Correct colour code for switched-live

[ericmark]

In a single phase installation are Line (Phase) wires should be Brown and all Neutral wires should be Blue if colour system is used. With green and yellow for earth.

And if I'm using this scheme, what colour should switched-live be? If I have to sleeve it, what colour should the sleeve be? I've seen yellow, brown, black and grey mentioned. It seems odd that such a common function as switched live should not have a standard colour. Sleeving it brown (which I've seen suggested) seems very unhelpful, and provides no way of distinguishing between the live feed to the switch, which should always be live, and the output from the switch, which will sometimes be live, and sometimes not (so voltage-wise it will be picking up neutral through the load). Using black seems a bad idea to someone who remembers the old cable with black for neutral.

Thanks - Rowan

It has a standard colour "Brown" you can also use numbers and/or letters to identify. In the same way as continental cars ID their wires 31 earth 30 live etc. The idea of having a full colour code like British cars green/purple indicators supply may seem OK until you realise the same regulations are used in industry when most of the cables are switched in some way and there are just not enough colours. So normally cables are numbered and boot lace ferrules are used to ensure they don't fall off. However this would increase the cost and so in domestic it is considered with just 4 live wires in a ceiling rose it does not need any OTT ID system.

Colours are used to ID different voltages and when one opens a typical control panel you will see purple, white, red cables which show they are 24V, 110V, 220V control circuits. I am sure manufactures could produce brown cables with trace colours but to get firms to use twin and earth with two brown cores in the main has failed because of extra cost so what do you think are the chances of getting anyone to buy cable with trace colours?

Answers from 1 to 0% please. House wiring is very simple. It is not rocket science and if one can't work out which of 4 wire is which well you should leave well alone.

 

[plugwash]

In general what I would do with switched lives etc is put on a small peice of brown sleeving therefore marking it as a live but leaving the underlying core colour visible so you can easilly tell which conductor is which.

 

[Taylortwocities]

The plan put forward for harmonised colours in multi-cored cables was to use brown as live and grey as neutral.

The reason put forward was to drive folk away from using the old "black is neutral" paradigm.

All of the new v old diagrams show this. eg http://www.tlc-direct.co.uk/Technical/DataSheets/Cable/CableColoursLeaflet.pdf

There is absolutely nothing to stop you using black as neutral but it should be sleeved blue to comply.
If you have a switched live conductor it must be sleeved brown to show that it is, or can become, live (line/phase for the purists).

 

[rowanbradley]

Thanks to everyone who has contributed to this thread. I now think I know what to do, and what I must not do!

Thanks - Rowan