The Grey Wire?

[lawrie29]

SO, I have disconnected the extractor fan from the light switch as I was getting fed up with it kicking in and sucking out all the hot air from the half converted garage. So I have removed the cable going to the fan from the switch, and am left with the four core cable form the light.

I have -
Earth,
Brown - LIve?
Black - Neutral? - going to L1?
Grey - WTF? - where has this come from? go to?

I just want to wire in the switch, which is just a standard unit.

I have swapped switches and sockets over many times, but a Grey cable?

I appreciate to those in the trade, its a daft question, but I am assuming it is to do with the extractor which would run on for a period after the light was turned off.

Appreciate your help.
Ta.

 

[sparkyspike]

Grey is normally neutral, black switched live and brown live (used for a fan run-on or for a downstream circuit), but to be honest, could be anything... Neutrals and lives are normally marked with blue and brown sleeving. If they're not marked, then you need to trace the other end of the cable and if necessary do a continuity test to determine which is which!

 

[lawrie29]

It was nly installed less than 10 months ago, and by a pro, so can I assume what you say is correct? And also If I did get it wrong, what is the worst that can happen - blow a fuse?

 

[lawrie29]

I have checked the wiring going into the fan, which is now not connected to anything. Grey is Neutral, Brown is S/l and Black L.

So how will this translate back to my switch?

I should have written down what went wear before disconnecting, but I remember some cable twisted togther - blacks and browns to each other, with the grey going into a connector block. Would that make sense?

 

[sparkyspike]

and by a pro

Not a pro, if the cores are not sleeved!

Anyway, I'm a bit confused by what you say you have done. Have you a 3C and earth cable running from the switch to the fan and a separate 3C+E running to the light? What other cables are in the switchbox? A 2C+E brown and blue?

 

[david_uk]

When we wire in a bathroom fan, we take a three core cable from the light fitting to the 3 pole fan isolator with live, switched live, neutral and earth, leaving the light switch connected as normal. The fan should have been wired similarly to allow for isolation of the fan for servicing. So to turn off the fan, all you should have needed to do was turn of the isolator and the light should work as normal. Has it not been wired this way? Was it necessary to start disconnecting wiring to turn the fan off?

 

[lawrie29]

there was no seperate isolator for the fan. If there had been, it would have made the job easier, would have just flicked the switch.

The fan was wired in on a timer to stay on a while after the light was turned off. Essentially this was hard wired in, the only way to service the fan would be to turn off the power.

Would this explain the browns and blacks twisted together L and S/L linked what does that do? Or would it be that he has not used the same colours for the different sides of the switch?

 

[sparkyspike]

You need to be a bit clearer as to what is in the lightswitch. There are several ways it can be wired up. The most likely is a fed switch, with live (brown) into COM and neutral (blue) into a terminal block. L1 will provide the switched live to your light. The fan wires are then connected thus: L (black) = COM, SL (brown)= L1, N (grey) = neutral terminal block with the blue wires. This would give you a black and brown in one terminal as you say.

 

[lawrie29]

Lets forget about the fan, I don't want it wired up anyway, and ahving taked the cover off to see what wires went where has let me see a bit of scorched flex, so decommisioning this.

The pendant fitting has 2 sets of cables going into it. the 3 core+earth and a 2 core +earth. THe pendant has a blue and a brown.

The blue from the 2 core and the grey are together, going the the blue of the pendant

The browns from both the 2 core and the 3 core are joined

the Black from the 3 core is joined to the brown of the pendant.

THis shed any light (and I need to shed light, it's going dark)

 

[sparkyspike]

Yes it does.

 

[lawrie29]

Thanks SParky Spark, could you shed this light in my direction?

 

[sparkyspike]

The 3-core goes from the pendant to the light switch. The grey is the neutral which goes into a neutral block (used for the fan). The brown goes to COM and the black goes to L1. When you reconnect the fan, wire in the grey to the neutral block, the brown to L1 and the black to COM.

__________________

 

[sparkyspike]

And don't forget to sleeve the cables to identify live and neutral.

 

[lawrie29]

THanks for your help, however, not looking to rewire in the fan. What goes where to get the light to work again?

 

[sparkyspike]

The 3-core goes from the pendant to the light switch. The grey is the neutral which goes into a neutral block (won't be used). The brown goes to COM and the black goes to L1.

Terminate the 3 fan wires at the switch, with small terminal blocks, or pull it out completely.