Reversed polarity
Comments
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Whilst it may be common practice in Spain for home owners to have to supply earth rods it would be extremely bad practice not to wire in an Earth to an EHU point on a commercially operated site. Of course, I cannot quote Spanish standards but I would be
fairly sure that it is a code requirement and may even be a legal requirement. Perhaps older sites are lax.Unfortunately there is no easy way to check because if they are using the supply system I described earlier then your detectors will give a false reading.
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Whilst it may be common practice in Spain for home owners to have to supply earth rods it would be extremely bad practice not to wire in an Earth to an EHU point on a commercially operated site. Of course, I cannot quote Spanish standards but I would be fairly sure that it is a code requirement and may even be a legal requirement. Perhaps older sites are lax.
Unfortunately there is no easy way to check because if they are using the supply system I described earlier then your detectors will give a false reading.
IEE regulations stipulate that campsite EHUs must have a local earth plate or spike to provide the essential connection to earth ( see also CC advice to campsites), and not via the earthed protective sheath/ neutral line as is done for houses in UK. Every campsite EHU, including those in continental Europe, should have a local earth to which the earth pin in the outlet is connected..
RCDs depend on all the metalwork of a caravan or motorhome, excluding external panels, being bonded to earth. The RCD are there to trip the supply before anyone makes contact with a metal surface which has become 'live' through damage, loose connection, entrapment or insulation failure.
As a matter of interest ( to some?), our daughter's house in the Alpes has an earth plate and a link which EDF can remove to test the efficacy of the grounding.
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Sorry Chas, but RCD's do not need an earth to work. They operate by comparing the current in the neutral and phase conductors and where there is a difference, indicating a leak to earth, for example through your body, then they will trip.
Of course, if the appliances in the van are connected to earth via the earthing conductor in the cable and the EHU is earthed and a metal part of the appliance becomes live then the rcd will trip before anyone touches a live part. Clearly this is better
than the case above as the RCD will trip before anyone comes in contact with a live part.Earthing your van will avoid what in the States is called "hot skin" where the metal bodywork becomes live from a fault in the van's wiring.
Many appliances are also double insulated and do not need an earth and are much safer than those which are earthed.
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If there is no earth connection to the van/vehicle then it is actually "floating" and in theory there is no earth path back to the supply so no earth fault protection works! I wouldn't like to test it though because the earth is a large capacitor so if the
outside skin of the van is live it could be quite uncomfortable.Earthing practice is quite consistent around the world and for the most part the IEE Regs. are aligned with European standards but there is no guarantee that every camp site in Europe is going to comply, especially the further South you go.
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In this situation, if a there was a fault making metalwork live, and without an earth back to the bollard/substation, you would become "live" and only if you became grounded, eg by stepping outside while touching something that was live would current flow.
If that current was detected by the van's rcd then it would trip. However, if the van skin was live from a fault before the current reached the van's CU then if there was an rcd at the bollard that would trip. If not, you would get an electric shock, which
could be fatal.Earthing the van via a ground rod may or may not work, depending on the length of the rod, ground conditions, moisture content etc.
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GJ, Is a caravan with four steel steadies firmly to the ground earthed? But a motorhome standing only on four rubber tyres presumably not?
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Many vans have load pads so no earth via the steadies. I always take my wellies in the car. Perhaps I should start wearing them.
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This subject is made so vague by the electrical trades even some electricians don't fully undrstand what they are dealing with. Much of the terminolgy is confusing even to those qualified to do work on our systems. Take the phrase "reversed polarity" to
many this means the negative and positive have been switched over - this is nonsense to those who work on DC apparatus since mains are AC and the polarity cannot be reversed since it alternates 50 times a second between negative and positive on any mains
regardless of how it is connected to the van. However, following a controversy on another site it seems the people, electricians, who work on them are told that the term ' polarity' is used when refering to phases in AC systems. If you consider an electrician
giving you advice on electrical safety and is taught refering to highly technical references where there is many variations that affect the safety little wonder that they get confused. An excellent description of these systems is posted on YouTube by John
Ward and completely clear up any confusion and many electricians have had their understanding improved.0 -
@eurotraveller, tyres are a good insulator. Steel steadies straight onto the ground will provide earthing, depending ground conditions.
Perhaps too much fuss if made over "reversed polarity" since, as pointed out above it's really just a convention. Appliances will still work.
The 2 pin continental adaptor can be inserted either way at the bollard connection, regardless of polarity, but there should be a double pole isolator at the bollard.
The danger comes when there's a fault and people start fiddling around with the appliance still plugged in and without disconnecting the electricity at the bollard by pulling out the EHU cable.
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The steadies are usually up when one sites the van and I would hazard to state most people connect electricity before doing anything else. And many vans now have steadies fixed to the floor independent of the chassis.
There are fatalities every year where people using lorries and construction plant are killed after their apparatus touches overhead wires, but only at the point where they get out to investigate. The current that is required to kill is less than that to
trip out the distribution equipment.Normal usage works fine until in the heat (no pun) of something going wrong people go beyond their level of understanding.
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"The 2 pin continental adaptor can be inserted either way". Not always true as in France the 'Two Pole and Earth' plugs, as they should correctly be described, have a socket which mates with an opposing earth pin in the socket outlet as well as earthing
strips on the outside of the plug. Elsewhere in Europe, the earth connection is made solely by the metal strips, and the plug can be inserted either way.0 -
It's actually quite difficult to create a proper earth and requires a deep pit, conductive filler (like Bentonite) and a deep earth rod. Steadies will not really do the job, partly perhaps on wet earth but certainly not on dry earth.
The reason people have been killed with cranes, cherry pickers etc. touching overhead lines is that said lines are generally thousands of volts, not a domestic supply.
As has been said several times above, inside the van the rcd will do its job (if it is functioning correctly) earth or no earth. It there is a fault up to the incoming isolator in the van and the exterior or chassis becomes lIve
then you are relying on the EHU Earth fault protection. If there is none then you have a "touch voltage" on the van that may or may not be a problem but which is clearly undesirable. Of course, if you have a proper connector and cable with no loose wiring
or bad insulation then this scenario would be unlikely.0 -
@chasncath - thanks, not used EHU in France.
As has been said earlier, basic socket testers may not give accurate results in Spain where different systems to that found in the UK may exist. So without thorough testing the "no earth" situation may not actually exist.
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