FCU on a lighting circuit

[DPG]

But he shouldn't be asking you to do it. And you shouldn't be doing it if you aren't competent to do it. Daz

 

[Spoon]

So you are saying that the outside light are already wired in and the electrician has asked you to hack into the circuit and fit a FCU?
I wouldn't bother. Just keep the outside lights as they are.

 

[amckay]

Everything else has been fine and zero problems. it's just this FCU that has caused problems as he's asked us to do it last minute and not really explained why.. the lights are already wired into the circuit and under floorboards etc so the hassle of digging it out now to put on its own ring is a pain. we originally wanted the outside lights on their own mcb but he said there was no need.. now i'm getting the feeling that there is a need, otherwise we wouldn't need to isolate them..
he's been perfectly happy with everything else that i've wired in..

ultimately it would have been difficult to have someone come in and rewire because the house has needed building up from nothing.. there is only one mcb for the whole house as it stood.. we've had to move in and so there was no way we could really get someone in to rewire it.. like i said, it's just this bit that has had me thrown as it's ended up a bit of a contradiction.

Carlos.. i see you're intent on trolling this thread without actually contributing anything of use.. you're clearly a self aggrandised twit with nothing better to do.. go and make yourself useful- electrocute yourself..

You live and learn. Nothing substitutes a good well thought design with an understanding and competent installer!

 

[malcolmsanford]

Do not feed the troll

 

[trev]

Do not feed the troll

MALCOLM!!!!!!!!
Welcome back mate, I was just about to start athread asking if anyone had heard from you recently.
How the hell are you?

 

[malcolmsanford]

Trev!!!!! How the devil are you? I'm still hanging in there mate back in the UK and sort of semi retired but keeping my hand in. How are you ?

 

[trev]

I'm very well mate, busy but could be busier but the bills are paid there's grub in our bellys and beer in the fridge so it must be pretty much ok.
So no more foreign excursions for you?

 

[Octopus]

basically our outside lights are wired into the lighting circuit and all have individual switches (not FCUs). Our electrician came to wire things in last week and said that as they are PIR they need to be on FCUs. We are replacing the lights with non PIR lights anyway (10W LEDs) but he said that to future proof them (in case we want PIRs in the future) and in order to isolate them, we have to have each one on a FCU.

We have put non maintained junction boxes in the wall spaces so only the power cable to the light goes outside. Without the FCU these are wired the same as any other junction box or ceiling rose, i,e, line in and out, switched live and comm from the switch and the neutral and live from the light. However, I don't know where I need to put the FCU in- is it before or after the switch.. I assume before, so that all power in is cut off.

if so, do I need 3core to connect it to the switch so that comm/ live/ neutral connections are maintained, or am I missing something? I get what I need to do if I was connecting it as a spur from a socket. I think the whole 'double switching' element is the bit that's confusing me..

@Carlos- you're really not being any more helpful. If you have nothing useful to say, go and bother somebody else.
@Spon- thank you. As to why we need FCUs, who knows. Like I said, he has said futureproofing..

Can you expand on this as it doesn't make sense.

 

[Deleted member 72666]

Can you expand on this as it doesn't make sense.

I took that to mean 'maintenance free'.

 

[Octopus]

I took that to mean 'maintenance free'.

I took it that he may have placed JB's in the cavity!

 

[telectrix]

Trev!!!!! How the devil are you? I'm still hanging in there mate back in the UK and sort of semi retired but keeping my hand in. How are you ?

malc!!!! welcome back.

 

[Richard Burns]

(Hi Malcolm)

Bel

I can see no reason for an FCU in this situation. Fusing down the outside light (say to 3A from 6A) will have very little effect, I cannot think of any lights that have needed limiting on the current they could take (and if they did then they should be internally fused).
The switching effect of the FCU could be to have double pole switching (though the FCU may not be double pole), this could be achieved more easily by swapping the light switch for a double pole switch.
The switching effect of the FCU could be to have an overall off situation, so that the PIR was un-powered, perhaps for maintenance, but really you could just switch off the lighting circuit. This FCU could also be intended as a PIR off and use the light switch as a manual override ON, whilst the PIR is powered, but this could be achieved without the fuse and just use a double gang switch (double pole if desired for the PIR off) in place of the existing single gang.

From your diagram, unless the output from the maintenance free wago box had a three core cable to the light PL, SL, N then none of the override functions would be possible, so there would be no need for the permanent line to go to the Wagobox, since it is inaccessible later modifications would need to rip things apart anyway.

Leave the FCU out and change the single gang switch to a double gang if required (grid switches if other functions needed, Click grid switches if you need a fuse as well)