wiring help please

[craigersM]

hello all i am currently rewiring my house a need a bit of advice, hope this is clear

i have a light in the hall on the downstairs circuit that will be switched from 2 switches,
one as enter front door, which will also operate outside light (taking a live from switch and taking neutral an earth from celing rose-is this ok?)

and other at bottom of stairs, which will also operate landing light.

the landing light is on upstairs lighting circuit, and is connected to switch at bottom of stairs via 3 core and earth(from the switch to switch)

can i do the same and connect the hall switch to the switch at bottom of stairs with 3 core and earth?

my switches are to the best of my knowledge 2 gang 2 way switches.

does this all sound about right?

 

[ColJack]

yes it does..

2 way switching requires 3C+E cable..

run the switch wire from the light to the switch in 3C+E also, then you can take the switched live for the outside light back to the ceiling rose where you can then pick up the switched live, neutral and earth in one easy cable..

 

[ban-all-sheds]

(taking a live from switch and taking neutral an earth from celing rose-is this ok?)
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can i do the same and connect the hall switch to the switch at bottom of stairs with 3 core and earth?
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does this all sound about right?

Can you explain why you think you are competent to rewire a house?

 

[Taylortwocities]

I agree, BAS. scary t be asking such elementary questions when a rewire requires a much, much deeper knowledge.

anyways

to add a practical thing. Your downstairs switch will have power provided from two different fused circuits (upstairs and downstairs lighting).
This is a possible dangerous situation as some future owner of the house (or a visiting sparky) may turn off the downstairs lighting circuit and assume the switch is then isolated. It will still be energised from the upastairs circuit.

You must include a warning note inside the switch box, on the consumer unit and on the Installation Certificate that this situation exists.

You will be doing an Installation Certificate, won't you?

PS Edit: I don't think that Part P applies in NI and dont know the regulation there but don't you have to do something to legalise the work you are undertaking?

 

[holmslaw]

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[davelx]

It is not dangerous, it complies with the regs and does not need any warning notices.

this comes from 514.11-01 in 16th (don't have 17th here):

" A notice of durable material in accordance with Regulation 461-01-03 [16th], shall be fixed in each position where there are live parts which are not capable of being isolated by a single device. "

Unless that has been removed from 17th (which I doubt).

OK - you could correctly argue that the main switch on the CU provides isolation using a single device. However, rightly or wrongly, I bet the majority of people, including sparks, only turn off the specific circuit's MCB when working on an accessory, so it makes sense to include the warning notice in this situation to ensure that they turn of BOTH of them.

 

[ericmark]

It is not dangerous, it complies with the regs and does not need any warning notices.

this comes from 514.11-01 in 16th (don't have 17th here):

" A notice of durable material in accordance with Regulation 461-01-03 [16th], shall be fixed in each position where there are live parts which are not capable of being isolated by a single device. "

Unless that has been removed from 17th (which I doubt).

OK - you could correctly argue that the main switch on the CU provides isolation using a single device. However, rightly or wrongly, I bet the majority of people, including sparks, only turn off the specific circuit's MCB when working on an accessory, so it makes sense to include the warning notice in this situation to ensure that they turn of BOTH of them.

You must remember it says "isolated" this is done with an isolator not a MCB in most homes as the MCB is only single pole in most cases. So strictly to regs holmslaw is correct.

However I would not use the two wire method of wiring two way switches mainly because of EMC but also because borrowed lines can so easy become borrowed neutrals.

However the use of triple and earth removes this problem and so there is no reason why hall and stairs should not be two way or three way switched. Intermediate switches could be put at every door and if one wanted you could have a dozen switches all working same group of lights.

 

[davelx]

You must remember it says "isolated" this is done with an isolator not a MCB in most homes as the MCB is only single pole in most cases. So strictly to regs holmslaw is correct.

Yes - and I thought I made that point.

In any event, which is more important - complying with the regs, or stopping someone killing themselves? In this case, strictly complying with the regs only is less safe. My position remains that the vast majority of people will NOT turn off the main switch when working on an accessory, they will only turn off the MCB. It may be incorrect practice, but in the real world, you know it will happen and therefore IMO you are being negligent if you do not put the notice in place. If as a result someone is injured or killed you would thoroughly deserve to end up in court.

 

[Taylortwocities]

I agree, Davelx.

Someone will argue that you should use safe isolation procedures before working on any circuit. Using a warning notice complies with regs and (for me) is a belt & braces issue.

FYI in BS7671(2008) this is stated in 514.11.1 and 537.2.1.3

 

[chapeau]

2 way switching requires 3C+E cable..

Got a house where the landing light is done in twin and earth alone.

 

[sparkyspike]

Smells like a borrowed neutral.

 

[chapeau]

That's what I thought too. But not so. Very unconventional but all on same circuit and works. Previous owner was electrician who rewired the place, obviously didn't have any 3C + E lying around that day.

 

[ColJack]

why do you say that?
it was and still is quite common to use T+E as strappers and take the live to one switch and the switched live from the other using DI singles....

 

[ban-all-sheds]

Was very common for landing lights - take the hall switch drop, link the COMs, run T/E up to the landing switch, then a single to the landing light rose.

Only becomes a problem when up/down is split...

 

[holmslaw]

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