I'm in the middle of wiring up a cable for an electrical hook up to be used while camping in France. I have a French 3-pin plug bought there on a previous visit, but in opening it up I find there's absolutely no indication which of the two power pins is live and neutral. Doesn't it matter?
I will be using the cable with an RCD device; won't that object and trip out if the wiring's the wrong way round? Or is it a case of "suck it and see" when I get to France, and if it's wrong, reverse the wiring?
You can get the proper adaptor from a caravan shop or Towsure, but be careful some sites in France use the same blue plug as our sites, I have 3 different adapters - two with the French plugs, one with reversed polarity and the other as normal then I also have a short lead of male and female blue plugs with the polarity reversed because 'yes' I have come across that aswell! Its also useful having a blue plug with a uk three pin socket on the end so you can plug a tester in to test for correct polarity or earth faults before using the correct adaptor to hook up. Steve.
If you're referring to the standard french domestic socket outlet, it's not defined which way around the live and neutral are. Actually, on most 2-way adaptors and double socket outlets, you'll find the two sockets are hard-wired internally the opposite way around.
Some do, but I don't think that's a common feature.
Thanks for that. What a palaver! Yes, I already have a conventional UK-style cable with blue plug; what I'm actually wiring today is a short adapter, ie with a blue socket to a French plug.
Hmm, a plug-in tester sounds a good idea, now. However, I'm not going to have time to sort out further hardware as I leave for France tomorrow
- so in the meantime can you or anyone else confirm what happens if I plug in the cable with accidentally reversed polarity? Will it just trip the RCD device, so I can just rewire the plug? If not, what will be the effect of getting it wrong... electrical items to be used include a fridge, laptop, phone chargers...
A number of years ago when caravanning in France/Spain I was warned by a friend about polarity problems when using an RCD. I fitted a switch (DPDT) the the (old) van so that I could easily change polarity. Sure enough on one site in France when a new arrival plugged my leadinto a different socket on the same set of sockets I discovered that the system had trippedbecause the polarity was reversed. On a site in Spain this polarity reversal happened without the lead being unplugged!
You need three adaptors
16A blue to 16 A blue, polarity reversed
16A blue to continental
16A blue to continental, polarity reversed
If the RCD trips and won't reset, reverse the polarity. Our continental cousins don't have the concept of live and neutral that we do
RCD devices only look for a difference in the current flowing in the two connections. It has nothing to do with earth. You may however find that the test button does not work if L & N are reversed as I think all this does is to connect a resistor between the live and earth. This might only provide enough trip current if the live is truly live.
OK, thanks - think I've got it now! Will organise some more hardware before my next trip.
I don't intend to use any power without an RCD, but just for my education and information, if I *were* to do so, would all my kit (laptop/fridge/chargers) all work OK without problems, then?
What do the French etc do about this polarity problem - do they not bother with RCDs while camping or whatever?
Generally reverse polarity will make little difference to 230 volt appliances in good working order. The problem with UK appliances occurs if the appliance has a fault and remains on when you think it is off as we only switched on the live side. Mind you newer caravans don't seem to have socket switches now which makes it a bit more difficult. If its any help this is how I have explained it on my website
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The best option is the have a short cable with CEE17 male and sockets at either end with one end reversed. This can then be used with either you manin cable or with the continental adaptor. At least that works for me. Have a good trip.
As has already been said, the RCD looks for a difference in the currents in the live and neutral. If there is an imbalance, it assumes the current is flowing to earth somewhere (which it should not be) and trips out. Therefore it will make no difference which way round the device is connected. Also, the connected equipment cannot "tell" which way round it is wired - the current is alternating! In the UK we like to know which is which for safety reasons - if we switch off equipment by breaking the neutral, the equipment will be off but still at live potential which could be dangerous for anyone poking about inside. However as much of Europe uses 2 pin reversible plugs it can obviously be connected either way.
I'm really amazed at the low standard of Italian plugs. It makes one wonder if the fuses in UK plugs are really necessary. There are meant to be two kinds of 3-pin plugs, for power and lights, but all the sockets I have seen accept either.
Has there been any EU attempt to define a European standard plug?
Now, that's a whole can of worms I never really got my head round.
*Why* do we have one leg ( Neutral ) referenced to earth?
The down-side is that if an appliance develops a fault such that the case becomes 'live', an earthed person gets a whack. We then go to great lengths to earth the cases ets etc, so that fault current will trip something, clearing the danger.
Why don't we float the whole system WRT earth? Then it doesn't matter if an appliance becomes 'live' WRT earth.
Aside: I just got back from Namibia and Botswana. I was peering at their overhead 11Kv distributution system. All very similar to here. With an interesting exception.
There were long runs of *single* conductor HV on poles, along the rural gravel roads. There were transformers dotted around on poles, feeding individual premises. I never got a good look at one of these transformers. Now, how does that work? They must be using TT earth as an actual current return, on the HV side, as far as I can see. I wonder how they make the local HV earth connection with sufficiently low Z in the very dry earth?
Further confirmation was at one lodge, where an old transformer was laying outside the services building. ( I'm sure everyone thought I was crazy, polishing the muck of the data plate of an old transformer in the corner.. ) The rating plate had the single phase primary as 6.3Kv, which is consistent with the Phase-N voltage of an 11Kv Phase-Phase system. There must have been 1:1 Star-Delta transformers someplace on the main network, where the normal 11 KV 3-wire delta distribution spurred off to a star 11Kv 3-wire +N ( 6.3Kv per phase-N ), and the N was grounded. Only the single phase was sent on the wire.
The reason for earthing one side of the mains is that by so doing, you prevent the mains from floating to a dangerous voltage due to leakage in the substation transformer, or indeed faulty appliances owned by somebody else off the same feed.
Several, all failed (except for standardising a 2-pin plug which we don't use in the UK), although I may be out of date now.
Basically, no one is prepared to change, and everyone believes (without any evidence to back it up) that theirs is the best system. It's not just the plug -- the design of that is linked to the design of the electrical distribution and protection systems, and these vary widely across Europe. The UK BS1363 (13A) plugs and sockets are the most recent of the established designs for mains appliance plugs and sockets in the world (1946). All other systems predate that, some by a very long way. BS1363 is also quite widely adopted around the world, although in Europe, only in UK, Ireland and Malta.
I loosely followed the first attempt. EEC (as it then was) placed the requirement than the new plug/socket had to be different from anything currently existing so no country derived unfair commercial benefit (and there are good technical reasons for that too), and it had to be no less safe than any of the existing schemes. That got nowhere. Last I heard (which was probably at least 6 years ago), there had been 5 attempts, all failed. In practice, standardisation has taken place at the other end of the cable, i.e. the IEC mains inlet connectors.
In the commercial arena, the british commando BS4343 plugs and sockets have been universally adopted as no other European country had anything much of an equivalent standard. Even the US have adopted a variant of them (different ratings).
What does "floating to a dangerous voltage" mean? To a dangerous voltage with respect to what? Earth? A floating system has undefined voltage WRT earth.
I'm trying to imagine an actual fault scenario, where a floating L-N pair can float to a 'dangerous voltage' WRT earth. If the whole system is floating, then there's no such thing as a 'dangerous voltage'.
Hmm, perhaps if one leg leaks to earth at the substation, then the system no longer floats, and there's the possibility of shock WRT earth.
UK Electrical workmanship standards differ from Europe we have neutral and earth return, The europeans don't have an earth linked into the substation/generating station neutral as we do. in fact they don't use earth return at all.
I was involved with a transformer company a few years ago which used to manufacture mains test lamps for amongst others RS componants ,very simple if there was voltage they lit up, cost pennies and all the electricity boards used them.
Overnight the EEC brought in rules on the test equipment that could be used , they cost about £50 each, (I am sure due to pressure from a German test manufacturer), but due to the differing workmanship practices in the UK were not as efficient. Our observant Goverment didn't even notice!! (or didn't realise the impact), nearly put the company out of business (CE mark and Insurance) Eventually they managed to get an exemption to the rules for a few years.
Most modern mains electrical equipment is double insulated and doesn't matter which way round it is wired (live/neutral), don't forget it gets supplied to Europe as well. If you are concerned get a polarity live/neutral tester and carry adapter plugs wired to suit both polarities.
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