Wiring For An Outside Switch

[ives31]

Hi,

Forgive my total ignorance about electrical matters but I'm trying to replace an external switch outside my garage.

The new switch I bought from B&Q is totally different to the old one hence my confusion.

Basically, the new switch has three terminals marked COM, 2 WAY and 1 WAY.

The old wiring from the old switch has 2 red wires, 2 black wires and one earth.

I can see where the earth goes into the new switch but I'm stumped where the 2 black and 2 red wires go.

Can anyone give me any pointers?

Thanks.

 

[Andy™]

what cables were where in the old switch?

and if its wired the way i think it is, you should have 2 earths

 

[ProDave]

Almost certainly the two blacks just join together in a terminal block.

One red to COM, the other red to 1 WAY

But please please please, anyone reading this thread, BEFORE you disconnect the old switch make a note of how it is wired or take a picture.

The earth will probably be two wires twisted together with one bit of sleeving over them.

 

[ives31]

Thanks for the reply guys.

Sorry to be such an idiot.

A bit more clarification:

In the old switch body (rather than in the switch itself) there were two screws/ terminals on diagonally opposite corners. One was an earth (2 wires twinned together, as you said). The other terminal had the two black wires together. Out of this terminal with the 2 black wires came a yellow wire with an LED on and that went to a terminal on the switch which had one of the red wires going into it ( I guess this would be COM 1 on the new switch)

 

[ProDave]

That NEON was to show when the switch was turned on.

If the new switch has the same neon connect it the same. But since you have lost track of which red wire is the feed in and which goes out to the light, you will have to try one of them, and if you find the neon stays on all the time then move it to the other one.

 

[Sidewinder]

OK, it "appears" from your posts that the earths are earths.

The two blacks are two Neutrals, as there is a neon across the blacks and one of the reds.

So, join the blacks in a separate strip connector.

Join the earths in a separate strip connector.

Connect one of the reds to the com and one to the L1 terminal.

If, you have explained things correctly, and I have understood your posts without seeing the job, you should be good to go!

 

[Evans Electric]

Ives's description ( As a non-electrical person) was better than some from so-called tradesmen TBH  .   

 

[ives31]

Many thanks guys. Got it working fine.

Thanks for all your help!

 

[poni]

hi all would the light being on not tell him that the light was on? and the neon so he could find the switch in the dark ,as its out side? 

so the neon should be across the feed (red in) and natural (black)  

 

[ProDave]

hi all would the light being on not tell him that the light was on? and the neon so he could find the switch in the dark ,as its out side? 

so the neon should be across the feed (red in) and natural (black)  

That's also a perfectly valid way of wiring it. It depends what you want the neon to actually indicate.

 

[Evans Electric]

You're probably right there Poni , and some are across L & Sw also .  The MK Sentry ones do that .