February 2008

Don't hide away....

If I had to name one aspect of the domestic wiring regulations in France that underlines their common sense it is the attitude to junctions/joints in any circuit.

The rule is incredibly simple; any joint in any cable or wire must be accessible.

In other words there is no opportunity for a cable to change size or colour or split without it being obvious by opening a junction box ("bôite de derivation"). Unlike the UK you cannot hide a juncton box under a floor, sealed away beneath boards, carpets or laminate flooring. This regulation explains why you find so many flush fitting junction boxes on the market, to be buried in solid walls or plasterboard ceilings & partitions. On the surface these are just a plain white plate, which can be painted to suit. As a box has to be accessible it is forbidden to paper over them (but you could stick wallpaper to the lid to match in, as long as the screws are left exposed). This all means that anyone investigating a fault doesn't have to be responsible for damaging any precious decor. It is allowable to have junctions behind cupboards/kitchen units etc., as long as their prescence in indicated somehow. Access can then be via a removable panel, or removal of the shelf, picture or whatever, that is concealing the box.

A junction box is not limited to being used by just one circuit. If circumstances create the neccessity it is perfectly normal to have a large junction box containing links/pairing/switch loops for sockets, lighting circuits, heaters & any other circuit of the same voltage. This gives rise to the large "bôite de combles" that you might have seen on the shelves of a brico store; these are intended to be fitted in voids (combles) as a hub for anything that can be serviced from that void. The result of such a box with multiple flexible conduits radiating out from it is sometimes referred to as a "pieuvre" - an octopus!

In order to help future fault finding of, or alterations to, wiring, it is imperitive to lable the circuits within a junction box (or anywhere else for that matter). Failure to do so will could result in the poor soul who has to deal with the system at a later date hunting you down & doing unspeakable things by way of revenge. You have been warned.

Sockets & their wiring - Part 2

As French socket circuits don't use the UK ring main principle (which allows the quite large rating of 32 amps) the number of outlets allowed on any one circuit is limited. There are two sizes of wiring allowed for use with sockets, which creates another level of restriction. For the moment please assume that one socket means exactly that - a single socket outlet.

Circuit wired in 1.5mm² cable: maximum number of sockets = 5.
Protection must be via a maximum 16 amp rated MCB (disjoncteur divisionnaire) only - no fuses are allowed.

Circuit wired in 2.5mm² cable: maximum number of sockets = 8.
Protection can be via a maximum 20 amp rated MCB (disjoncteur divisionnaire) or fuse of 16 amps maximum.

That's all fairly simple...... However, if you feel that only having 5 or 8 outlets on a circuit is really going to cramp your style, or create a silly number of circuits, don't panic! You are allowed to count double sockets as a single outlet, so your circuit of 5 sockets can actually be 5 doubles = 10 physical places that you can plug in to. A triple outlet counts as 2 sockets, as does a quadruple one. The reasoning for this seems to be that if you have 5 sockets strung out at 3 metre intervals there is plenty of scope for each one having a fairly hefty device pugged into it, whereas doubles are more of a convenience to plug in several small devices in the same location (TV & satellite box for example).

As no ring is involved when wiring a French socket circuit there is no need to string one socket after another in a "daisy chain" fashion. In other words, if it was physically convenient you could take the circuit from your consumer unit, daisy chain through two sockets, then into a junction box where another 3 outlets are wired out as individual runs in a star, or radial format. Just observe the rules about junction boxes, but that's a subject for another rambling.....

Sockets & their wiring - Part 1

People who are used to the UK system of wiring power outlets often find the French method of installing sockets a bit strange. It is, however, simpler & more logical than the unbiquitous ring main......

A principle difference is the French technique of having specific circuits & sockets for major appliances. So, there is an individual circuit breaker in the consumer unit for the washing machine, another for the dish-washer, another for a tumble dryer (there are others, but more of that another time). Each of these circuits consist of live(phase), neutral (neutre) & earth (terre) wired in 2.5mm² cable, & are supplied via a maximum 20 amp circuit breaker. The circuit terminates as a single socket outlet next to/behind the appliance. As in the UK, there is also a dedicated circuit for a cooker, rated at 32 amp, wired in 6mm² cable (this can be terminated with a 32 amp socket, or a simple cable outlet).

Shifting such major loads onto their own circuits means that the circuits supplying other sockets don't need the capacity that a UK ring main can supply. French sockets (prise de courant) are wired in a radial or "daisy chain" format i.e. the supply goes in & out of a run of sockets, then ends. There is no return back to the source of supply, as happens in a ring main.

More about general purpose sockets another time....

TNT/Freeview update

I've updated the information written on 24/01/2008 regarding using UK Freeview boxes to receive the French digital TV service, TNT.

It turns out that my sweeping statement about being able to use a UK Freeview box in France wasn't wholly correct & that there are some that won't do the business over here. Please go the the post entitled "Will my old TV work in France?" to see the correct version.