View Full Version : Off Topic - Light Switch Wiring, need explaining

Noel Nosivad
03-01-2004, 12:38 PM

I've tried searching for explanations on this but it's either some foreign or old way of wiring.

What I'm am trying to accomplish is have two switches control one light fixture.

I need someone to help explain the light switch, what "1", "C", "2", and "Loop" are and how would I wire it up if I wanted to have to switches control one light fixture?

I've looked at the switch, and I wasn't able to find my voltmeter to find out which was the power and which was the bulb but in the layout of the switch I had both black wires connected to the Loop, and then one red wire on "1" and the second wire connected to "C" and nothing connected on "2".

Could you determine the power source by linking which red wire is to what by the way it's been setup?


Noel Nosivad

P.S. Sorry for the off topic, I didn't know where else to try.

03-01-2004, 01:00 PM
Should you be playing with such dangerous voltages without full knowledge. Death IS permanent, and takes all the fun out of life. :D

Phase (red or brown) should go to Switch 1 (SW1) C , Light (red or brown) should go to Switch 2(SW2) C , Neutrals (black or blue) should common together (loop). and SW1/1 should connect to SW2/2 and SW1/2 should connect to SW2/1.

Just incase it is not too clear, SW2/1=Switch2 terminal marked 1.

03-01-2004, 02:42 PM
Nice picture hre (http://danswiringpage.com/3way_ani.htm)

03-01-2004, 04:23 PM
The loop terminals have no involvement in the switching process, just a connection for the Neutrals.

There is no guarantee that the switch would have been wired originally with the live feed phase to the C (common) terminal.
Thats what's intended but in practice, but where no loop-on of the live feed phase (to another switch) is used it could be either in the Common or 1-way switch terminal.

The 2-way terminal is only used in 2-way switching.

The light circuit phase should be in the 1-way terminal, but as above it could easily have been transposed with the Common (Live feed).

As above, death is very permanent.
Testing on completion by a qualified person to AS/NZS 3000 is also law, to assure safety.

03-01-2004, 04:29 PM
Re-reading your post, you need "strap wires" 1 - 1 and 2 - 2 between each switch.

Live feed phase to C on one switch.
Light circuit phase to the C terminal on the other switch.

Also while some switches have terminal 2, its sometimes a dummy that doesnt make a connection unless the switch was purchased as a 2-way.

Recommend employing an electrician, for your safety and and continued insurance on the property.

Noel Nosivad
03-01-2004, 05:47 PM
I'm trying to understand this. The diagram doesn't provide wiring and I already knew how to draw a schematic diagram of the circuit, just understanding the switch is the problem as I'm not sure whether 1 wire or 2 wires are selected when in the on position or whether one or no wires were selected in the off position.

So if the switches aren't two-way because "2" is possibly a dummy, I could not make a connection with 2 switches where either one can switch on or off the connection?

It would just be one of the switches wouldl be able to turn it on/off as well as the other, which is basically the same as having just one switch?

Thanks for the information so far. It's been great.

Noel Nosivad

03-01-2004, 06:05 PM
The mechanics of the switch work as fillows:

C connects only to 1 in switch position "on"
C connects only to 2 in switch position "off"

Nothing connects to the loop terminal in the switch.

The problem with some 1 way switches is that the tip of the connection on 2 is missing, so there can never be a connection C to 2 in the "off" position. You need to verify this with an ohm-meter when the switch is totally disconnected from the mains.

You sound as though you are unfamiliar with the system, and again I urge you to use qualified persons to do this work. Its a legal requirement in NZ.
Somewhere in the future, someone will perform maintenance after you have done the wiring, and any non standard work then puts others lives at risk.

Graham L
04-01-2004, 02:20 PM
Replace the switch with a cord switch. Use long strings to each place where you need to operate the switch.

String is wonderful.:D

04-01-2004, 04:29 PM
Definitely agree on that point. Electrician's charges may cost you a bit of money in the first place (unsure, but guessing about $100 plus materials), but in the long run will gurantee legal compliance, and ensure there is no risk to you, or anyone who uses the light(s).

