G-J-B

In the downstairs bathroom there is a rather old light socket. I've replaced lights before, but there is an additional two wires that powers a ventilation fan. I'm a little confused because black and red indicates live, and blue neutral, and yet there are two black wires going into one connector and the red and the blue in the other. I can wire it up in the same fashion, but wondered if anyone with more knowledge could tell me why this is?

Thanks in advance.

dmu

Hi, I haven't the faintest idea, but welcome back to the forum!!

G-J-B

Hi 'DMU', I remember you, hope all is well ! Yes, it's been about six years or so, I tend not to frequent the forums very often.

south_bound

I had understood that blue is neutral and other colours are live (plus green/yellow for earth of course), though older rules were different. My house has all sorts of colours such as green, purple, brown and each of them seems to have been used as live or neutral in some place or other so either it spans old and new rules or not all electricians follow the right standards. At the end of the day, as long as you use the right cable size for the application, the electricity doesn't care what colour the insulation is but the next person to make a modification will, so it is worth getting it right if you can.

G-J-B

These old houses are a nightmare, especially for this sort of thing. At least if you find colours from an older installation, you can determine what they were historically, but when the colours aren't respected it's more problematic. I've only installed the odd light over the years and a couple of light switches. It's all been straightforward so far. I don't really want to pay the call out/installation fees for an electrician to install an inexpensive light using existing wiring.

This is the lamp I'm looking to install, it came with wire screw caps. I've got an AC detector and neon screwdriver, but I think I will have to buy a new volt meter (lost my old one) and ensure which are definitely the live and which the neutral, and then wire them up with the two black together and the blue and red together as before. If I hadn't seen it wired that way, I would have never put the blue and red together!

bjgironde

They did use all sorts of colours for the wiring although normally black or red are used for live feeds, but I never take anything at face value and always check with a meter. You don't say what colours are connected to the ventilation fan, however, if you look at the fan connections, you should see that you have a simple parallel feed to it, using the switched live from the light fitting and its neutral regardless of the colours they used. When I find the 'wrong' colour used for live or neutral, I normally wrap a piece of appropriately coloured insulating rape round the wire where it connects, as an indicator for anyone in the future.

G-J-B

I haven't attempt to remove the ventilation fan to see what wires are connected to it. There isn't much slack in the cables, and I haven't removed the old socket yet. I thought I'd order one of those contactless voltage testers to confirm the live and neutral, and then I'll wire it up with the two black together and the blue and red together as before. I'm sure a neon screwdriver is fine, but I don't really want to be part of the circuit that tests it.

The tape is a good idea. I did actually order and received some different coloured electrical tape with the plan of doing just that.

Chatter Static

You need to replace the current light fitting with "Boîte d'encastrement DCL" "and here" with or without the hook the reasoning behind the new style box is that if and when you move and decide to take the light fittings then bare wires are not left.

They come with a Bayonet for light bulbs which you tend to see bare in most newer French houses these day and a little plug which is designed to go on the new fitting you have. "As shown HERE"

Is the light fitting served by two switches i.e. two-way "interrupteur d'éclairage bidirectional" I believe the blue is used as the slave line in France they are in our house but we have one light fitting with five switches four of them can be reached by walking less than three steps.

Le Grand also sell a book that explains a lot of the basic stuff which can be worth buying I know Leroy Merlin stock it in most stores.

Or having reread your post the extra wire could be a feed to the fan, If you don't have one invest in a electrical tester it can help diagnose issues like this.

Purple Jim

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