2 cables to each light switch

[alanabassett]

Can somebody let me know why there are 2 cables running to each light switch in my house?

 

[mrloy99]

I'd expect to see 4 lives, neutrals and earths in the ceiling rose - 2 for the the cables running to the switch, 1 from the previous light and 1 to next light - that's not the case there are only 3 of each. Confused.

maybe the one you are looking at is the last one in the circuit,ie no cable going out to next room?

 

[WarrenG]

Sorry, I still don't get it. Where does the additional cable run to? If there are 2 live, 2 neutral and 2 earth wires in each switch, why aren't there more wires in the ceiling rose

I think you confusion is the black neutral wire in the switch?

There are different methods to wire lighting circuits and therefore if it had been wired differently you may not of seen a black wire at the switch at all.

It is probably better if you try and get some info on different ways to wire lighting circuits.

Attached is a basic drawing for you of some ways:

http://www.tlc-direct.co.uk/Technical/DataSheets/MK/WiringDiagrams.pdf

Hope it helps!

Warren

 

[alanabassett]

Sorry guys - can I go right back to basics. Why are there 2 cables to the switches and why are the neutrals connector blocked? Why isn't there simply 1 cable to the switches?

 

[sivoodoo]

1. are you an electrician?
2. do the lights work?

If you are trying to modify the circuit in any way and you do not understand the concepts of what is involved then it is my moral obligation to avise you to seek profesional help. Get a spaky in, dont put yourself in danger!

 

[alanabassett]

I'm not attempting or intending to modify anything. I'm planning to change the switch and want to understand why it's wired differently to all the resources I can find on the internet. I am fully aware of my limits under building regs.

 

[mrloy99]

Sorry guys - can I go right back to basics. Why are there 2 cables to the switches and why are the neutrals connector blocked? Why isn't there simply 1 cable to the switches?

What are you doing farting around with the switches any way,I thought I'd never say this but GET AN ELECTRICIAN.

 

[pushrod]

I'd expect to see 4 lives, neutrals and earths in the ceiling rose - 2 for the the cables running to the switch, 1 from the previous light and 1 to next light - that's not the case there are only 3 of each. Confused.

you commonly get three cables to a ceiling rose power in, power out and switch cable.

 

[alanabassett]

Thank you so much for your advice. I'm more than capable of changing a switch. I was kust interested in why the switches were wired in such a way. Clearly you can't tell me.

 

[Guest123]

They are wired that way because...... they just are.

Every spark has different ways of doing most things, not right or wrong just different.

The only guy that could tell you why he wired it like that is the guy that wired it.

 

[marshr02]

Alanabasset.

The two standard methods of wiring lights have the 'busy' end either in the ceiling rose or in the light switch. Often an electrician will decide which methods based on the toplogy of the building - his aim to reduce cable runs and avoid junction boxes. These two methods of wiring lights are being superseded, mainly due to the changing use of lights, such as previous posts for downlighters, or the increasing provision of a neutral in the switch for future PIR switching or the like.

For ages now the light switch had no neutral as it's not needed for simple switching of tungsten lights. More techy methods such as replacing the light switch with a PIR or some form of electronic device work better with a neutral, rather than drawing their own supply via the 'load'. If the 'load' ie the light is now low energy then the current drawn is often too low to power an electronic switch device - hence the neutral.

In your example I agree with all the posts to date. Sounds like the wiring methods doesn't conform to 'ceiling rose' or 'switch loop in loop out'. One cable into the switch comes from the consumer unit, the neutral in is carried out on the 'exit' cable along with the switched live - this cable now going direct to a ceiling rose(s) (with likely no other cables in the ceiling rose)