Socket spurs?

[briwy]

We are about to complete the purchase of a property in the Pyrenees and will want to fit more sockets.

I have done a fair ammount of wiring in the UK so am OK with the

mechanics of it but just want to make sure that I do things properly in

France.

I am aware the the the wiring to sockets is a radial circuit and that

as far as I can see up to eight sockets are normall allowable depending

on the circuit rating.

If there are not this many sockets on the circuit is it allowable to

take spurs off  (as in the UK) or do any extra sockets have to

come from the last existing socket.

Is DIY wiring actually allowed in France or is it like the UK where it can now only be done professionally?

Thanks for any help

Brian

[La Guerriere]

You can do-it-yourself. Eight sockets max on a single circuit 2.5mm2 cable with a 20A disjoncteir at teh board, and I beleive you can just add-on spurs as necessary connecting at a socket. Oh, and those eight can be single or double sockets, a double counts as a single in the adding-up.

[briwy]

Thanks la guerriere

Thats great,  thanks for the info

Brian

[Alcazar]

I'm sorry to disagree, but I believe that you CAN'T make connections at an existing socket, only at a "boite de derivation" or junction box.

That's certainly how it's shown in my books, and how I've done it in my barn area, which is the only bit I've rewired so far as regards sockets.

I wait to be corrected by one of the real experts on here...........

Alcazar

[Cassis]

I'm not a real expert.  My French DIY manual says extra sockets should be taken from a boîte de derivation wherever possible.  But in older houses it says this may not be possible as the wires and any boxes may be all inside the wall - no visible boîte.  In this case it says you can take off an existing socket.  But you can only do this if:

1. the existing socket is fed by 2.5mm wiring,

2. the circuit to which it belongs has 5 or fewer existing sockets on it,

3. you use 1.5mm wire for your new socket wiring and

4. you do not exceed the circuit protection rating.

I repeat - I am not an expert - I am just translating what it says in the book!

[Nick Trollope]

Alcazar is right is this case (sorry if this is misinterperated...!!!)

Ie. You cannot put 3 sets of wires into a socket. You must find & interrupt the cable & add a boite de derivation - which must be accesible once the connections are made - and T off from there, or find the last socket and daisy-chain from there.

Max 8 sockets on a 2.5mm2 circuit (could be 8 doubles, though) max 5 on 1.5mm2 circuit (or a circuit which is a mixture - happens, you know).

 

[tj]

 

Could we just clarify one point, true or false ? that there is no legal requirement for any "boites de derivation" thus, all sockets can be run "daisy chained" from the board.

thanks

 

[La Guerriere]

I stand corrected.

Mind you I don't think you can actually get more than 2 x 2.5mm2 into a standard terminal, they are just too weeny.

 

[Nick Trollope]

[quote user="tj"]

 

Could we just clarify one point, true or false ? that there is no legal requirement for any "boites de derivation" thus, all sockets can be run "daisy chained" from the board.

thanks

 

[/quote]

True!

[Dave&Olive]

hi

              ok no expert myself  but what I have gleened from the " book " is :-

         uk cable is a no...no!!!

         5 sockets with 1.5 mm cable with a 10 amp fuse or 16 amp disjoncteur , run in 16 size gain  3 cables max

         8 sockets with 2.5 mm cable with a 16 amp fuse or 20 amp disjoncteur , run in 20 size gain 3 cables max

           double sockets count as 1 , 3 +4 sockets count as 2

               spurs are a no no big time

           this means if you say you want to go left and right from a socket you have to put in a box because you can only have 2 set of cables in the back of a socket

          if I am wrong I will be only too happy for someone to put me right, and would feel safer if someone does

                    dave

oh and ps you must be able to rewire it without pulling the house down

[Loiseau]

[quote user="La Guerriere"]... those eight can be single or double sockets....[/quote]

 

Double sockets!!  Can you really get those in France?

 

Angela

 

[powerdesal]

Angela,

Yes you can, and triples, never seen a quad back box but certain types

of back box clip together to form the double, triple or quad., after

the individual prise is in each place the face plate fits over the lot.

Sorry if its not clear but I know what I mean !!!!!

Usual caveat, if someone knows more or better then I stand corrected as

this is only my personal view and should not be taken as 'gospel'

Regards

[briwy]

Thanks for the help everyone.

Brian

[Gluestick]

 A couple of points to remember, here.

When sockets are "Daisy Chained", ALL of the total load, is carried by the first socket, in the chain, since the sockets are acting as distribution terminals as well as end-feed sockets.

Thus, if you have eight doubles and say the theoretical load is 2,000 Watts per socket, (fan heaters e.g.) then the first is expected to carry 7 X 8.69 Amps = 69.56 Amps!

Additionally, since the French mains is a Voltage driven system (unlike the UK where it is a Power -  i.e. current driven system), the voltage can significantly reduce at each successive socket in the chain.

Therefore often far better to split the chain into two separate circuits.

