Help/suggestions with External Light or Junction box...

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Hopefully somebody might be able to make sense of my waffle.....

New house (to us)...we have an external wall light outside the kitchen door – it is on the downstairs lighting circuit and the first point of call from the consumer unit for the Live feed.

Originally this must have had a switched live from one of the switches on a two gang switch just inside the kitchen door – the switched live currently ends in a terminal block in the light housing as whoever fitted the current Dawn-Dusk light connected it, understandably I guess to the permanent live.

The live to the two gang switch also provides a live for the two way circuit for the kitchen light.

Something along the lines of Fig.1 attached (albeit wiring is actually red/black).

We don't really need/want the outside light as I have some new lighting going up so ideally I would like to pull these cables back, make a new connection for the circuit in a junction box above the ceiling and just take take a new live down to the switch for the kitchen light – only issue is access as the bathroom is above and that isn't currently on our “to do list”...so until it is when such a job would be much easier my best options appear to be fit a new light that's acceptable in appearance or perhaps just a suitably rated external junction box.

The cable tails out of the wall are pretty short though, could do with a clean and appear a little brittle – when I tried to clean one up and straighten it a little it just broke away making it even shorter !

As yet I haven't found a wall light with a housing with enough space so wonder if anybody might have any suggestions for an external light with a reasonable “back box” on it or a external junction box with just a back cable entry ?

As ever, thanks for any suggestions and input.

Rgds
Freddy
 

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Are you sure about connections? The circuit you have shown is what is taught in schools, but in the real world we don't go around in a circle, but wire as I have shown. We should use triple and earth cable to ensure we are not transmitting 50 Hz hum to radios and like, but where I have put the circle it was common to borrow a line connection from another lamp so that twin and earth could be used. As to junction box it should need a tool to gain entry, but it is hard to make any box fully water proof, so just fill with petroleum jelly so there is simply no room for water to get in. The problem is air expends and contracts a lot so when contracting it can suck in water, petroleum jelly does not expand and contract to same extent so it does not suck in water.
 
Thanks for the reply ericmark...

Not there at the moment but yep, pretty certain its just two core and earth running from one gang to another....switched live for the kitchen light just single core and earth.

Need to check but likewise I suspect on the upstairs landing light which appears to take its switched live from the switch at the top of the steps but that's fed from the switch at the bottom of the steps – neutral picked up from upstairs circuit :(

Wish I'd realised earlier and I could have perhaps run new cables for the lights and had it checked/signed off when we had a new Ring upstairs !

As for the external light if we put a new one that acts as a “Junction Box” until such time as I can pull them back to a internal junction box covering the connections/terminal blocks Petroleum Jelly would perhaps be suggested then to act as some protection from moisture – or would you still suggest filling any recess completely – is Jelly completely non conductive ? I have some Wago connectors (Push fit or lever) I was going to use as they are little more compact than terminal blocks.

MTIA,

FF

Edit: Not sure what Petrological Jelly is - corrected !
 
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You can get specific Magic Gel that is non-conductive, but it is hardly ever necessary for a surface-mounted box that is at least IPx5 rated.
Assuming that you do the cable entry bits correctly!
 
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Need to check but likewise I suspect on the upstairs landing light which appears to take its switched live from the switch at the top of the steps but that's fed from the switch at the bottom of the steps – neutral picked up from upstairs circuit :(
That could be dangerous with what is called a borrowed neutral. The two switches must be supplied from the same automatic disconnection device be it fuse, MCB, or RCBO. It is common to split up and down stairs lighting, where a line is borrowed from another switch this is not permitted. Although the line is borrowed it is called a borrowed neutral, the problem is some one can think a circuit is dead, but using the light switch can make it go live through the lamp being used, if the neutral is disconnected the neutral will become live.

When the system using two wires for two way lighting is used, then the lights can't be split up and down stairs. It's one or the other not both. However the rule book tells us we should ensure there is no danger from a single circuit tripping, as a result the normal method is to have lights and sockets on different RCD's for every room so if you were to use something which trips the RCD your not plunged into darkness. The standard method is to put upstairs sockets with down stairs lights and down stairs sockets with upstairs lights. With borrowed line you can't do that or it would become a borrowed neutral.

The cure is to use wireless switches, it means there is a battery which from time to time will need changing but it saves renewing the twin and earth with triple and earth. I have seen even electricians cheat and put both MCB's up and down stairs on the same RCD to stop the RCD tripping, this is still against the rules, you would need to re-combine up and down stairs lights having both on the same MCB.

Using twin and earth instead of triple and earth for two way lights also can upset hearing aids and other equipment because it transmits 50 Hz which other equipment can pick up. Today the practice is frowned on but not actually against the rules.
 
Thanks again Eric,

Yep, I'm aware of the potential risk of the landing light going live from either switch when somebody might think “upstairs” is off at the MCB.

I need to check but I'm pretty certain that is how it is/will be. Lighting wiring is original, only mid 1970's but not the original Fusebox/CU - the current CU was installed by the previous owners (well not by but whilst they had it).

Both Upstairs and Downstairs lights are on different MCB's though – I wish I'd twigged on the two way circuits earlier as running new Triple & Earth cabling for three 2-way lights is going to be rather difficult now – maybe not impossible but a royal pain and potentially take a less than direct route.

I'm not sure from your post though if even putting both circuits onto one MCB is OK ?

I guess in addition if I do replace with triple & earth or merge to one MCB I should confirm is this notifiable ?

With regard the external light that started all this off to some degree – I have found a fairly compact Wiska IP66 rated junction box locally that will hopefully suffice for a short time until I can pull those back to a internal junction box.

Thanks again for the input.


Rgds
FF
 

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