2nd outside light can someone check my logic..

[tonycoysh]

Physically doing it and wiring it I have no issue with and Zs, Vdrop etc are all fine. However I need a bit of clarification.

We live in a timber framed house, brick outside, dry lined inside. I’d run the cable from light fitting #1 back in the house, up the wall vertically from the switch through the joists to the corner of the house.
This is where I want to be checked. I’ve looked and without pulling out a brick outside (don’t want to if I haven’t got to) I’m going to struggle to get the cable through the header board into the void between the brick and the timber frame and down the gap to where we want light fitting #2. So instead I can run down the internal wall inside of the 150mm from the corner of the internal wall and then go external at the height required. (not that the 150mm applies because all is RCD protected as house is only 2 years old and obviously wired to 17[SUP]th[/SUP])

My question is: can anyone point out a blatantly obvious reason that I have missed for not doing this? E.g is it OK for me to go internal to external even though there will be no accessory/fitting on the wall in the cable’s vertical run.

Sorry if this doesn’t read well, my 1 year old is trying his best to help me type!

 

[Geoffsd]

What you suggest is alright.


However -

(not that the 150mm applies because all is RCD protected as house is only 2 years old and obviously wired to 17[SUP]th[/SUP])

That is not correct.

If not protected by methods of 522.6.101 (i to iv & vi) it can only be run in the safe zones ​and must be RCD protected.

 

[sjm]

As long as it's within 150mm of the corner, 150 mm of the ceiling, no problem. As Geoffsd says , it must be protected by an RCD if the cable is less than 50mm from the surface of the wall.

 

[Guitarist]

Any cable can be run in the 150mm "safe zone" provided, as Geoffsd has pointed out, that you protect it with an RCD. That said, to make it easier to get outside I would run it down the internal wall to a plated through-box then outside. That way, you can pull the cable down the trunking and straight out and always replace it if you ever need to.
Bear in mind it is always better to have external lights on their own mcb whenever possible.

 

[tonycoysh]

Thanks for comments/info Guys.

I appreciate that where possible external lights should be on a separate cb. However, am I right in believing that if there are no cable runs or external joints (other than in the light fitting) I.e it comes out of the wall and straight into the light fitting, then it is acceptable for it to be on the 'internal' light circuit cb? I'm sure I read it on here somewhere but as always I'm happy to stand corrected.

 

[Guitarist]

There is no rule against wiring an outside light into an internal light circuit as long as said light fitting is mounted on the building wall and not away from the building, ie lamp post. It is just good practice to have a separate circuit where possible. Obviously, if your outside light is a 500w floodlight then you may exceed circuit capabilities and you would have to separate it.