Adding an exterior light

[lizzyb]

Hi there.
Hope you can help with this one !
I have just installed an exterior PIR / dusk-dawn light outside the front door.The only easy electrical source I have would be from the light switch in the interior hall. I have replaced the single gang switch with a 2 gang and intended to use the free gang for the exterior light. Having tried a few connection combinations, I thought I had it sorted until the hall light started coming on at a reduced brightness (dusk ?! ) after switching it on and (later) off !
Have I got it very wrong, or can I blame the light ??!

Existing wiring ( original switch ) Red to L1, Black to comm, earth to earth
(ashes to ashes etc.)
Exterior light L N & E.

All help gratefully received.

lizzyb.

p.s. It's great to know that there are still people out there willing to help and share their knowledge. Thanks. ( not kissing a-- .Well not much. )

 

[securespark]

It is probably dim because it is wired in series to another lamp.

You don't generally find neutrals in switch boxes, and that is what you need. Neutrals are generally only found in the ceiling positions.

 

[Steve]

yeah, the black at that switch is a LIVE. there is no neutral there.

Think what would happen if you had a live and a neutral connected to a switch, and flicked the switch on . . . . bang. what you have is live and switched live. as secure says, you need to get a neutral from the ceiling.

This could be done by replacing the switch drop wire with 3 core and earth - then have live, switched live and neutral at this switch, just carry the live and neutral (and earth) to this new light of yours.

 

[lizzyb]

Hi guys,

Thanks for that.

Securespark, the hall light is bright (i.e.normal ) when you switch it on, but then after you switch it off if comes back on again... only dimmer ! and the exterior light also comes on but brighter !

Agree that the black wire is not a neutral. So are you saying only way to wire it is to drop a new cable from the ceiling rose ? If so,this may not be that easy (well for me anyway) because the ceilings of this ground floor flat are concrete and have all the wiring buried in conduit.

Any further thoughts...apart from.. give it up ?

Thanks again

 

[breezer]

would have been nice if you had mentioned the conduit.

that makes it easier, since conduit you can add another single core, but then again its not realy a diy thing.

how about wire t in via an fcu which is fed from a socket?

 

[Dippy]

Hi guys,

Thanks for that.

Securespark, the hall light is bright (i.e.normal ) when you switch it on, but then after you switch it off if comes back on again... only dimmer ! and the exterior light also comes on but brighter !

You have the PIR lamp wired in parallel with the switch, which is then in turn in series with the hall light, which has a return to neutral. So when the switch is on, the PIR is shorted and will be off, and the hall light will be fully on. But when the switch is off, the PIR will get current, activating it and turning on the exterior light (as it is designed to do). But this is in series with the hall light, so both will flow less current and therefore be less bright than if they were properly connected.

If the external light is brighter it is just because it is higher wattage.