Anyone work this one out.

[Dunc]

Went to a quick job the other day where the customer had tried to replace the hallway and landing light switches with chrome accessories and failed dismally. I was called in expecting a nice simple job but i was thoroughly confused by what i was met with.

The hallway and landing lights were both two way from upstairs and downstairs (2G switches at both points). The upstairs and downstairs lights were both on separate circuits with the feed at the respective roses and a twin dropped to the closest switches (1 twin from landing light to landing switch and 1 twin from hallway light to hallway switch). The strappers were 2 x twins between switches. The customer was insistant that both switches used to operate both lights. I can see how it could have been done but only with a potentially lethal method (and that didn't involve using the CPC as an extra strapper!). Any idea how it could be done other then dangerously. I left them with a the landing light 2 way switched and the hallway switched from the downstairs only.

Let the head scratching begin! :smug2:

 

[Des 56]

Same conclusion as yourself
hall light feeding common of landing switch in the hall then strappers up to landing and switch wire to landing light
Then landing light feeding hallway switch on the landing, strappers down to hall switch and switch wire back to hall light

This would have been ok if they were fed from the same circuit
It may be hard work trying to convince them it was wrong originally

 

[GLENNSPARK]

couldn`t you pick up the extra strapper at the rose? Take for example a 2 way switching on a single pendant for instance: just 3 core from switch to switch and break into the switched live (black) from both at the rose then the grey goes straight through switch to switch....

 

[Marvo]

Not sure if I understand you correctly but I've seen 2-way systems wired like this.

 

[Blowcat]

I hate these kind of jobs, sound easy on the phone but a different picture when your there.

Whats the loading like, could you put the 2 circuits into the one mcb so to avoid a borrowed neutral.
Not perfect but at least your leaving it safe.

(Nice pic Marvo)

 

[Dunc]

Not sure if I understand you correctly but I've seen 2-way systems wired like this.View attachment 7131

That's exactly how I think it was connected, it works but with it being fed by two circuits it will be fused at roughly 12A and have two points of isolation which is potentially very dangerous. Council job apparently! The load would have been okay to put on one circuit however that would leave the customer with no lights if the circuit tripped which is dangerous IMO.

 

[mickys86]

I don't think there's a way round that except a partial re wire of the circuit. Good luck

 

[Marvo]

That's exactly how I think it was connected, it works but with it being fed by two circuits it will be fused at roughly 12A and have two points of isolation which is potentially very dangerous.

The circuit will work but I agree it could be dangerous if both supplies from the CU aren't from the same MCB. It could also be dangerous if the CU is 3-phase, if someone tries to balance the load and spreads the lighting across different phases there could obviously be a problem. I'm not sure if it's compliant with the UK regs or not, it was just a suggestion how it might be wired if there's only two wires running between the 2-way switches.

Good luck finding the problem and be careful if there's 2 points of isolation on the one circuit.

 

[BlueToBits]

Are you sure the hall switch strappers do not pass through the hall rose or a JB under the floor? That could free up one strpper core and one core of each switch wire for a neutral between the hall and landing light.