Replacing Shower Fan Isolator Switch

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ywu_

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I have an existing isolator that allows the fan to come on when the light is switched on. It needs to be replaced and have bought a new switch already but I've found that the labels on the back for the wires are slightly different. Can anyone help with which wires go where on this setup please?

OLD: L1, L2, N1, N2
NEW: L1(IN), L1(OUT), L2 (IN), L2 (OUT), N (IN), N (OUT)

All the wires are red.

Many thanks!
 
Your old switch is double pole, the new one is three pole.
If you have a timer fan (ie runs on when the light is switched off) then you should have six wires in your switch. Live, neutral and switched live. Do you?
If you have only two pairs of wires then

L1 = L1 in
L2 = L1 out
N1 - N in
N2 = N out
 
I only have four wires (all red) plus the earth but the fan does stay on for a few mins after the light is off. There are a couple of black wires currently joined with a terminal block.
 
OLD: L1, L2, N1, N2
NEW: L1(IN), L1(OUT), L2 (IN), L2 (OUT), N (IN), N (OUT)

All the wires are red.
Click to expand...

Old L1 - New L1 (In)
Old L2 - New L1 (Out)
Old N1 - New L2 (In)
Old N2 - New L2 (Out)

There are other permutations which would be fine as well. Are all the four wires really completely red, or are a couple of them yellow or blue with red sleeving?

The black neutrals currently connected together can also be separated and connected into the new N (In) & N (Out) terminals, assuming that the neutral through the box is going only to the fan and not feeding the light as well.
 
Actually, I've just checked, the old N1 and N2s are yellow with red sleeves.
 
Sounds like you have a DP switch acting on the L and SL but the neutrals bypass the switch.
 
yes, they are. I assume that doesn't change anything?
 
ywu_ said:
yes, they are. I assume that doesn't change anything?
Click to expand...
No - Connect red, red (yellow) and black (blue) from one cable to L1, L2 & N (In) respectively on the new switch, and the matching colors from the other cable to the corresponding L1, L2 & N (out) terminals.
 
Get the IN & OUT the right way round - saves confusion later on and it's a proper job. Unlikely the TP fan switch has a neon.

You will need a multimeter.
 
Sorry to be dumb but what reading should I expect on the IN or OUT?
 
ywu_ said:
Sorry to be dumb but what reading should I expect on the IN or OUT?
Click to expand...
I guess you're not too worried now that it's all done, but the readings would be on the existing cables to determine which is bringing power to the switch and which is the cable going on to the fan. As suggested, it might be nice to make sure the former is connected to the terminals identified for "In" and the latter to those marked as "Out," but it in no way affects either operation or safety if you connect them the opposite way around.
 
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