extractor fans for dummies

[redz83]

feel like a fool but i unwired an extractor fan to put some pannelling on behind it and forgot to note what wires went where, fool.

i've uploaded an image of what the connection looks like unconnected, is there an way of telling what should go where without reference to the instructions?
//www.diynot.com/network/redz83/albums/

 

[sparkyspike]

Not really! Are there any markings next to the terminal block (such as L, LS N etc).?

The trouble is, no one knows how the original electrician wired it up. He could have used red as permanent live or as switched live. There's a 94% chance that the blue cable is being used as a neutral and goes in the terminal which already has another blue cable in it. Then the red and yellow will go in the other two unused terminals. If the fan doesn't behave normally, then swap red and yellow.

BUT, if blue isn't neutral, you could damage something, so if you have a multimeter, use it to test which cable is neutral. Or look in the fan isolator switch to see where the blue cable goes.

 

[redz83]

thanks for the reply, will give it a shot, the fan could probably do with being upgraded anyway
unfortunately no markings next to block

 

[sparkyspike]

Obviously not in a hurry then!