# electric shock from body of motorhome



## sunsaz1

Does anyone know why we have started getting electric shocks from the body of our hymer motorhome? We were travelling around France last summer and had no problems until we came back to the UK and plugged in here. We are living 'on-site' in her so it is a bit of a problem! All the electrics in her work fine.


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## JohnsCrossMotorHomes

sunsaz1 said:


> Does anyone know why we have started getting electric shocks from the body of our hymer motorhome? We were travelling around France last summer and had no problems until we came back to the UK and plugged in here. We are living 'on-site' in her so it is a bit of a problem! All the electrics in her work fine.


Check that the polarity of your hook up lead or mains supply socket is the correct way round.

Peter


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## rayc

sunsaz1 said:


> Does anyone know why we have started getting electric shocks from the body of our hymer motorhome? We were travelling around France last summer and had no problems until we came back to the UK and plugged in here. We are living 'on-site' in her so it is a bit of a problem! All the electrics in her work fine.


I presume these are tingles and not lots of sparks etc? Check that there is an earth bond between the incoming earth in the mains lead and the vehicle chassis. If I am wrong and you are getting a belt when you touch the body I suggest you jump out and call an electrician.


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## loddy

Do you have earth ?

Loddy


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## sallytrafic

Assuming this only happens on hookup I suspect (suspect only mind you) that the hymer is not wired to UK wiring regs and the chassis/metal skin is unearthed then the fault might be that there is a partial path to chassis for the live side of the supply (perhaps a frayed cable or badly wired circuit). Get it checked by a competent electrician ASAP


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## waggy3

hi there,
how bad are the shocks?
if just a sharp stab it could be static electricity caused by friction with some materials.
if you get another on strait away and are stil alive get it checked asap.
roy.


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## erneboy

It is important you know whether it is static, which I get all the time (depending on the clothes I am wearing), or mains. As already said if it happens twice in quick succession then it is most probably not static and could be very dangerous. If it is static some fabric conditioners are anti static and should stop your clothing building up a charge, Alan.


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## sunsaz1

*thanks*

To all who have replied, thank you. 
I have a bad feeling that it's not just static so we will get it checked asap.


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## pippin

You do have an RCD protected supply (from the EHU post), don't you?

You have pressed the TEST button to make sure it operates correctly, haven't you?

If NO to either/both those questions then WHY NOT?!!!!!

They are essential checks before you even start to connect your blue plug to the MH.

If the hook-up point (not the one on the MH) is protected by a properly-operating RCD then that should trip as you get your shock, preventing any further danger.

The question of reversed polarisation (NOT polarity, there is no DC involved) should not even come into the equation if the RCD at the post is working correctly.

If there is no RCD then WHY NOT??

Yes, polarisation is more important in that situation.

Our Hymer has just about everything metal bonded to just about everything else that is metal, making shocks within the van very unlikely.

I assume that you are getting shocks when you are outside the van standing on wet grass and then touch the bodywork?


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## pippin

I hope that the lack of response from sunsaz1 doesn't mean that.......


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## sunsaz1

For all those eagerly waiting to hear if I'm still alive........eeeeek BANG!
:lol: 
We are going to get a auto electrician to look at her. Thanks for all your help.
Just out of interest, would a bad connection of the earth to the body chassis cause this? There looks like there is a bit of corrosion. Hubby's fingers are getting tingly and he's fed up with wearing Marigolds as they only come in yellow or pink!!!


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## Jean-Luc

sunsaz1 said:


> For all those eagerly waiting to hear if I'm still alive........eeeeek BANG!
> :lol:
> We are going to get a auto electrician to look at her. Thanks for all your help.
> Just out of interest, would a bad connection of the earth to the body chassis cause this? There looks like there is a bit of corrosion. Hubby's fingers are getting tingly and he's fed up with wearing Marigolds as they only come in yellow or pink!!!


An auto electrician is the wrong kind for main/grid issues and would not be suitably qualified, you should contact an electrician qualified in main/grid electrics, like you would get if you had a problem in house electrics.


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## sallytrafic

sunsaz1 said:


> For all those eagerly waiting to hear if I'm still alive........eeeeek BANG!
> :lol:
> We are going to get a auto electrician to look at her. Thanks for all your help.
> Just out of interest, would a bad connection of the earth to the body chassis cause this? There looks like there is a bit of corrosion. Hubby's fingers are getting tingly and he's fed up with wearing Marigolds as they only come in yellow or pink!!!


You probably have a two fault situation possibly made worse by live and neutral being crossed over.

If it was properly earthed and fed from a serviceable and tested RCD then the RCD would trip with a live to Earth, or Neutral to earth, fault. (If the fault current was more than 30mA)

The on board RCD would only trip if the fault was downstream of the on board RCD trip.

So for example if, on a poorly or non-earthed van, the cable from the inlet connector on the side of the van was frayed and resting on the chassis (possibly in a damp bit) then that would raise the potential of the van to a point that might be dangerous however until it draws more than 30 milliamps then the supply RCD won't see that as a fault and won't trip but it may be enough to give you a shock and less than 30mA has been known to kill.


