EHU question.....

As I am hardly ever likely to hook up in any country, I'm not too fussed to tell you the truth. But if I ever do I know that I have my reverse polarity lead to fall back on should my Chausson go into meltdown.
 
In a properly designed system with correct polarity all the single pole switches and fuses will be placed in the live lead this ensures that if all the MCB's and RCD's fail the fuse as the last and most important protection system will blow cutting off the power in the live or phase lead. However if all the mechanical protection devices were to fail and you have reversed polarity all your single pole switches and fuses are in the neutral lead (as the polarity is reversed) and in the event of a live conductor (which is actually now the ex neutral lead) to earth fault the fuse wont blow and the switch wont cut off the power as they are now both in the neutral lead so the only thing left is for the thinnest cable in the circuit to overheat and burn out. Or if the earth lead is missing the whole of the van chassis will become live with respect to earth possibly causing a shock. This will probably never happen because the RCD or the MCB will most likely trip however never rely on a mechanical device to save your life it helps, but a correctly wired up system is designed to be wired with correct polarity for basic safety.
 
I'm not an electrician but I do own a Motorhome, a Lunar Premier with a Calira EVS 38/20-DS/IU Electric System. I've spent the last half hour reading the manual and I'm still a little confused so I would appreciate any advice from you folk who obviously know what you're talking about. I'll quote from the handbook: "The power supply is microprocessor-controlled switched-mode power supply technology" and "is designed for parallel operation and buffer operation". Now, I think this refers to how the starter and leisure batteries are charged and I'm struggling to find any reference in the manual as to whether the system is "safe" if the polarity is reversed. I have recently come across electricity supply in Morocco where the polarity was reversed ( I knew this after checking with a plug tester) and where possible inserted my plug "upside down". This wasn't always possible however but remembered reading here some time ago on another thread that I shouldn't be worried about reversed polarity so connected to the supply anyway and I'm still here to tell the tale. Nobody died and nothing burst into flames. Was I just lucky or should I be seriously concerned about using hook up electric supply with reversed polarity? Or is my equipment designed to cope with reversed polarity?
 
My experience of French hook up users differ somewhat to yours,I have seen so many cable spliters being used it is mind boggling,cables running all over the place, ordinary domestic non waterproof plugs and sockets in use, left out in the rain or wraped in plastic bags so condensation can form, of course we all make choices. Mine always err on the safe side,to say that crossed polarity is not unsafe is a very stupid statement ,and to suggest to someone that does not understand electricty and its regulations, that they tinker in their consumer units with a mish mash of components is even worse.
 
As an electrical engineer and pretty experienced motorhomer in more than 20 countries, I guess I should know better but I have given up worrying about "reverse polarity", presence or absence of an earth, or whether the campground circuit has fuses, circuit breakers, earth leakage breakers or whether they or the ones inside of my vehicles are single pole or double, or whether there are 35 RVs plugged into a single circuit or if there are 6 French MHers daisy chained off my extension reel or any other combination or permutation.

IMG_3935.JPG
Standard accessories for any American RVer.

Electrical%u00252520Outlets%u00252520Marrakech.jpg
Looks good but no earth and no useful overcurrent protection

DSCF6841.JPG
(Not as bad as it looks because there is no earth conductor to the power outlet anyway.
When I went to bed there was just mine plugged in, but by morning the power board was getting a bit crowded.
Mine at the top, an Argentinain's in the middle and a German who just crossed from Chile and who was having adaptor problems on the bottom.
We all lived through the experience)

Lots more "amusing" photos like these
The only really safe system would be to have a double insulated multi-voltage switch-mode battery charger installed in a separate insulated compartment and use that to charge the batteries and act as a power supply to feed all the 12V circuits and an inverter that supplies essential mains appliances on board. A small on-board generator - permanently wired - could supply any big stuff.
That way it wouldn't matter too much what sort of hookup you were using because it can't compromise your fixed installation in any way..
 
Reading these previous posts gives me a headache just trying to understand them.

EHU & polarity problems don't affect me, I have a couple of solar panels & don't near campsites.

Even if on an aire with EHU, I still don't bother as my cable is right at the bottom iin a under- seat locker.
 
Oh my gawd, I really started summat with this thread didnt I? Thought it was gonna all be so simples! Had a few campervans years ago.Never bothered with elec hookups(werent many around then anyway).Never had second battery, but ran an old style 12v tv, strip lighting, and water pumps without once draining the vehicle battery.TBH , didnt even think about it much. Did have a split charge set up once comprising of another vehicle battery wired with doubled up 2.5 cable through a 30amp cooker switch, manually operated.Couldnt be bothered to keep switching it so left it off. Only occasionally visited sites, mostly wild camping , but it wasnt called that then, it was just parking in a sea front car park, and having fun with the kids. Im not sure if things have advanced for the better or not tbh! (No disrespect to anyone on here btw)
Yes it is good to have all the mod cons, but with them come all the advanced probs which is another headache when its really all about having fun .
 
Last edited:
Yes, when reversed polarity enters a topic you will get a multitude of opinions some of which very questionable. With some of the experts I would not allow them to fit a plug safely, as believe me there is a correct way and only if you have been trained properly would you understand. 😁
 

Users who viewed this discussion (Total:0)

Back
Top