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Hi, I've just started an apprentice course so very green but I've been faced with this issue and can't work it out.

Two way light circuit in a garage each controlling 8 x 70w fluorescents. I've never seen a two way wired this way and need help understanding it. Each switch is identically wired and has a 3core + earth and a 2 core + earth inside the back box.

In each switch earth from 4 core and 3 core are connected together.

Re 4 Core, brown is connected to L2, black has brown sleeve and connected to L1, Grey has blue sleeve and connected to neutral from 3 core. Brown from 3 core is connected to common on switch.

I can't work out how this is functioning as a two way as there seems to be two 3 cores for load in? Also I need to remove one of the switches and put an occupancy sensor in which just has a live, neutral and switch live so unsure how to wire it.

Can anyone help me?

Thank you.
 
I assume Blue from the 3 core is connected to the grey (Blue sleeved) of the 4 core.

In which case, just considering the switching of the 'line (live).

On 1 switch:
Brown on 3 core is permanent live - which switches to the brown & black of the 4 core (called strappers)

On the other switch the brown and black (strappers) of the 4 core takes the switched live to the brown of the 3 core which feeds the first light!

If you draw it, it'll make more sense!
 
as he said ^^^^^ draw it out. makes it easier. also, you could apply to join the trainee section. questions asked in there by trainees are dealt with without any slagging off.
 
Problem with 2 way circuit. 2 wire 2 way switch wirin - EletriciansForums.net
Like this? 2 wire two way switch wiring
 
Thanks everyone. (Take onboard your comment telectrix). here is the diagram, although I'm not sure how the 4 and 3 cores are wired up. Richard, I think your diagram may explain it?
Problem with 2 way circuit. {filename} | ElectriciansForums.net
 
no pic.
 
still no. best not to copy/paste but insert image.
 
Telectrix, it seems to be asking for a url when uploading but this is just a jpeg loaded on my desktop. Do I have alter some settings somewhere?
 
Sorry your pictures are not coming up at one point it was limited before you had six posts but some recent security requirements have limited general posters from inserting images at all and I am not sure how this has gone on.
There should be a computer tab as well as the URL tab, but if not then a link to an image hosting site would work.

However my diagram shows exactly what you describe. same arrangement in all switches 1, 3 core; 1, 2 core in the same terminals.
Normally used when wiring with singles (using loop in) though my diagram shows 3+E and 2+E as this is what you have.
This is switch fed as this is easier with twin and earth.
 
select from computer, not url. then choose and opload.
 
Hi Richard again.

I've checked the wiring and it is what you've drawn so thank you for clarifying that. I now have a further issue. I need to replace the switch on the CU side with an occupancy sensor. The terminals required on the unit are live, switch live and neutral.

I'm thinking the live can be connected where the common was as this is the live from the CU ie the three core. The neutral again can be connected to the blue and grey blue. But that leaves me with just the switch live on the occupancy sensor but I have two wires left from the 4 core, ie brown and black/brown. Where do these go?

Thanks again.
 
There you have a problem, because the occupancy sensor is not a two way switch only a one way switch, however what you would have to do is have the occupancy sensor turning the light on when someone is present and the other switch manually turning the light on no matter what the occupancy sensor was doing.
Although if the light were switched off by the manual switch whilst someone was present then the light would stay on until the person left.

LNE to occupancy sensor
SL out of occupancy sensor to C on second switch
Live run to either L1 or L2 of second switch.
I.e. the switches are wired in parallel, either one turns on the light but both have to be off for the light to be off.

The other way is not useful in this case unless you wanted to control whether the sensor operated the light or not: switches in series both have to be on for the light to be on, any one goes off, the light goes off.
 
Last edited:
Thank you Richard. Yes the intention was for the manual switch remaining to just turn on the lights on manually as this switch is located near the door into the house. The occupancy sensor is near the garage door which I wanted to turn the lights on when the door was opened. Luckily the 3 core from the CU comes in at the garage door, switch to lights is at the house door end.

Could I ask you to draw what you're explaining? Just so I can be doubly sure?

Would really appreciate it. Thanks again.
 
if you're not bothered to 2 way switching, you could just wire the manual switch and the sensor output in parallel.
 
Thank you Richard. Yes the intention was for the manual switch remaining to just turn on the lights on manually as this switch is located near the door into the house. The occupancy sensor is near the garage door which I wanted to turn the lights on when the door was opened. Luckily the 3 core from the CU comes in at the garage door, switch to lights is at the house door end.

Could I ask you to draw what you're explaining? Just so I can be doubly sure?

Would really appreciate it. Thanks again.

Change from the top picture to the bottom picture
Problem with 2 way circuit. two way to manual and PIR - EletriciansForums.net
 
Thank you Richard. I really appreciate the time you've spent professionally drawing this up. I'll give it a go and let you know. Just one final bit of clarity. You've drawn the brown wire going to C on the front door switch. Is there an additional connection between L2 and C or is it just rerouted to C from L2?

Thanks again.
 

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