Anyone with experience of French electrical installations?

[Penners]

An English friend who lives in France wants to renew some wiring in his house. He tells me that the French use radial circuits rather than ring circuits for the normal household sockets.

The French regs apparently require any wall socket to be supplied with 2.5 TW&E cable. However, it seems to be acceptable for a typical radial circuit to a room to consist of a single supply cable from the consumer unit to a junction box within the room, with spurs then running from the junction box to the various sockets in that room.

The only detail that he hasn't been able to ascertain for an arrangement like this is: what weight of cable should be used for the radial circuit between the mini-breaker and the junction box? He is planning to run 4mm TW&E for this single supply, and then 2.5mm from the junction box to each socket. In the unlikely event that anyone on this forum has knowledge of French electrical installation regs, do you know whether this 4mm run is necessary, or would 2.5mm be OK for the whole circuit from breaker to sockets?

Merci beaucoup!

 

[a twig]

How good is your French? Schneider do a handy guide to the regs here that may help:
http://www.e-catalogue.schneider-electric.fr/navDoc/catalog/nf/little/index.htm

There are pictures etc which also help - I think p12 may be of use?

EDIT:
Basically the minimum thickness is determined by whatever else is on that radial.

The example circuit on p34 answers your question. All of the wiring has to comply with the stated table on p12 for that particular circuit.

So my understanding based on your example, assuming it is between 5 and 8 sockets, then the whole lot should be 2.5mm minimum. If you went larger for a section it should be fine.

 

[Keith Bowman]

This ex-pat forum:
http://www.france-forum-frenchentree.com/viewforum.php?f=7
can be quite useful, but beware of know-alls who actually know very little.
The French do not use TW&E cable - they use separate single cables and the earth must be insulated and of the same diameter as the live and neutral cables. I believe he only needs 2.5 square mm from the main fuseboard, but I am neither an expert or a know-all!

 

[Keith Bowman]

PS I also understand that you can only have a maximum of 8 sockets on any one circuit - above that you need a separate disjoncteur and circuit - but the regulations seem to change every time I try to look them up.

 

[Flyfisher]

I know nothing about French wiring regulations.

However, given that French appliance plugs are not fused then the only over-current protection for any circuit is the MCB (presumably) in the consumer unit and that MCB should be rated to protect 2.5mm2 cable if that is the minimum in the radial circuit.

Thus, the maximum current that can be drawn by the entire circuit is limited by the MCB and is safe for 2.5mm cable and, therefore, using a 4mm cable at any point in the circuit should not be necessary.

I say 'should not' because there might possibly be cable length, thermal de-rating and volts-drop considerations, depending on the precise wiring configuration, but in a typical house this would probably not be the case.

As I said, I know nothing about French wiring regs but let's assume for the moment that the fuse rating (MCB) for a 2.5mm radial circuit is 20A. That means a maximum of 20A can be drawn by all the sockets on that circuit. Thus, there can never be more than 20A flowing in any part of the wiring at any time (or the MCB will trip) and since 2.5mm2 cable is deemed adequate for this there is no need for 4mm2 cable to be used anywhere in the circuit (subject to the above possibility of long cable runs etc).

But that's from a circuit design perspective and might not necessarily tally with French wiring regulations, about which I know nothing.

 

[FamilyWiggs]

The regs as far as I understand them involve:

a) Lighting a Gauloise;
b) Setting fire to some British lamb and blockading a port;
c) Going home early for the day/weekend/summer complaining of the ardours of a 33 hour working week.

Tres bien.

Apres la deluge and all that.

 

[Owain]

The French wiring regulations and the British ones are both EU-harmonised, and so an installation to either set will be compliant. I've heard of French inspectors accepting an installation to UK regulations.

Main areas of difference AIUI:

- no reduced size or uninsulated earth: all conductors the same size and earth in a cable is insulated g/y
- double pole MCBs as socket polarity is not guaranteed
- 16A socket circuits with fewer sockets per circuit
- French regulations now require Ethernet type cable from various locations to a central hub point, even if it's not connected, for future use.

 

[Keith Bowman]

The French wiring regulations and the British ones are both EU-harmonised, and so an installation to either set will be compliant. I've heard of French inspectors accepting an installation to UK regulations.

Main areas of difference AIUI:

- no reduced size or uninsulated earth: all conductors the same size and earth in a cable is insulated g/y
- double pole MCBs as socket polarity is not guaranteed
- 16A socket circuits with fewer sockets per circuit
- French regulations now require Ethernet type cable from various locations to a central hub point, even if it's not connected, for future use.

Having had a house in France for the last 15 years which we are in the process of selling, I can assure you that whatever the 'harmonised' position might be, in practice the inspection which is legally necessary before sale can report unfavourably on any British fittings ("is not the norme francais") and wiring which is not to what they regard as up to french standards. Of course one could argue the point - but they also inspect for lead paint, asbestos, insulation/energy efficiency and a host of other things and an upset inspector has the ability to be a right nuisance just at the moment when the prospective purchaser is looking for arguments to reduce the price!

 

[Keithj]

In theory, it's all European now. In reality, it's not - especially in France. I've not wired in France (I have in Germany) and some of the regulations seem a tad contrary (just like some aspects of Part P here).

If you can find a local bloke who is happy to advise, and maybe sign it all off afterwards, that may work. Otherwise, buy local 2-pole MCBs, cable (not T&E, which seems to be a uniquely British thing) and sockets etc. They mostly use those daft German-origin Schukostecker - which are reversible, held in the wall by a claw which works loose, and look very skinny to someone used to good 13 amp ringmains.