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Electrical

3 way switch - one switch overwrites the others

Anonymous user 09/03/2024 - 3.18 PM

I have a 3 switches that feed into a spotlight. Switch A is the first in the chain. B is the middle. C is the end. When I turn on switch A or C. It works great. They can interchange on and off no problem. But when I switch on B, this overwrite A and C and stops them being able to turn the lights off. For the life of me I can find the problem! B is the middle one in this diagram - http://www.lightwiring.co.uk/wp-content/uploads/2013/03/intermediate-switch-wiring-diagram-new-colours.jpg

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8 Answers

DEACON ELECTRICAL SERVICES

Rating: 5 out of 5
Grimsby
The feed ( common) is being switched. You need a tester or an electrician or both to diagnose.
Answered22 December 2020
2

Swalectrix Ltd

Rating: 5 out of 5
Truro
Double check the wiring on the intermediate switch, the L1 & L2 symbols don’t match the terminals on the other switch’s, I’ve always wondered why they are marked that way, can be confusing!
Answered22 December 2020
1

Anonymous user

You need to be able to identify the wires correctly. It will take an electrican ten minutes to sort. There is either an incorrect switch being used or a miswired switch. Switch B should be an intermediate, not a two-way.
Answered22 December 2020
1

Anonymous user

Is switch b an intermediate switch ? If you’ve recently changed them I would suspect you have used three 2 way switches. The middle one that has two three cores should be intermediate
Answered22 December 2020
1

Internal Repairs

Rating: 5 out of 5
Epsom
The middle switch is known as an 'intermediate' and is different to the 2 way lights switches at the beginning and end. Maybe it isn't an intermediate switch? One way to check is by loosening the switch and seeing if there are 4 wires terminated in the back. If there are just 3 then its wrong if 4 then correct. Check all the switches to see if any have 4 wires.
Answered22 December 2020
0

Springs electric interiors ltd

Rating: 5 out of 5
Bracknell
A and c should be wired up as a 2 way circuit and b in the middle should be wired up as a intermediate switch
Answered22 December 2020
0

Anonymous user

the middle switch must be an "intermediate" switch and have the common between A and B linked. If this is the case it could be that the "strappers" other cables are not wired as per the diagram you have added. Last straw is the switch is defective. not sure if you have opened the switches but check that terminals ( L1, L2) have the same colour cable, if everything is as per the drawing then i would change the switch.
Answered22 December 2020
0

Countryside Home Developments Ltd

Rating: 5 out of 5
King's Lynn
HI ALL THIS DEPENDS ON VARIOUS FACTORS. 1/ IS THIS EXISTING WIRING AND SWITCHES THAT WORKED PREVIOUSLY ? 2/ IF SO THEN MAYBE THE INTERMEDIATE SWITCH ( MIDDLE ONE) MAYBE FAULTY. 3/ IF NEW INSTALL THEN PROBABLY INCORRECT WIRING MORE LIKELY AT THE INTERMEDIATE SWITCH. THIS IS DIFFICULT TO DIAGNOSE WITHOUT BEING THERE WITH TESTER.
Answered22 December 2020
0