Architrave Light Switch

[Hootsmon]

Hi,

I've got a replacement new HPM switch for the main room lights to replace the old one. There appears to be 3 holes in the back labled "loop, 1, C and 2 which is blanked off. When the electrician comes to wire it up which ones will he use?

Regards,
Gordon

[johnc]

Does it matter, when he arrives he is bound to know which one, but why wouldn't you let him get the switch?

[Ashore]

Proberly the same ones in use on the existing switch :2tsup:

[DJ’s Timber]

I could tell you, but I am not qualified so will leave it to the sparky you have got coming :2tsup:

[MrFixIt]

Hi

Hi,
I've got a replacement new HPM switch for the main room lights to replace the old one. There appears to be 3 holes in the back labled "loop, 1, C and 2 which is blanked off. When the electrician comes to wire it up which ones will he use?

Seeing no one else has really helped answer your question, here is a little bit of info for you :)

First, light switches (at least ALL the ones I've used) have 4 holes. Which is like you describe.

The connections are used for the live wire, the return to the light itself, the one that is blanked off is used when you have a two-way switch setup (two separate switches controlling the same light fitting), and the last connection does NOTHING :D

Well it does do something - sometimes :) It is/can be used as connection point to allow connections to other wires. It used like a terminal block to connect multiple wires.

DON'T FIDDLE :no: with the switch though UNLESS you know what you are doing. Electricty kills and electric shocks :oo: are not much fun, I've had a few over the years.

[MrFixIt]

Hi Grodon

Help ma boab, the bairns goat it awe wrang!

Help my BOAB??, the kid's got it all wrong.

What is boab? Is it Baby?

[Hootsmon]

Hi Grodon


Help my BOAB??, the kid's got it all wrong.

What is boab? Is it Baby?


Google "the broons" or goto http://www.thatsbraw.co.uk/The%20Broons/Broons-Page.htm

[Pulse]

Normally,

Terminal 1 would be the active to the luminaire.

Terminal 2 is only used for 2 way switching eg stairs, hallways, rooms with two doors.

The common terminal is where the active from the switchboard is connected. Normally two would be connected there, the active supply coming from the last switch and the active supply going to the next switch.

The loop is not always used, it is not actually involved in any switching at the switch and the black neutral wires are often simply joined here (ie neutral from luminaire and neutrals of the main circuit)

Of course you probably don't nee dto tell the sparky this, they would know already :)

Cheers
Pulse

[Barry_White]

Phew

Glad someone else answered that. Saved me from getting jumped on from great heights because I usually can't help myself answering such highly technical questions.

[Metal Head]

I could tell you, but I am not qualified so will leave to the sparky you have got coming :2tsup:


You could always PM him instead. Then we couldn't sue you if you were wrong:wink: :).

[Hootsmon]

Normally,

Terminal 1 would be the active to the luminaire.

Terminal 2 is only used for 2 way switching eg stairs, hallways, rooms with two doors.

The common terminal is where the active from the switchboard is connected. Normally two would be connected there, the active supply coming from the last switch and the active supply going to the next switch.

The loop is not always used, it is not actually involved in any switching at the switch and the black neutral wires are often simply joined here (ie neutral from luminaire and neutrals of the main circuit)

Of course you probably don't nee dto tell the sparky this, they would know already :)

Cheers
Pulse

OK so if the sparky isolated the circuit, took off the old switch in a circa 1950's house he would see an old switch with 2 black and 2 red wires. Would he then combine the two red into C and the two black into Loop? He never turned up today so I didn't get a chance to ask him.

[null & void]

OK so if the sparky isolated the circuit, took off the old switch in a circa 1950's house he would see an old switch with 2 black and 2 red wires.

I don't spose the cable was enclosed in black outer insulation by any chance ?

[Hootsmon]

Black outer insualtion Yup

[Ausyuppy]

OK so if the sparky isolated the circuit, took off the old switch in a circa 1950's house he would see an old switch with 2 black and 2 red wires. Would he then combine the two red into C and the two black into Loop?

Hootsmon,
Sorry if this comes across wrong, however if you need to ask these questions I dont think you should be touching this switch. Get the sparky to do it.

If you were to join the two red wires together and the two black wires together (depending on how its wired) you would be bypassing the switch and all it really would be is a connection block. However depending on which position the switch was in, you could potentially be creating a short circuit.

I have had to fix a fault when my Uncle tried to change a switch. He was confused as no matter what way he wired it, it wouldnt work. One way he was switching lights off over half the house, another way the light in the room just didnt work, and another way he was blowing fuses.

I dont blame you for wanting to do it yourself as sparkies cost a fortune, but a burnt down house or death is definately worse.

Good luck
Steve

[null & void]

Black outer insualtion Yup

Then you're most likely up for a whole rewire not just a switch replacement.

The black stuff is plastic insulation which falls apart after a number of years leaving bare uninsulated copper and apart from being dangerous is also a fire hazard. Any decent sparky probably won't touch it until the cabling has been replaced. I'd be getting someone out to give you a quote to replace it all and do an inspection to see much of that cable there is.

[Pricey]

You need to understand that in older installations the neutral was looped at the switch in order to reduce the amount of cable used. These days the active supply is run around the ceiling, with a switch wire run down to the switch (most of the time). This way the loop is made at the light fitting.
Were the 2 black wires joined together? Were the 2 reds joined? These 2 questions need to answered before any qualified electrician can decide on the necessary action.
If the 2 blacks were joined and the 2 reds not, then the 2 blacks would go in the loop and the 2 reds would be 1 each in common and 1.

REMEMBER......All connections should be made with the MAIN switch turned OFF. If the switch will not work then someone suitably qualified will need to test the circuit out for proper connection.

[Hootsmon]

Thanks for clearing that up. I appreciate the reluctance to part with this info. I'm from the UK and grew up watching my dad do all of this sort of stuff. However if you guys want a real scare then look up some of the UK DIY websites :) Thanks again

[thatirwinfella]

Thanks for clearing that up. I appreciate the reluctance to part with this info. I'm from the UK and grew up watching my dad do all of this sort of stuff. However if you guys want a real scare then look up some of the UK DIY websites :) Thanks again

you think the DIY might be bad, i've seen the "professional" stuff. At work we had test equipment sent over from the UK, with plug tops that needed to be changed to the OZ standard. It was shocking, strands were missing from the flex, the terminals were screwed down direct onto the insulation, and the ends of the cable weren't crimped.

dodgy, dodgy dodgy.

And some of the engineers on here wonder why they can't do work themselves.