Two Way Light Switch Issue

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Goosey

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#111856 16-Nov-2012 21:07

Hi,

We have a light at the top of some stairs.
There is a single switch at the bottom of the stairs and at the top of the stairs there are a set of 4 switches. One of these for two way operation of the light switch.

Issue:
When the switch at the bottom of the stairs is off, we cannot use the switch at the top of the stairs to turn on the light.

When the switch at the bottom of the stairs is ON, we can use the the switch at the top of the stairs to turn on the light.

Is this caused by the 'loop' terminial? Is it susposed to be used at both ends or just one?
I havent actually looked yet however Im positive (no pun) that the loop is being used at the bottom of the stairs on the single switch. Im yet to take a look at the switch at the top of the stairs.

Thoughts?

RunningMan

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#718507 16-Nov-2012 21:30

If you don't know the answer to this, please call a sparky to sort it out - worst case scenario, you could kill yourself if you get it wrong.

Goosey

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#718511 16-Nov-2012 21:43

RunningMan: If you don't know the answer to this, please call a sparky to sort it out - worst case scenario, you could kill yourself if you get it wrong.

I understand... Im already dark....dont need to be more dark.
Just asking so I an gauge what the problem is.

richms

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#718516 16-Nov-2012 21:47

Add to that, older 2 way switches were installed in a particularly retarded way that would switch each end of the light between live and neutral which could leave the lamp holder live on both sides when the light appears to be off.

What you have described is either one of the 2 travelers has become disconnected, or one of the switches has failed on one terminal. Nothing to do with the loop terminal. As old installs were permitted to use the green wire (in theory with a sleeve but seldom done) as a traveler, it can make if very very confusing if you arent used to it and can even confuse many "competent" electricians, so even if you find for example a green wire loose you dont really know where it should go and can make a real mess if you get it wrong. So just call a decent sparky to have a look, and dont be surprised if it was never installed properly and needs the traveler cable replaces with some 3 core to make it legit to be fixed up.

Richard rich.ms

mattwnz

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#718522 16-Nov-2012 22:13

The contacts in the switch possibly need cleaning. Had this happen myself. If you have a good quality switch it may be able to be opened, but if you get an electrician in they would probably switch the switch for a new one.

Niel

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#718526 16-Nov-2012 22:30

If you just want the information for reference to check if the electrician will spin you a story, read on, otherwise, stop reading.

"Loop" is for connecting together extra wires. It is not connected to anything else. The correct way of installing a 2 way switch is power comes in the common terminal of one switch and the "on" and "off" terminals each have a wire going to the "on" and "off" terminals of the other switch. So there are 3 wires connected each end, plus the "loop" is used to join say the neutral wire, and a terminal block (because there is only 1 "loop") joining the earth wires.

There is a chance someone installed the switches not knowing how it is done, and simply wired the 2 switches in series. Or else one of the two wires linking the switches broke off or the switch contact is warn/dirty. For the cost of a switch, I'd replace the switch rather than clean a heavy duty contact that somehow became intermittent and cannot switch a low power circuit. Electrical Direct is a good source. Some brands make more money by selling a special 2-way switch rather than witting the second contact to all switches, so just check before you buy.

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richms

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#718529 16-Nov-2012 22:36

Hmm, thats a different way to how I was told to do mine here,

Juice goes into 1, 2 goes to the lamp, and 1,2 and C are connected to the corresponding terminal at the other end thru a piece of 3 core r/w/b cable, with any intermeidate switches having the wires from 1 and 2 going thru the intermediate mech and the one that goes between the C's going straight thru.

It does get messy in the lounge where there is multiple circuits with multiple intermediate mechs and the lamps connecting at the inbetween switches as well, but it seems that so long as the juice is put into 1 and out of 2 at any point along the traveller it works out ok. Someof the flushboxes here are way too full so I will be glad to see the back of all that crap and the lack of scenes etc when I redo the lounge and go cbus or something ;)

Richard rich.ms

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Niel

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#718530 16-Nov-2012 22:50

That will also work, but I know which one is much more logical:
http://www.electronics-project-design.com/LightSwitchWiring.html
And you either have to use the different coloured wires (our house has it in a yellow jacket) or you must put a colour sleeve on the wire ends as per the electrical rules.

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gzt

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#718533 16-Nov-2012 22:56

richms: Add to that, older 2 way switches were installed in a particularly retarded way that would switch each end of the light between live and neutral which could leave the lamp holder live on both sides when the light appears to be off.

!!!! 0_0 !!!!! surely that was illegal even at the time?

richms

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#718546 16-Nov-2012 23:14

Yeah, except normally the power to the lamp is coming out of the same swichplate that you put the mains into, so taking it back thru the traveller results in needing another blind joiner to connect the wire out to the far switches C terminal back to the incoming or outgoing phase, whereas using 1 as in and 2 as out means you are joining in the terminal.

Sleeving greens to make it live isnt allowable now thankfully, friend got caught out on a house he was doing up to sell when the sparky said no to working on the 3 way switched lounge lights with green sleeves in it (thats the mr whippy song isnt it?) and in the end just disconnected the switches since noone checks the lights work as you expect at an open home. Perhaps the OP has bought that house? Not in mt wellington are you?

Richard rich.ms

richms

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#718548 16-Nov-2012 23:18

gzt:

!!!! 0_0 !!!!! surely that was illegal even at the time?

Friend found it in his ex state house, and it was even run with single core red cable in the nasty old rubber jackets, nicely cable clipped along the way, so was either done by a pro at the time or someone intent in pretending it was done by a pro.

Richard rich.ms

gregmcc

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#718580 17-Nov-2012 05:43

As an electrician, it does seem that the switch is faulty, don't even bother trying to go down the path of cleaning the contacts yourself, not worth the hassle, just get a sparky in, any sparky should do as domestic wiring is the easiest to do.

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DarthKermit

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#718601 17-Nov-2012 08:12

Can you upload a pic of the light switches? That way people could tell probably how old your installation is.

Whatifthespacekeyhadneverbeeninvented?

Goosey

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#718613 17-Nov-2012 08:44

Hi all,

Will try to get some pics. I believe my best bet is to 'view' only the wiring into these switches. If that doesnt match then we know Ive got a nice little problem.

The switch at the bottom of the stairs was replaced by me about 10 years ago, the switch at the top of the stairs has been there since the house was built in 1989/1990. The house was built by a sparkey....so weve enjoyed all sorts of little odd issues from time to time with regards to the wiring.

From memory, I think that the potential for the contacts to be blown on the upstairs switch could be correct as the lights used to have full metal holders and twice they arced out abd blew the switch at the bottom of the stairs and fuses before these lights being replaced by a sparkey. Perhaps when the sparkey replaced the lights he didnt notice the two way switch wasnt working properly because the switch at the bottom of the stairs was already on (or just didnt know there was a second switch as that switch is through a doorway at the top of the stairs).

Thanks for the conversation.

Will post an end result at some stage.

Niel

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#718649 17-Nov-2012 10:12

Pull the fuse before you look at the switch wiring, especially if you know there is "interesting" wiring in the house.

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