Outside Light on a switch with separate FCU for PIR

Irish Mick · Jul 20, 2014

Apologies if this scenario has already been posted but I am unable to find it.

Came across a the above circuit yesterday as it was tripping an RCD. Feed seems to be coming from a Porch light. This is controlled by a switch in the hallway. Feed comes down to the back of the FCU near the CU and then goes to the PIR via connector blocks in the back box of the fcu. FCU has its feed from the CU direct with its load being the outside light. Seems they want the hallway switch to control the lights independently with the PIR also switching them independently. Can anybody see an issue with the wiring as I cannot get my head around what has been done. The PIR has 3 terminations in a connector block.

UNG · Jul 20, 2014

Probably easier to understand if you post a diagram of what you have and a few pictures

Octopus · Jul 20, 2014

Sounds like the FCU and the lights could be on seperate RCD's!

What do you mean "came across" - is this your own house?

Irish Mick · Jul 20, 2014

UNG said:
Probably easier to understand if you post a diagram of what you have and a few pictures

Hi. Thanks for the quick response. Was actually thinking on the way home in the van......'Heck, I should have taken pics to mull this one over.' Lesson learnt.

Irish Mick · Jul 20, 2014

Murdoch said:
Sounds like the FCU and the lights could be on seperate RCD's!

What do you mean "came across" - is this your own house?

No, was a call out. Not sure who installed it but it had been isolated to stop tripping.... Moved FCU to the same RCD as the downstairs lighting and this stopped the tripping. But, the porch light was constant and the hallway switch would not control it. Solved one problem only to find another. Thinking the wiring in the fcu back box may need altering.

Octopus · Jul 20, 2014

Irish Mick said:
No, was a call out. Not sure who installed it but it had been isolated to stop tripping.... Moved FCU to the same RCD as the downstairs lighting and this stopped the tripping. But, the porch light was constant and the hallway switch would not control it. Solved one problem only to find another. Thinking the wiring in the fcu back box may need altering.

You are tagged as a DIY member!

Richard Burns · Jul 20, 2014

Sounds like (although "connector block in the back of the FCU" does not really tell us much) they intended to do this

[ElectriciansForums.net] Outside Light on a switch with separate FCU for PIR

but the circuits should all be part of the same circuit not separate circuits.

Irish Mick · Jul 20, 2014

Murdoch said:
You are tagged as a DIY member!

I know I am and I don't know how to change it.

trev · Jul 20, 2014

Contact a mod re the membership mate.
Sounds to me like someone has tried (badly) to have the PIR and the light able to be switched seperately. No idea why they'd do that though. Much easier to just rig it with a switched override of the PIR.

Irish Mick · Jul 20, 2014

trev said:
Contact a mod re the membership mate.
Sounds to me like someone has tried (badly) to have the PIR and the light able to be switched seperately. No idea why they'd do that though. Much easier to just rig it with a switched override of the PIR.

Thanks for the help. Will go back to the job and suggest I re-do that part of it. Thanks again.