

One tip from my army days may prove useful. Our trucks were always connected to a mains generator with earthing spikes. When touching the truck it was always with the back of the hand first. the theory being you would be thrown off (like your dog), rather than having a death grab on the door handle due to your muscles contracting. Still something I always test when hooking up.

Surely you circuit breaker in the van should have kicked in to prevent that.
Dave

I theory the polarity should have nothing to do with it, if earth leakage occurs it should trip out, that's the whole point of a circuit breaker.
Dave

I think for the RCD to trip, the circuit would need a path to earth. If a caravan is standing totally on insulating materials e.g rubber tyres and plastic feet on the corner steadies this is quite likely.

But if it's working correctly it should trip before you feel a shock, and when the dog was thrown back it should certainly have tripped, not stayed set.
Dave

If the only earth connection is through the hook-up then then the RCD tripping would be dependant on the integrity of the site earthing system, a good reason for using a test plug, particularly outside the UK.

Eric

No, the dog became the earth so
the vans RCD should have tripped.
Dave

True - the only way you feel something is when a circuit is made which is why when you touched the step whilst in the van first time you did not feel anything. The RCD should trip as soon as the dog touched the step and made a circuit.

RCDs should be checked every months in domestic installations ,they can fail

Remember though that if your RCD doesn't trip when you test it, that indicates a fault. You shouldn't normally get any current going down the earth in any case. Maybe in this case the site power live or neutral was shorting to earth. My RCD is rated at 300mA which would certainly be felt before it tripped.
It is probably a good idea not to test for electrical problems with your body though. Asking for trouble.

FWIW 300mA is way more than it takes to kill you!!!!!!


Steve.

300mA is way too high a rating to provide adequate protection. The maximum rating should be 50mA to provide shock protection, commonly used in domestic installations..
Caravans should be fitted with 30mA due to their “uncertain” earthing.
Our 2016 Triton has a 30mA rcd fitted, as supplied by Hymer.
I suggest you get your installation inspected by a qualified electrician.
Jef

Surely poster meant 30mA?

Stewart