Outside Light

[wireways]

I want to fit a new outside light to my house by taking a feed from an existing lighting circuit but I've been told that it is no longer permitted to do this without RCD protection to the circuit. I can't find any reference to this anywhere. Is it true?

 

[Steve]

IIRC, outside lights dont need RCD protection. Only power points require protection. Who told you this nonsense?

I think the real reason you were told you shouldn't do as you say is because outside lights can consume as much as 500w each, and when your lighting circuit can only provide a total of 1300w, this is not good.

Its still allowed though.

 

[Adam_151]

the only thing I can add to what crafty says, is that the disconnect time for an outside light is 0.4 as opposed to 5 seconds for most other lights and fixed equipment (because you could be touching the light while standing outside the equipotential zone), if you have circuit breakers, its no problem, if you acheive 5 sec disconnection, you acheive 0.4 (once you hit the magnetic trip point, it clears the fault in 0.1 or faster) the problem might come if you happen to have fuses, an RCD can be a fail safe, that will clear the fault incase a DIYer installs a light without measuring ELFI and the ELFI is out of spec, which is why I presume its sometimes recommended to rcd them

also if you install a 5A fcu on a ring, unless you have a very long cable between FCU and light, you will acheive 0.4sec (i'm assuming of course that the ring is properly designed and the EFLI at the postion of the FCU can clear a 30A 3036 in 0.4), if you put your light on the end of light circuit protected by a 5A re-wireable at the orgin, then its possible that it might not meet 0.4 disconnection