Especially as you do not seem to be too familiar with electrical wiring, what you are doing is likely to put your life at risk. Please, please take care if you do decide to do it yourself. Your friends and family will certainly want you to be around in the future.

04-01-2004, 04:30 PM
And if you do do the wiring yourself, do what Godfather said and get it checked out by a qualified electrician. Nobody likes to hear about friends/family being killed or seriously injured while doing electrical work.

05-01-2004, 12:24 AM
How are you meant to learn if you always get someone else to do it. I know OSH and ACC don't want anyone to take a risk but that could also create a useless society.
They are just having trouble understanding the correct terminals to use.
The easiest way to put your life at risk is to leave it hot while you attempt it.

05-01-2004, 01:13 AM
> How are you meant to learn if you always get someone
> else to do it. I know OSH and ACC don't want anyone
> to take a risk but that could also create a useless
> society.
> They are just having trouble understanding the
> correct terminals to use.
> The easiest way to put your life at risk is to leave
> it hot while you attempt it.

OSH and ACC can hope for it, but the law (Electricity Regulations 1997)demands compliance. Its not optional.
I don't think that mikebartz has the authority to sanction a dispensation from the Regs?

Replacing a switch is one thing, but they are wanting to run new fixed wiring to a multiplex switching arrangement.

Some other issues.

The cabling required (2 x phase TPS) for the strap wires is not usually readily available, except for trade purchases.

Using readily available TPS (red, green, black) will cause someone else to have a nasty accident at some time later.
Thats just one reason why its not a good idea.

Look past the obvious risk to the novice installer, to the risk posed when they are no longer there and someone has to work on or test the house wiring, not knowing of the polarity reversal. Ouch.

As above, if you are going to DIY you must get it pressure tested and signed off (with a CoC if needed) by a registered sparky.
Its even possible that your house insurance could be invalidated without having it done properly.

05-01-2004, 01:43 AM
>OSH and ACC can hope for it, but the law (Electricity Regulations
>1997)demands compliance. Its not optional.

Actually the law has changed somewhat if you are doing some work on your own house. As I understand it he may have to run new wiring from the switchboard which is not allowed but general changinging of switches etc is.
The crazy thing is that you are now more restricted in what plumbing you do than in what electrical work you do. Which is more dangerous?

>I don't think that mikebartz has the authority to sanction a dispensation
>from the Regs?
I think we both need to get some facts right.

Neil McC
05-01-2004, 07:54 AM
The way I understand the law at the moment is that a homeowner can do work on his own home,no one elses.And may not go into the switch board/meterboard.And any work done needs checking by a registered inspector.I, as a licensed/registered electrician ,am not allowed to issue a compliance certificate for that sort of work.Also if you are working for an employer who wants you to do electrical work,that is not allowed,as it's against the law to get paid for electrical work on someone elses property,unless you're licensed of course!I have this problem with a firm I do work for,as one of the employees
did the odd bit of "fixing up",until I pointed out the risk he was taking with other peoples lives.For which I certainly wasn't going to cover him. And of course I get the odd new homeowner who wants to run all the cables,which can lead to me spending time sorting it all out again!

05-01-2004, 08:09 AM
The point is when someone doesn't know the basic theory needed to wire dual-switches, then it can be easily assumed that they have little or no experience in electrical wiring at all. It is not the immediate risk to this homeowner of concern, as they are willing to take it, but to future users and owners of the property who are at risk when modifying and using the home.

I have seem quite a bit of dodgy and illegal wiring in many places before, and would strongly urge the person concerned to enlist the skills of a registered electrician, for the safety of both himself, and future users and owners of the home/building.

Billy T
05-01-2004, 09:42 AM
> OSH and ACC can hope for it, but the law
> (Electricity Regulations 1997) demands compliance.
> It's not optional.

As usual, Godfather is 100% correct, though there have been further amendments to the Regulations since 1997

> Actually the law has changed somewhat if you are
> doing some work on your own house.

No, the law has not changed in that respect.

> As I understand it he may have to run new wiring from the
> switchboard which is not allowed.

