View Full Version : French electrical connector polarity. Advice, please!

26-08-08, 19:11
I recently bought a French petrol generator. Its connector socket is the usual 3-pin French type with female sockets for live and neutral and a male earth pin. It is rated 16 Amp and marked IP44.

It came with a plug but no cable. I want to connect this plug to an extension lead with a British 13Amp socket.

There is no indication on the French socket and plug to show which is live and neutral. I could run it and check with a meter but I have no petrol handy at the moment and I wanted to wire it up this evening.

Can someone advise me how to identify live and neutral on the French connector, please? Or maybe it isn't labelled because it doesn't matter?

Anyway, advice would be appreciated.

26-08-08, 19:29
From the internet:

How do I wire a French plug?

There are two types of plug; a two pin plug for unearthed equipment and a three pin plug for earthed equipment. You should only use a two pin plug if your cable only has two wires; one black (or brown or red) and one blue. If there is a third wire (yellow and green) then use a three pin plug.

Two Pin Plugs: Connect each of the two wires to a different pin. It doesn't matter which way round because the French system has no fuse in the plug.

Three Pin Plugs: The earth will be marked (and is always the female pin in the centre top). Wire the green and yellow wire here. Then connect the other two wires, one to each of the other (male) pins. Again it doesn't matter which way round.

The above is what I found from the net .......... I take no responsibility for the accuracy of the information.


26-08-08, 19:40
It does not matter to the French because their electical goods are double pole switched. What you need is a polarity tester (sold in caravan shops) Wire your adapter, run the generator and plug in the tester. If it shows line and neutral reversed, swap the wires at the plug. A mains tester screwdriver will also reveal which is the positive if you do not want to buy a proper polarity tester plug, but the latter is very useful in revealing other faults such as no earth.

26-08-08, 19:54
Fine for the French, but UK equipment is switched on the Line connection only, therefore line and neutral reversed is a potentially dangerous condition. At worst it can leave the metal parts of an item which is switched off electrically live. Most caravanners who go to France use something like this (http://www.campingandleisure.co.uk/catalog/product_info.php?cPath=6_21&products_id=197) to check polarity when connecting to site mains, and either use a connector with reversed wiring or a changeover switch to correct any problem.

26-08-08, 20:30

Thanks Norman and Alan.

26-08-08, 20:36
Based on an inverter we bought a while back (2002) which had a continental power connector, both sides of the French power supply can be live at the same time (like USA 220v which is earthed in the centre, making both wires live at 110v from earth), hence the switches on sides.

We blew the inverter up by as we thought making it safer by connecting one side of the mains output to battery - and earth.

It turned out that it would have blown if either side was earthed because of the way it produced AC by connecting + 340 volts (pseudo sine wave) to live then neutral in turn, and earthing neutral then live in turn at 50 Hz...

An internal re-wire might be needed with the generator to
make sure one side of the output is near earth (= neutral) all the time.

Otherwise an isolating transformer might be a safe option, or a Frenchman who needs a generator.

26-08-08, 20:57
I don't think French mains supply is like the US 110 volt system (which gives 55 volts to earth on each "leg"), as when I go to France with the caravan, the mains tester will always indicate a normal UK type condition of the mains connection, or line and neutral reversed (in which case I just press my polarity changeover switch). Of course a generator could be wired with each side of the socket giving 115 volts to earth on opposite phases, making 230 volts. If so it would be inherently dangerous to use with any UK appliance no matter how it was connected. A tester plug should reveal the truth, though I am not sure what lights it will display if two terminals are both live. A second check with a mains tester screwdriver, which should light up when applied to one terminal only, appears called for.

27-08-08, 06:11
You don't need to run the genny to discover if one output is live and the other is neutral. Just check the resistance between the earth line and each of the supply lines.

If both resitances are infinite (quite a common situation in generators) neither side is 'neutral', and both are 'live', but only relative to each other. It then doesn't make any difference which supply line is connected to which (supply) plug prong.

If one supply pole shows open circuit with 'earth', then the genny frame/earth is connected to that pole, making it the local neutral. In this case many would recommend you earth your genny when it's in use with a stake or a line into the water.

27-08-08, 07:13
Sockets should be as UK, Bottom rt. Live. Bottom left, neutral.
Middle top(male pin) earth. BUT, I have found frequent live `neutrals´ while rewiring the house here. Genny should be isolated as said above. I have never trusted any system to be as it should. Tester always to hand.:-)

27-08-08, 11:27
It does not matter to the French because their electical goods are double pole switched.

[/ QUOTE ]

Er;- no! Not in my pad anyway. French electrics leave a lot to be desired. Until recently they relied on trip switches for protection without an earth! I.e. the trip only operated when an external connection was made from a faulty appliance through an external connection;- i.e. a body. A lot of people survived.

Neutral should be connected to earth at or before the source of supply (as UK standard). If you check for voltage between the earth pin and the other two, you should find zero volts on the neutral and 220-230 on the live.

27-08-08, 13:19
As Jim Baerselman says, most (all?) small generators use a center tap earth and the mains voltage is alternated between the other two pins, so they can't be called 'live' and 'neutral' and neither are (or should be) connected to earth.

27-08-08, 19:55
Not exactly. Most connect the frame of the genny to the earth line, so that the genny frame (and all the metal work attached) is a local earth. I'm not aware of any practice of 'centre tapping' for small petrol gennys, but then I'm not an electrical professional.

Some then go a step further, and connect the frame to one of the feed lines, making that feed line a neutral - relative to the frame.

If you're distributing power outside the limits of just the genny plug (ie, sticking it into your boat's power input) then you should earth the genny frame fully- into the sea by any suitable route.

Some info on American Genny earthing arrangements (http:// ators&hl=en&ct=clnk&cd=4&gl=uk)

27-08-08, 21:03
'Not exactly' - how kind, more like utter crap!
I don't know where I got the center tap earth from, it must be age /forums/images/graemlins/frown.gif
But the other but was correct.

This is what mine looks like: