EHU with open earth

[alwaysared]

In normal use there is no adverse consequence to the majority of appliances. Just be aware that when switching an appliance off at a socket or switch that it is the Neutral that would have been switched and Live would still be going to the appliance.

I believe that most appliances are now double pole, ie they switch off both. There's some good info here

Regards,
Del

 

[rayc]

I believe that most appliances are now double pole, ie they switch off both. There's some good info here

Regards,
Del

But UK mains sockets & MCB's do not. When the socket is switched off live would still be going to the appliance in the event of a L/N reversal.

 

[harrow]

https://www.ebay.co.uk/itm/UK-Mains...386443&hash=item35f432d17e:g:ds4AAOSwjVVVpkbh

Now that's an interesting point because this thread talks about already knowing using an ehu point that you know has no earth connection.

If you use one of the plugin testers you describe it applies a voltage and current to the earth pin in the socket in your bus.

If you know there is no earth connection the described tester applies a voltage and current to the metal body of your camper and you WILL get an electric SHOCK.

:voltage_emoji_icon_:Very_sad_emoji_icon:voltage_emoji_icon_

If you want the full explanation see,

https://www.youtube.com/watch?v=_KOYt-0WZxg

and find out why Fluke testers are withdrawing this tester

 

[rayc]

If you know there is no earth connection the described tester applies a voltage and current to the metal body of your camper and you WILL get an electric SHOCK.

But surely only if you have hold of the camper metal body and you are earthed at the same time? It is explained at 19.25 onwards in the video.
The choice is of course that if there is no earth AND you get full Live mains voltage to the metal body by a fault in an appliance AND you grab the body whilst being earthed then you could get a very big shock. I would though have expected the RCD to have operated in that scenario.
Personally I will stick with my voltage tester whilst not holding the metal body at least then I will know if the earth is missing and take appropriate action.

 

[harrow]

But surely only if you have hold of the camper metal body and you are earthed at the same time? It is explained at 19.25 onwards in the video.
The choice is of course that if there is no earth AND you get full Live mains voltage to the metal body by a fault in an appliance AND you grab the body whilst being earthed then you could get a very big shock. I would though have expected the RCD to have operated in that scenario.
Personally I will stick with my voltage tester whilst not holding the metal body at least then I will know if the earth is missing and take appropriate action.

NO.
If the is no supplied earth.

And you plug your suggested tester in.

Mains voltage is applied to ANY earth on the camper be it a metal sink cooker or metal bodywork.

That why the tester is being withdrawn

 

[rayc]

NO.
If the is no supplied earth.

And you plug your suggested tester in.

Mains voltage is applied to ANY earth on the camper be it a metal sink cooker or metal bodywork.

That why the tester is being withdrawn

Yes but you will not get a shock unless you are making a path to earth via the metal sink or metal body. If the incoming earth is missing the tester will apply a small current to the earth pin which as you say will be fed to all earth points. unless your body makes a route for the current to get to earth, i.e you stay in the motor home, then you will not get a shock. Like birds on a pylon wire.

 

[harrow]

Yes but you will not get a shock unless you are making a path to earth via the metal sink or metal body. If the incoming earth is missing the tester will apply a small current to the earth pin which as you say will be fed to all earth points. unless your body makes a route for the current to get to earth, i.e you stay in the motor home, then you will not get a shock. Like birds on a pylon wire.

Unless your tester is plugged in and someone touches the door, bodywork, door handle etc at that point the metal bodywork is live.

 

[rayc]

Unless your tester is plugged in and someone touches the door, bodywork, door handle etc at that point the metal bodywork is live.

But presumably the tester would have shown the earth fault and as a result the EHU lead would have been disconnected? Not much point having a tester if you do not act on what information it is giving. Without the tester how would it have been ascertained whether there was a fault with the supply or unit installation in the first place? The video is interesting and the summing up of the guy from 19.30 on wards is sensible. He starts by saying "mmmm .... it's just collateral damage of this type of tester........."

 

[Jezport]

DON'T run your fingers across the handle use the back of your hand. If there is a fault and you touch it with your fingers your muscles can contract and make you grab the handle and be unable to let go.

Only true on a DC Current not AC

 

[rayc]

Only true on a DC Current not AC

Interesting. This document says "How AC affects the body depends largely on frequency. Low-frequency (50- to 60-Hz) AC is used in US (60 Hz) and European (50 Hz) households; it can be more dangerous than high-frequency AC and is 3 to 5 times more dangerous than DC of the same voltage and amperage. Low-frequency AC produces extended muscle contraction (tetany), which may freeze the hand to the current’s source, prolonging exposure. DC is most likely to cause a single convulsive contraction, which often forces the victim away from the current’s source."
https://www.allaboutcircuits.com/textbook/direct-current/chpt-3/physiological-effects-electricity/

 

[TissyD]

Only true on a DC Current not AC

It's a long time ago but when I was a squaddie we were told AC from the genny could do it and always use the back of your hand.

 

[nabsim]

So, is the consensus for a quick fix to bang the dog spikes in the ground and connect jump lead as suggested by Jeffmossey then?