I know that the scenario above is pretty far out, but once sockets are installed, the load capacity is often forgotten, as users gaily plug in all sorts of kit with abandon.

 

[Gyn_Paul]

[quote user="Gluestick"]

 A couple of points to remember, here.

When sockets are "Daisy Chained", ALL of the total load, is carried by the first socket, in the chain, since the sockets are acting as distribution terminals as well as end-feed sockets.

Thus, if you have eight doubles and say the theoretical load is 2,000 Watts per socket, (fan heaters e.g.) then the first is expected to carry 7 X 8.69 Amps = 69.56 Amps!

Additionally, since the French mains is a Voltage driven system (unlike the UK where it is a Power -  i.e. current driven system), the voltage can significantly reduce at each successive socket in the chain.

Therefore often far better to split the chain into two separate circuits.

I know that the scenario above is pretty far out, but once sockets are installed, the load capacity is often forgotten, as users gaily plug in all sorts of kit with abandon.

 

[/quote]

Yes but exactly the same could be said of the terminals in a boite de derivation !

At every stage along the way you have a pair of cut wires gripped together  by a screw terminal  (in the back of a socket), or THREE wires in a choc-block connector or THREE wires in a borne , in a  boite.  the only difference I can see is that the connector in the boite is getting warm inside the wall !

Also can you explain please what you mean by "Voltage driven" v "current driven" , 'cos I don't understand this bit of the argument

thanks

p

[Nick Trollope]

[quote user="Gyn_Paul"]
Also can you explain please what you mean by "Voltage driven" v "current driven" , 'cos I don't understand this bit of the argument

thanks

p
[/quote]

No, neither do I.

The only difference between a "daisy chain" and "ring" circuit is the effective x-sectional area of the wire used. In both cases we use 2.5mm2 cable, but in the UK the effective area is 5mm2, because the cable feeds back to the MCB. I don't propose to start another debate on UK v Fr wiring, other than to say that the UK is in a pretty exclusive wiring methods club.

You can't have (electrical) power without voltage or current. It makes no difference whether the current flows along a piece of wire connected at one or both ends (being AC, it doesn't actually flow in one "direction" anyway). It is only the resistance of the cable that is significant. Resistance (in a cable) = heat. However, more resistance (and hence heat) is likely to be generated in the connections than in the cable (which is insignificant for modern copper cable). Hence the limited number of sockets in the French system - a UK ring main could have a whole floors' worth of sockets - Fr limited (typically) to 1 room. To stop people plugging in 8 x 2Kw heaters we fit 20A breakers in each circuit.

Oh, BTW, boite de derivation cannot (as discussed plenty of times) be hidden in a wall. Typically, they are more accessible than a socket, if installed correctly, which is why they are used!

 

[powerdesal]

I also dont understand the 'voltage driven vs current driven' comment.

Question: Whilst the normal French way of boite de derivation (junction box) is a plain box with choc bloc connectors in it ( x 3 ) is there any reason why a standard UK style 4 post screw lid JB cant be used?

The reason I ask is simply that I hate chocolate block connectors, no real reason, I just do.

I realise of course that you dont actually need 4 posts but thats how they come. If you are a real smooth spark I suppose you could strip the insulation off without cutting the wire and then only have two wires in the post which must be good for limiting the I sqrd R losses.

Next Question: does a JB behind skirting board count as being 'buried' its accessible by removing the skirting board securing screws ?

Regards

[Cassis]

I can't see any junction boxes at all in our house.  It was rewired in the late 80's.  Should I be worried?

[powerdesal]

Cassis,

Difficult to answer, maybe all your circuits are 'daisy chained' or then again..............!!!!!!

Regards

[La Guerriere]

And anyway, it will click out at 20 Amps at the MCB (unless you've put the nail in an old fuse carrier)

[powerdesal]

You mean the traditional 'fuse-bolt'

[Cassis]

Should the silver paper in the fuse box be replaced regularly?[;-)]

The electricians who did our upstairs conversion did not suck their teeth and tut-tut or offer a quote to rewire the house, and they had to mess with the existing wiring and fuse box, so I'm guessing that what is there is okay despite the lack of junction boxes.  Yes?

[powerdesal]

Only when its fully melted.

On a more serious note (how sad on Saturday night to be posting here!), do you actually have a fuse box or is it a modern Tableau d'electricite with disjonctuers? How many new sockets did they install and did they need to fit additional disjoncteurs or did they extend existing circuits? Its v.difficile to analyse from 4000+ miles  [:)]

Regards

[Cassis]

I have to go out now - taking a party of half-mad guests up to the restaurant (chaperoning).  Can I PM you tomorrow, if it's not too much trouble?  I can post you a photo of the old and new boxes.  They put a complete new box in upstairs.  They are part of a big company and were supervised by the architect so I'm confident they did a good job.

[powerdesal]

No problem, I'm going to bed now anyway,

Regards