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jwil1
23-10-2010, 02:00 PM
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

SoniKalien
23-10-2010, 02:04 PM
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.

jwil1
23-10-2010, 02:10 PM
Just remind me - which is active which is neutral - blue or brown? Do the 2 neutrals go on the same terminal??

Erayd
23-10-2010, 02:11 PM
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.

jwil1
23-10-2010, 02:20 PM
This is a switch though - so there are two earths, neutrals and actives...

Erayd
23-10-2010, 02:24 PM
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.

jwil1
23-10-2010, 04:32 PM
Thanks guys, got it working :)

Scouse
23-10-2010, 04:45 PM
Hi jw*
Bear in mind that in case of fire caused by your wiring your insurance company will throw a hissy-fit.

coldot
23-10-2010, 05:21 PM
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

roddy_boy
23-10-2010, 05:25 PM
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.

ubergeek85
24-10-2010, 06:16 PM
I'm with coldot here. Ring a sparky.

Doesn't cost much, they just come out, check your job, if it's up to spec (IE the same level that they'd do it to), then they'll sign for it.

Really, do you want to risk everything for less than a hundred bucks? The rules are in place for a reason. Sure the wiring is simple, but the fact that it hasn't been signed for (and proven safe) is a serious problem.

tut
24-10-2010, 06:19 PM
If you have a brown wire in there you are using the wrong cable.

roddy_boy
24-10-2010, 07:15 PM
I'm pretty sure you are allowed to do your own wiring like this so legally he's all good and doesn't need it signed off. Insurance might be a different story though.

ubergeek85
24-10-2010, 07:18 PM
IIRC, it depends how it's connected to the mains supply (socket vs. hard-wired).

roddy_boy
24-10-2010, 07:23 PM
Yeah looks like you're right actually.


What can you do?

# Installing, extending, or altering any cables (except the main cables that come from the street to your switchboard). You have to get the finished job checked and tested by a licensed electrical inspector. You cannot connect your work to the electricity supply yourself. The inspector will connect it, test it, and issue you with a Certificate of Compliance (see below) if it complies with safety requirements.

List of guidelines here (http://www.consumerbuild.org.nz/publish/diy/diylegal-electrical.php).

Billy T
24-10-2010, 08:46 PM
I'm pretty sure you are allowed to do your own wiring like this so legally he's all good and doesn't need it signed off. Insurance might be a different story though.

You definitely cannot do your own wiring unless it is supervised by, tested, and certified by a licenced electrician. Supervision may be 'general' but testing and certification is not optional.

Your insurance will be null and void if you do not comply with legislative requirements, and believe me, your insurers willl investigate very thoroughly if dollars are at stake.

From your comments and questions it is clear that you are not competent install this switch, and taking RB's advice would be further proof.

Cheers

Billy 8-{)

tut
25-10-2010, 12:40 PM
If it has a brown wire it is a flexible cable and doesnt meet the criteria.

(Moving switches, sockets and lighting outlets, but only if they are wired with tough plastic-sheathed cables).

BBCmicro
25-10-2010, 10:05 PM
In my previous house the homeowner had made some alterations and the metal conduit no longer touched the hot-point box. So there was no earth. (The conduit only had 2 conductors, the metal of the conduit being the earth).

When he came to wiring up the outlet the guy simply earthed the socket to the (floating) metal wall box!

That's why amateurs shouldn't work on wiring

Billy T
27-10-2010, 05:11 PM
In my previous house the homeowner had made some alterations and the metal conduit no longer touched the hot-point box. So there was no earth. (The conduit only had 2 conductors, the metal of the conduit being the earth).

You still had conduit wire??? :horrified :horrified :horrified

That is most definitely why amateurs shouldn't work on wiring; conduit wire only exists in houses that have never been touched since the day they were built. It is a shock and/or fire hazard in anybody's language.

The house probably had a wood-fired stove, asbestos insulation, a steam-driven electricity meter, long-drop dunny and a tin tub on the back lawn for baths.

Of course we should also allow that you may have a very long memory and that there were steam trams scaring the horses down main-street at the time you found this problem. :D

Cheers

Billy 8-{) :)