Wiring colours in uk

[Jazz carne]

I am Uk based: I have brown, blue and black wire on the extractor fan. From the power source I have brown, grey and black wires... please how I connect them to the extractor. All help be great.. thank you

 

[Lister1987]

Take some pictures and it'll help get an answer.

 

[telectrix]

first, is it a timer fan? if so, you need to know which conductor does what. you will have a perm. L, (from isolator) switched L (when the light comes on), and neutral.

 

[Jazz carne]

first, is it a timer fan? if so, you need to know which conductor does what. you will have a perm. L, (from isolator) switched L (when the light comes on), and neutral.

It’s linked to the lights....

 

[Mike Johnson]

Where are you looking for the power source, they should be Brown (phase) Blue (neutral) and Green/Yellow (Earth) as you have Brown wire's I assume this is not a very old installation as the phase is in harmonised colours. Any further information needs more information.

 

[snowhead]

Is this replacing a fan that was already connected?

 

[Jazz carne]

Where are you looking for the power source, they should be Brown (phase) Blue (neutral) and Green/Yellow (Earth) as you have Brown wire's I assume this is not a very old installation as the phase is in harmonised colours. Any further information needs more information.

The painter took the fan off and all I want is to connect back up...but I am not sure how the wiring goes.. please advise

Is this replacing a fan that was already connected?

No same fan ... the painter took it off and I do not know the wiring combination
[automerge]1585324143[/automerge]

The painter took the fan off and all I want is to connect back up...but I am not sure how the wiring goes.. please advise

No same fan ... the painter took it off and I do not know the wiring combination

 

[Mike Johnson]

Is there an isolator switch in the room?
How are the lights controlled, wall switch or pull cord?

 

[pc1966]

Sadly there are no set rules for this. Most likely your fan has brown = live, blue = neutral (harmonised = current British colour code) and by elimination black is probably the switched live (i.e. from the light).

At a guess the cable would be brown = live (because that is the harmonised colour for live), black = neutral (because that was the old British colour for neutral) and so probably grey = switched.

But you really need to check carefully as the person who wired it might think differently from me! If in doubt get a sparky in to check, don't try to test a live system yourself.

In case you wonder why the wire has those colours, the colour code for a 3-phase system has:

• Live 1 = brown (old = red)
• Live 2 = black (old = yellow)
• Live 3 = grey (old = blue)
• Neutral = blue (old = black)
• Earth = green/yellow (old = green)

While it is very rare to see 3-phase supplied for a domestic property, it is common to need 3 wires & earth for two-way switches (and for fans like yours) so usually the 3-phase colours end up being (ab)used in that job.

 

[telectrix]

more likely brown L to brown. Black switched L to Black , Grey(should have a blue sleeve) N to Blue. if the brown and black are reversed, the fan won't operate so switch them round. failing which, get a local sparks to ID the cores and reconnect.

 

[pc1966]

Grey(should have a blue sleeve) N to Blue.

If only folk would mark things properly!

 

[Mike Johnson]

If only?

The Switched live should change colour at your lighting switch?

 

[freddo]

You would need to test/visually verify the other end of the cable. As it is still common to see people using a black wire in a harmonised coloured cable as neutral, even though they shouldn't.

 

[pc1966]

As it is still common to see people using a black wire in a harmonised coloured cable as neutral, even though they shouldn't.

The question is, which should they use?

Grey - that is another phase colour!

Now if only there were a standards organisation that could specify this...

 

[Risteard]

The question is, which should they use?

Grey - that is another phase colour!

Now if only there were a standards organisation that could specify this...

Just mark it (e.g. with sleeving) and there's no issue.

 

[westward10]

The question is, which should they use?

Grey - that is another phase colour!

Now if only there were a standards organisation that could specify this...

Grey is a line colour unless it is identified otherwise. Neutral can any of the colours under the sun provided it is sleeved/marked with blue.

 

[davesparks]

The question is, which should they use?

Grey - that is another phase colour!

Now if only there were a standards organisation that could specify this...

Traditionally core numbers 1 and 2 were used for lives and core number 3 was always used for neutral in this kind of arrangement.
1 being brown (red)
2 being black (yellow)
3 being grey (blue)

So the blue was always used as neutral therefore the logical choice is grey for neutral.

 

[pc1966]

Traditionally core numbers 1 and 2 were used for lives and core number 3 was always used for neutral in this kind of arrangement.
1 being brown (red)
2 being black (yellow)
3 being grey (blue)

So the blue was always used as neutral therefore the logical choice is grey for neutral.

Good point, as it puts the earth between the live pair and the neutral which would lead to better RCD protection against insulation breakdown.

Does anyone know if this is documented in IET docs or in training, etc?

 

[davesparks]

Good point, as it puts the earth between the live pair and the neutral which would lead to better RCD protection against insulation breakdown.

Does anyone know if this is documented in IET docs or in training, etc?

That sounds like nonsense to me, trying to create a technical reason for something where there isn't one. That would only apply to T&E anyway.

No it isn't documented in any IET documents as there is no formal requirement either way, as long as cables are properly marked it will comply.