Wiring an Immersion Heater Timer

[Nathan]

I've got a digital immersion heater timer I want to install, but it's not clear from the instructions how to wire it in. Others I've seen have been very simple - supply here and appliance here. But this one is much more confusing.

It has 5 terminals labeled: L N COM NO NC

I have Live, Neutral and Earth coming from my supply and Live, Neutral and Earth from the immersion heater (which runs about 3kW).

The wiring diagram for the timer seems to show that I need to connect the L and COM terminals to the live supply. Connect the neutral supply to the N terminal. And connect the heater to the NO termincal and to the neutral supply.

In other words, I think the device itself is powered via the L and N terminals, and when it switches it connected COM to NO. That's how it seems to me but nothing in the instructions is very clear.

So, anyone have any ideas how I can connect this? Is it OK to jam the two neutrals into one terminal to connect them?

The timer is a CED Control Master General Purpose Timer. Model IMT7E

Many thanks,

n

[BigWallop]

Your Live is connected to the "L" connection along with a jumper link, of the size cable, to the "COM" terminal.

Your neutrals, both of them, are placed together in the "N" connection.

The live supply to the heater element is taken from the "NO" (normally open) connection.

The "NC" (normally closed) connection doesn't need to be used.

The earth connections should be taken to a separate terminal block connector if there is no provision for it inside the new timer unit..

[Crooksie]

hi there not familar with this unit, check to see if its rated for the appropiate loading, i.e 3kW, or 15Amps or more. connections L - Live wire in, and COM, brown (its ok to connect two wires to the same terminal) N - Neatral wire in, Neatral wire out to heater, both blue COMM - link wire (brown) to live using a short piece of same type wire NO - Live wire out to heater, brown NC- Not connected Not forgeting to reconnect the earths if they have been broken. SAFETY ! Dont forget to swich off the mains Regards bob

[Dave Plowman]

COM, NO and NC refer to the switch part which is totally independent from the mains supply - so you could use it for say low voltage work.

COM is common - the feed into the switch

NO is normally open, so the one you'd use to switch the load *on* when it operates, ie the way you want.

NC is normally closed, so you'd use this to switch the load off, and you can ignore this.

[Nathan]

Thanks everyone - fitted it as above and it works perfectly. It's 16A rated so it should be safe.

ta,

n