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Thread ID: 113509 2010-10-23 01:00:00 Wiring a light switch jwil1 (65) PC World Chat
Post ID Timestamp Content User
1147028 2010-10-23 01:00:00 Hi

I'm installing a light in a cupboard and want to use a door switch (one that switches the light off when you close the door). I'm using a HPM switch from Mitre 10.

I'm a bit confused as to how to connect it up. The switch has 3 terminals, labelled COM, NO and NC. The switch will sit in between the power source and the bulb.

Which wires do I connect up to where??

Thanks
jwil1 (65)
1147029 2010-10-23 01:04:00 COM = Common - one wire goes here
NO = Normally open
NC = Normally closed

Since you want the switch to be 'open' or off when the door is closed and 'activating' the switch, you'll want the other wire to go to the NC - normally closed.
SoniKalien (792)
1147030 2010-10-23 01:10:00 Just remind me - which is active which is neutral - blue or brown? Do the 2 neutrals go on the same terminal?? jwil1 (65)
1147031 2010-10-23 01:11:00 Brown or red is active, blue or black is neutral. There should only be one neutral wire in a cable; the third wire (green or green / yellow) is earth, and under normal circumstances should never be linked to the same contact as any of the other wires.

Edit: It's possible we're talking about two different things - what you've described sounds like a single-pole switch, which would normally be attached to the active wire only. The earth is often (but not always - depends on the switch type) connected to the switch housing, and the neutral gets passed through directly without touching the switch at all.
Erayd (23)
1147032 2010-10-23 01:20:00 This is a switch though - so there are two earths, neutrals and actives... jwil1 (65)
1147033 2010-10-23 01:24:00 This is a switch though - so there are two earths, neutrals and actives...Oh gotcha - you're referring to the cut ends.

The switch should be wired like this:

---N-----------------------------------------Light Socket

---A-------COM NC--------------------Light Socket

---E-----------HOUSING-----------------------Light socket

The NO terminal should be attached to nothing at all.

If this doesn't achieve what you want (i.e. turns the light off when you open the door) - you may need to use the NO terminal instead, and leave the NC one empty.
Erayd (23)
1147034 2010-10-23 03:32:00 Thanks guys, got it working :) jwil1 (65)
1147035 2010-10-23 03:45:00 Hi jw*
Bear in mind that in case of fire caused by your wiring your insurance company will throw a hissy-fit.
Scouse (83)
1147036 2010-10-23 04:21:00 Got it working
Do you really want to risk the lives of your family?
Make sure that your work is inspected by a registered electrician before you switch in on. (That is the law in this country.)
The fact that it seems to work will carry no weight with the Fire Service or your insurance company in the event of problems, not to mention the risk of prosecution. :horrified
coldot (6847)
1147037 2010-10-23 04:25:00 Yeah I've wired up switches before and I'm by no means qualified or even competent but I'm not really sure you should be even trying to put up a fence based on your post history mate.

No offence, you just don't seem all that onto it.
roddy_boy (4115)
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