Double FCU??

r6deano · 23 Jan 2008

Hi,

Just found your forum seems really interesting!!

Was reading up on spuring fcu's, and wondered - can you buy a 'double' fcu? i.e. i want to spur two switches off of a socket in my kitchen, one for plinth lighting the other for under cabinet downlights. The switches are planned to be positioned next to each other, seems a shame to spur of two seperate ones if there is a way of buying a socket that can do two!!

Any help/advice much appreciated.

Thanks,

Dean

JohnD · 23 Jan 2008

no, but you can use a dual box which accepts two single accessories (if you want)

r6deano · 23 Jan 2008

Thanks, just been on B&Q quickly to see what a dual box looks like. Seems you can add two fcu fronts to it, correct me if I'm wrong.

Dean

r6deano · 23 Jan 2008

Thanks, just been on B&Q quickly to see what a dual box looks like. Seems you can add two fcu fronts to it, correct me if I'm wrong.

Dean

Might have just contradicted myself here - if I add two fcu fronts wont that make one of them a spur of the other?? Which I cant do?

JohnD · 23 Jan 2008

if it's on a ring, you put one leg into the RHS FCU, the other leg into the LHS FCU, and a short link to bridge the two FCUs together. then they become items on a ring. The ring just happens to be very short between them.

sparkieno1 · 23 Jan 2008

Could u not just spur from the ring to1 FCU and switch all the lights with this or do they definitely need to be switched separately?

r6deano · 23 Jan 2008

Ah good thinking John, thanks. So its a bit like a ring on a ring, but techically just an extension of one (one spur).

I thought of that one Sparkie but would prefer two seperate, thanks though.

daytona · 23 Jan 2008

JohnD said:
if it's on a ring, you put one leg into the RHS FCU, the other leg into the LHS FCU, and a short link to bridge the two FCUs together. then they become items on a ring. The ring just happens to be very short between them.

if your keeping the socket,you need to take one new cable to the left hand spur and new cable to the right hand spur (you now have two new cables in your socket plus the existing two )then put a link between the two spurs.then take one leg out of the socket and replace with one of your new cables.

make sure you dont use the live from one existing and the neutral from the other etc

you then crimp the remaining two together and take your loads out of the spurs to the equipment/ accesory.

ban-all-sheds · 24 Jan 2008

There seems to be some confusion.

r6 - if you could get a twin FCU, would you be connecting it as part of the ring, or to a single cable spurred from the socket?

r6deano · 24 Jan 2008

If I could get a double fcu, then I would connect it from my ring (i.e. off a socket) as a spur - as if you were adding another socket (an extension to the ring)

But I've never seen a double FCU.

Assuming this dual box is an option, I would attemp to -

Spur a cable off of an existing socket to the location of dual box
Appoint Live cable from this new wire to one side of dualbox
Appoint Neutral cable from this new wire to the OTHER side of the dualbox
Appoint Earth from new wire to earth point on dualbox (then bridge this across to earth point on other side of dualbox - if necessary)
Connect Live point from one side of dualbox to live point on other side of dual box using a new cable
Connect Neutral point from one side of dualbox to Neutral on other side of dualbox using a new cable

Thus forming a sort of ring on a ring, rather than a spur off of a spur.

If anyone can see a problem with this please advise!!

Wow, I think I've confused myself lol

If anyone can tell me how to post a picture I will put up a diagram.

Ta

dannyboi2003 · 24 Jan 2008

don't do that as its still a spur from a spur. I think things have got a little messy here so hows this for an idea.

Fit your dual box on the wall, take a spur to it and fit and un-switched FCU on one side fitted with a 5amp fuse, take a feed to the other half from the load side of the FCU and use a two gang lightswitch to give the split switching you require.

At the switch put all the neutrals together in a connector block, do the same for the earths, take the live to the common of one switch and loop is to the other, take the live from each of your lights and connect them to L1 of whichever switch you want them operated by.

Job done

If you need clarification let me know.

Dan

r6deano · 24 Jan 2008

Thanks Dan, sounds like a plan.

I'm gonna need to read up on whats what in terms of commons, L1's etc etc as the only experience I've had with that is replacing light fitments and switches, never wired a new one before.

That def sounds better though, nearer the time if I havent figured it out, you may see a new post on 'How do you fit a light switch' !!!!

Cheers!

andrew299 · 24 Jan 2008

could you not use a dual gang grid switch? It would make a neat solution.

r6deano · 24 Jan 2008

andrew299 said:
could you not use a dual gang grid switch? It would make a neat solution.

straight over my head andrew......proper newbie here im afraid hehe

i'll look one up see what it does/looks like/costs lol

ta

dannyboi2003 · 24 Jan 2008

r6deano said:
Thanks Dan, sounds like a plan.
I'm gonna need to read up on whats what in terms of commons, L1's etc etc as the only experience I've had with that is replacing light fitments and switches, never wired a new one before.
That def sounds better though, nearer the time if I havent figured it out, you may see a new post on 'How do you fit a light switch' !!!!
Cheers!

Hiya r6deano,

Sorry should have explained it better, common is the live feed to each switch and L1 is the switched live out of each one, some also have an L2 terminal but this is only used in two-way switching such as the light on your landing.

All the best
Dan

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Double FCU??

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