Wiring an extraction fan

[oliverpenney]

So, I am finding it very difficult to add a fan to my bathroom. Installation is easy, but the wiring has blown me. Not literally.

Basically, I have a standard pull cord for a light, by the door with 3 core wire going to it from the light around 2m away. The light has 2 live, 2 neutral and 2 earths from other lights going to it (as well as one other of each to the switch).

The fan I have have space for a live and neutral wire. How do I go about wiring it so that the fan goes on when the light is switched on.

I have used a junction box with 3 terminals and linked into it, the switch, the fan and the power from the light.

It works but the fan turns on when the light is off. How do I change it around? I am very confused. Thanks

 

[EFLImpudence]

Does the fan have a timer?

 

[17thman]

I doubt the fan has a timer if it only has a L and N connection.

 

[17thman]

when you say the fan turns on when the light is off, do you mean that it remains on when the light is off?. If so you have connected the fan Line to permanent Line, not the switch Line

 

[EFLImpudence]

I doubt the fan has a timer if it only has a L and N connection.

True - missed that.

 

[nickjb]

There's a guide in the wiki that might help:
http://www.diynot.com/wiki/electrics:lighting:fan?s[]=fan

 

[oliverpenney]

When the light is turned on, the fan turns off, and vice versa.

So when the light isn't on, the fan runs all the time. Any suggestions?

And it has no timer.

 

[bernardgreen]

Most probably you have connected the fan's Live and Neutral to the Live and Switched Live in the cable going to the switch.


When the switch is OFF the fan is getting power via the lamp ( you might notice it clowing very dimly ). In this state the fan's Live is connected to the live wire to the switch which is live. The fans neutral is connectied via switched live and the lamp's filament to neutral. Not a perfect neutral but enough to supply a fan motor

When the switch is ON the Live and Switched Live are connected in the switch so both are Live so the fan has two lives and no neutral.

 

[oliverpenney]

So how do I wire it, from the light or the switch?

 

[ban-all-sheds]

Any suggestions?

There's a guide in the wiki that might help:
http://www.diynot.com/wiki/electrics:lighting:fan?s[]=fan

My suggestion is that you read it.

 

[ban-all-sheds]

So how do I wire it, from the light or the switch?

How can you wire it from the switch? Where would you get the neutral?

http://www.diynot.com/wiki/electrics:fan?s[]=fan

 

[bernardgreen]

So how do I wire it, from the light or the switch?

You wire it to the same terminals as the two wires from the lamp. Then when the lamp has power switched on the fan also has power to it.