Switch/split electrics

[Zudecke]

Hi

We want to install a low powered PIR sensing light to the entrance/porch of our property (external) .

The closed electrically powered item is the light in our actual entrance (internal).

Electrician has said there's either the proper way, which involves going directly to the main switch, which requires a new switch slot and additional cables and cabling, or the dirty method, which involves splitting the signal from the internal hallway lighting - thus one mains switch effectively powering both these lights.

Wanted to know if that sits right with anyone know knows about these things, or if there is serious risk involved?

Many thanks

Z

[ericmark]

It is normal to switch neutrals with outside lighting as well as line, so any water ingress will not stop you using internal lights once outside light is switched off. But since it is only for emergency use should water get in outside light the switch does not need to be easy to access, so butted up to ceiling is OK as I would assume normally left switched on, having said that my outside lights are normally switched off, and the switch does not switch neutral, I would assume fitted when house built in 1980's.

So my outside lights were fitted before RCD's were fitted, today all new circuits are RCD protected, so the risks or fire and shock are reduced, but risk of power loss is increased, with my house every circuit has its own RCBO which is a MCB and RCD combined, so if I have water ingress it only affects one circuit, many houses have had RCD protection added on the cheap, with multi circuits protected by the same RCD, so in my case if water did trip the lighting, the rechargeable torch at top of stairs would still work to light my way, as would all standard lamps and table lamps. But this is not always the case.

Other than the flat roof leaking and tripping one circuit in the flat under the house I have not lost power in this house due to water ingress, and when I did in the flat it was a small problem as only one circuit lost, with last house with just two RCD's the trip cost a freezer full of food, which is why I paid the extra to have all RCBO protection in this house, one freezer full of food is less than the extra paid to have all RCBO protection.

[kellys_eye]

The 'dirty' way isn't bad or illegal - it's perfectly safe but avoids the extra expense.

[Zudecke]

Thank you both for the help responses. Good to validate these things :).

Many thanks

Z