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## Glandwr

I get shocks (static ones) from most tyred vehicles, if I’m not wearing leather soles or bare feet. Heat seems to make it worse. Wife is quite amused by my sudden starts. But there again she always has been.

Try it bare foot.

Dick


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## sallytrafic

You trying to kill them Dick


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## Glandwr

You're right suggesting that I am not the most informed re MH electrics Frank, but the implication is that it has been happening for a while now. 

I do know however that I seem to “manufacture” static. I try to wear no artificial fibres or footwear. They seem to make it much worse. At times when I wear trainers/wellies etc. I get a static shock when “earthed” to a battery, as you are when touching a tyred vehicle. 

I have often wondered why this is. Does it happen to everyone but they can’t feel it or my energy levels high?   

Dick


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## pippin

Ditch the Lycra fetish - problem solved!

I don't know why some individuals feel static shocks more than others.

Perhaps it is another advantage of being "thick-skinned"!!


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## erneboy

That has always happened to me too Dick, others do not seem to experience it as often. In sunny weather it is especially bad. Maybe some of us just generate more static than others. Frank can you tell us why this happens please, Alan.


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## sallytrafic

I wonder if the mods should move these static posts 

Basically a static charge is obtained when two non conducting materials (one may be conducting) rub against one another so for example a helicopter flying through the sky, you combing your hair and wearing nylon all can cause a static charge to build up. If the air is damp then this charge leaks away. If you generate static and then touch something at earth potential a small spark will jump from your body and you get a nervous reaction. Although the everyday static can be many 100's of volts it doesn't produce enough current to kill. Except for the big ones like lightning, (produced by movement of ice particles through air) which may be millions of volts and very high currents. Even then though the frequency of the step waveform reaching you means than the current passes over the body rather than though it meaning that often people survive lightning strikes with only superficial burns.


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## raynipper

pippin said:


> Ditch the Lycra fetish - problem solved!
> I don't know why some individuals feel static shocks more than others.
> Perhaps it is another advantage of being "thick-skinned"!!


It's all down to our physical make up Pippin.
Some people including myself can hang onto a live wire and just feel a tingle when wearing normal shoes.
But others who have a more moist makeup would get a severe belt.

I had a similar fault on my van a couple of months ago and eventually found it was the 16a. blue 'caravan' plug that must have got wet inside and arked across between the live and earth.
Only found it because I could smell the burnt plastic when I rolled up the cable.

Ray.


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## safariboy

Rather than bare feet which will kill you if the problem is at all serious the best way of dealing with static is to touch a piece of wood. Or pick up a piece of wood and touch the van. It is a highish resistance and will discharge static.

Seriously the van sounds as if there is a serious wiring fault and too many people have been killed with this kind of problem. You need a caravan or motorhome workshop. Neither an auto nor house electrician can be guaranteed to have the right equipment and know how motorhomes are supposed to be wired. Without a proper check it is quite impossible to know what the problem is.


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## sunsaz1

Just to let you know, we have reversed the polarity on our hook up lead and that seems to have done the trick. No more shocks. 
Thanks to everyone who has contributed.


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## safariboy

Reversing polarity should not have this effect. The polarity issue is a safety one and if all the insulation is in good order it should not make a difference. If there was a line to body fault it is now a neutral to body fault. You may not get a shock but it is still a fault.
I am surprised that the ELT in the camp power supply did not trip. The fault is probably only allowing a small current.


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## sallytrafic

All you have done is partially hidden one of the faults. A neutral to earth fault will trip an RCD (except in circumstances where the supply companies neutral - earth connection is very near such as in a TNCS earthing system).

It is still an accident waiting to happen.


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## raynipper

Put it back and it could be a great deterrent for thieves.

Ray.


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## kenny

*DO YOU HAVE FUSSEY HAIR*

DO YOU HAVE A LAMP HOLDER THAT YOU COULD CONNECT 2WIRES FROM,IF SO DO THAT CUT THE INSULATION OF THE ENDS PUT A BULB IN PRESS ONE END ONTO YOUR VAN AND THE OTHER END TO A WATER PIPE OR THE METAL ON YOU STAND WHERE YOU PLUG IN ,IF THE BULB LIGHTS UNPLUG YOUR CABLE AND BE READY FOR A BIG BILL CALL A ELECTRICIAN FAST, NO ELECTRICITY IS BETTER THAN A WOODEN BOX.
KENNY ( RETIRED SPARKY)


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## sunsaz1

We are obviously not electricians and all this is a bit above our capabilities (as if you hadn't guessed).
We went to a local Motorhome service and accessory centre and they didn't know what to suggest and are too busy to look at her in the near future. 
Could it be that we have a live connection touching the bodywork of the van or could it be that the earth on the van has a bad connection?
Any suggestions are very welcome.