Your understanding is incorrect. Homeowners may run any type of wiring they wish but they may NOT connect it to the mains. Connection must be done by a licenced electrician who must test the wiring first and issue a Certificate of Compliance afterwards

> but general changinging of switches etc is.

As above. Homeowners may not work on live wiring or connect wiring or appliances to the electricity supply other than by plug and socket connections. Livening must always be carried out by a licenced electrician.

The need for twin red for the strap-wires can be ovecome by running parallel two or three core, using the red conductors only and cutting off the black and green at the termination points. Cost is slightly greater but you cannot put a price on safety. Alternatively, three core can be used and the electrician will sleeve the second active conductor Red at both ends which eliminates any potential danger.

Finally, if damge or loss is incurred due to faulty home-owner wiring (which pre-supposes that a Certificate of Compliance was not obtained) your Insurance Company will almost certainly reject your claim.


Billy 8-{)

17-02-2005, 03:33 PM
Thank you to contributors with knowledge in this field.

What about a single light with a simple switch.

Seems that the two wires connecting to the switch should be of the same colour. (either red/brown/phase or blue/black/neutral).

However, one imagines that most would use standard 3-colour cable to wire the switch. If so how would one resolve the colour issues.

Billy T
17-02-2005, 04:32 PM
There is no colour problem for a single switch. A two or three core cable: red & black + green, or brown & blue + green-yellow cable feeds the switch. The third conductor (green or green yellow) is only needed if the lamp requires a safety earth.

The black (blue) wire goes to the loop terminal, a red (brown) wire goes to one switch terminal and another from the other side of the switch to the lamp. A further black (blue) comes back from the lamp to join the other black (blue) wire in the loop terminal.

If the light fitting has exposed metal that could become live, the green/yellow wire runs up to the lamp and is connected to the earth terminal. Because the cable is usually cut at the light switch, the green/yellow wires are connected together using a blind-end screw connector.

Remember that unless you are licensed to carry out electrical work, you may install the wiring but you are not permitted to connect it to the live supply.

If you reread the previous posts in this thread you will see that there can be insurance complications if a fire is caused, or funeral complications if you get it all horribly wrong. Put politely, if you have to ask how, you probably shouldn't do it.


Billy 8-{)

17-02-2005, 11:35 PM
My old thread, ahh the memories KK = Noel Nosivad.

Thanks to all the suggestions, no-one was injured during this.

I have experience in wiring 3 pin plugs, fixing extension cords, etc, but when it came to working on the light switch, I could draw the schematics, but I couldn't implement it, as I had no idea of how a 2-way switch (is that what it is?) worked, I know how a simple switch worked, where 1 is on and 0 is off/no wire, found on your power supply on computers.

I wired it all up, got it working. I then got it inspected. The electrician told me that you can work on anything less than 240V, most appliances require a Certification for Appliances and I think there's 3 different classes, there's one there for you computer technicians if you want to do it, it just guarantees that you can work on the electrical side of things for it.

Although, I sadly admit, I've forgotten how to do it, and the switch has now been fixed into the wall for some time now, just when doing this, we never considered where the best place for this additional switch should go, but it's good enough.

Answers do lie within this board, so thanks for everyones help. I do have an interest in Electrical, but mainly Automotive.


18-02-2005, 11:35 AM

28-03-2005, 04:41 AM
Hi all,

I live in the U.K and the law says that I need a qualification to mess with the wiring in my or your home BUT I play around with a shop or factory's electrics as much as I like without any experiance.

The law is an ass.


30-08-2005, 09:53 AM
Hi from Canada. I found this message board looking for information on NZ wiring. I bought two light switches at Mitre 10 when I was last in Auckland, as I like their look and feel and want to install them in my home in Toronto. I am looking for some schematics for the light switch itself. I read the above posts and understand there are 4 contacts in the switch: 1, 2, C, and Loop.


Graham L
30-08-2005, 02:31 PM
Welcome to PressF1, Sunboy.

The "loop" terminal is just that. It isn't connected to anything inside the switch. It's intended for joining two or more wires which need to be joined.

The "C" terminal is the "Common" of the single pole double throw switch. and "1" and "2" are the two sides. Switch operation gives C-->1 one way, and C-->2 the other way.