outdoor lighting on normal switch if on own mcb? +

[trevw]

Hi,

I've got a few questions I couldn't find answers to ..
1) for a high wall light by a back door where the cable will be run down to the light from within the soffit, does this still need to be SWA cable? Also I wanted to switch it from a normal 3 gang switch by the door which would ideally also be switching an internal light. Can I do this by running a seperate outside light power cable from an mcb?

2) I was planning to run power to my garage using two 2.5 twin and earth from an mcb terminating in a weather proof junction box on the wall outside then running SWA from there to the garage, having read a bit more on the forum this doesn't seem the normal way to do it, is it a 'bad' way or just unusual?

3) in a combination of the above, I was also hoping to have lights around/in my patio and hoped to run power to a normal switch (from a dedicated outside lighting mcb) and then the switched supply to the lights to another weatherproof box on the exterior of the house which I could at a later date connect whatever I chose to (again is this against regs, just bad practice or fine?)

I haven't talked these over with my electrician yet as he is on holiday but hoped to get the cables laid in by the time he got back so he can inspect and I can get the plasterer in, so any advice would be great..

thanks

Trev
(did search the forum but couldn't find anything simlar, thanks)

 

[davy_owen_88]

1) for a high wall light by a back door where the cable will be run down to the light from within the soffit, does this still need to be SWA cable? Also I wanted to switch it from a normal 3 gang switch by the door which would ideally also be switching an internal light. Can I do this by running a seperate outside light power cable from an mcb?

No, but you can't use standard twin and earth either unless it is protected from direct sunlight (in conduit).

You can run a new cable from a spare 6A MCB.

2) I was planning to run power to my garage using two 2.5 twin and earth from an mcb terminating in a weather proof junction box on the wall outside then running SWA from there to the garage, having read a bit more on the forum this doesn't seem the normal way to do it, is it a 'bad' way or just unusual?

It is a bad way of doing it. Run suitably sized SWA to a metal box near to your consumer unit and fit equally sized twin and earth from the box to the CU.

3) in a combination of the above, I was also hoping to have lights around/in my patio and hoped to run power to a normal switch (from a dedicated outside lighting mcb) and then the switched supply to the lights to another weatherproof box on the exterior of the house which I could at a later date connect whatever I chose to (again is this against regs, just bad practice or fine?)

You want to avoid as many joints as possible - just more things to go wrong.

Davy

P.S I really wouldn't start running cables without your electricians advice and say so. They have to be run in certain zones and if you do it wrong it'll take him longer than if he had just done it himself.

 

[trevw]

thanks for the info Davy, am relatively comfortable with indoor electrics and have advice from people who have done a lot of house wiring, the electrician has seen all the internal wiring and is happy. I just (as you may have guessed, have NO idea when it comes to external stuff and how to bridge it to the internal wiring.

so for 1) I can run twin and earth from 6A mcb to switch, then the same to light if in conduit where exposed..

for 2) calculate the SWA needed for lighting + decent power tools (pillar drills, saw benches etc.) + hand tools over a ~15m run and connect as you say

for 3, I'm not sure how to proceed, I've no idea what garden/patio lighting we will want (tho we will want some) this may be a mix of walk over and post/bulkhead/spot lighting (maybe mixed voltages?) . I was hoping to have somewhere I could switch this all from by the back door like a 'normal light' feeding a junction box that I could hook into once we have a garden (rather than a mud pit )hence my slightly naive method above. Is there a good way of doing this or do I have to work out what we are doing with lighting 'now'?

cheers for the help

Trev

 

[davy_owen_88]

so for 1) I can run twin and earth from 6A mcb to switch, then the same to light if in conduit where exposed..

Yes, 1.5mm^" twin and earth from MCB to the light switch. Then using a connector block and some green+yellow sleeving take a feed from the switch to the outdoor light (run in conduit or going straight through the wall into the back of the light).

for 2) calculate the SWA needed for lighting + decent power tools (pillar drills, saw benches etc.) + hand tools over a ~15m run and connect as you say

Yes, I doubt you'll require much power for hand tools though It's always better to go one size up when you run SWA just to be sure you won't need to rip it up and lay new when you buy a more powerful table saw etc...

for 3, I'm not sure how to proceed, I've no idea what garden/patio lighting we will want (tho we will want some) this may be a mix of walk over and post/bulkhead/spot lighting (maybe mixed voltages?) . I was hoping to have somewhere I could switch this all from by the back door like a 'normal light' feeding a junction box that I could hook into once we have a garden (rather than a mud pit )hence my slightly naive method above. Is there a good way of doing this or do I have to work out what we are doing with lighting 'now'?

There's no rule saying you have to have all the electric work done at once. When you decide what you want just call the electrician back. And I'm not saying you can't have an outdoor joint box but it would be better if you planned what you wanted first and used the most efficient way of doing it (so as to minimise problem areas later).

Davy