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## Jean-Luc

As the fault now seems to be mains power related an auto electrician will not be suitably qualified, you need a 'house' electrician to check over the mains circuits in your van asap to identify the source of the fault and fix it. Messing with mains power by unqualified persons is not recommended.


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## erneboy

You have had lots of good advice on here, please act on it before someone gets killed, Alan.


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## Fatalhud

sunsaz1 said:


> Any suggestions are very welcome.


Get a qualified Electrician to test your mains powered system as soon as possible :roll:

Alan H


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## steco1958

Fatalhud said:


> sunsaz1 said:
> 
> 
> 
> Any suggestions are very welcome.
> 
> 
> 
> Get a qualified Electrician to test your mains powered system as soon as possible :roll:
> 
> Alan H
Click to expand...

Could not agree more, GET AN ELECTRICIAN NOW !!!!!!!!!!!!!!!!!!

Sorry to shout but this is a dangerous situation.

Steve


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## kenny

*hi kenny*

the way you describe it it sounds dangerous i am going a bit tec now, if you van van is wired ok,make sure all you eqpt is un pluged lights turned off then try to do what i said if the bulb lights you have a big problem , this is what i would do un plug the cable with the test lamp touch any 2 terminals in your site plug you sould get a light across 2 terminals twice 1-2 1-3 if not your site is wired wrong if ok plug your cable back in. do the same at the other end if not the same,the cable is faulty if ok give me a ring on01977610578 ken hudson kenny


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## sunsaz1

OK - think we get the message - will get it sorted asap.

Thanks again for everyones advice.


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## sallytrafic

sunsaz1 said:


> We are obviously not electricians and all this is a bit above our capabilities (as if you hadn't guessed).
> We went to a local Motorhome service and accessory centre and they didn't know what to suggest and are too busy to look at her in the near future.
> Could it be that we have a live connection touching the bodywork of the van or could it be that the earth on the van has a bad connection?
> Any suggestions are very welcome.


It can be both.

It is very difficult to explain without over simplifying it but here goes.

50milliAmps (mA) across your heart will kill (true for 95% of the adult population). It is the voltage across you that drives the current through you so for example if your left hand is touching 230V and your right hand is touching zero volts there is a good chance that over 50mA will flow and kill you.

A mains supply consists of a live wire and a neutral wire. At the supply companies substation live is around 240V and neutral is connected to earth and we say it is 0V. All the current coming down the live wire should pass though your equipment and return along the neutral wire. Any current that doesn't come back is most likely to have leaked to earth.

An RCD trip detects any 'missing' current and if it is more than 30mA disconnects the supply. This is in case that 'missing' current has passed through a human being. Any mains supply going outside a dwelling should by the wiring regulations be protected by an RCD. This is why people are surprised that you are not tripping the supply.

Assuming no RCD (or a faulty one) then if there was a direct short between earth and the live lots of current would flow and a breaker would trip or fuse would blow. Clearly that isn't the case.

So the most likely fault is that the live conductor was in some place allowing a little current to leak to the body of the van through a low resistance path (say a frayed cable) and you were completing the circuit by touching the van and standing on earth.

Now by swapping the live and neutral you have not removed the fault all you have done is masked it. There is still a low resistance path from your cabling but because Neutral is near 0 Volts there is less chance of a shock. However we do not know if you will always be connected to a correctly polarised supply. The next supply you connect to may be the opposite way around and that could kill you. Also if for any reason the neutral cable becomes disconnected then (for reasons beyond the this simple explanation) the voltage will dramatically rise towards 240V. This also could kill you.

If the cable is frayed the fraying won't get better it may get worse.


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## pippin

I am afraid that I have to say that the advice given by Kenny is 
HIGHLY DANGEROUS.

It might be OK for him as a retired electrician to connect a bulb in the manner that he has described but for someone else who is not aware of the precautions needed then it is 
HIGHLY DANGEROUS.


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## Penquin

Totally agree with what Frank is saying - the potential for lethal shock is VERY high and the current required to induce venticular fibrilliation in some people lower than 30ma.

http://www.pat-testing.info/electric-shock.htm

This PAT testing article is a statement of the dangers - PAT testing (Portable Appliance Testing) is party of the framework of regulations put together to cover employees by the Institute of Electrical Engineers in response to requirements and observations by the HSE.

In some conditions a current as low as 1ma could be fatal, it is not worth the risk.

As so many have said;

*SWITCH OFF *and *DISCONNECT* rom the mains supply. It is not safe to remain connected until the fault has been identified, isolated and resolved.

It may not be you that suffers, but anyone touching your van e.g. a child or visitor.

I doubt that your insurance company would be over impressed if someone was seiously injured or worse and it came out that you knew there was potentially a problem.

I am sorry if that sounds severe, it is meant to be. I work for the ambulance service as an emergency responder and if you were in my area keeping you alive could be my task in the middle of the night. Electricity has a reputation for being dangerous - you are playing with fire to say the least.

*GET OUT *and *SWITCH OFF* is the only option.

Dave


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