Immersion Heater Timer Switch

[keithlbw]

HELP
I've just bought a timer switch for my immersion heater.The instructions say connect the live from the SUPPLY to terminal 2 and the live from the HEATER to terminal 1 . Neutral wire is not a problem as both go to terminal 3. Earth is not a problem either.

When I take my old on/off switch off the wall how do I know which live is supply and which is to the heater.

Also posted in Home and Garden under DIY.

[dipee65]

I presume the switch is remote from the immersion heater, so you can't simply tell by visual inspection which is which.
The live incoming supply wire should go to a terminal marked "Live" or L1. Another clue is if there's an neon indicator on the old switch then its wires will go into the OUT side of the switch.

[keithlbw]

Have you been looking behind my switches Alan.

Your answer was spot on.
Thanks a million for a quick answer.

Regards Keith.

[buildersmate]

They're all wired like that.