2 gang FCU?

[JohnnyG]

Is such a thing available (or even possible to do), as in 2 FCUs on a double surface box both fed from the same single supply?

Alternatively, if a dual surface box was used with 2 separate ones can you bridge the terminals to use one supply, safely?

 

[GaryMo]

You would have to go down the dual box route and have two separate FCU's.
If these are supplied from a spur off a ring final then be aware that you can only have one spur from any one point off a ring final but I don't see a problem with this arrangement as the maximum load you could consume on the spur is 2 x 13A (26A total) which is the same as a double socket outlet.

 

[EdwardCurrent]

Hello.
Yes. If wired correctly, then a 'dual' / 'barrier' box could be used with two 'fused spurs', from which, the circuits be independently isolated.

Ed

 

[sparkwright]

you could make one out of grid system.
a 4 gang plate the size of a double socket.
two 20A double pole switch modules.
and two 13A in-line fuse modules.

of course the biggest issue here would be wiring; making absolute sure they are NOT in the form of a spur off a spur from a typical 30/32 A ring circuit.

 

[GaryMo]

of course the biggest issue here would be wiring; making absolute sure they are NOT in the form of a spur off a spur from a typical 30/32 A ring circuit.

Why? It's still a maximum of 2 x 13A, same as a double socket.

Unless you can see a difference?

 

[sparkwright]

of course the biggest issue here would be wiring; making absolute sure they are NOT in the form of a spur off a spur from a typical 30/32 A ring circuit.

Why? It's still a maximum of 2 x 13A, same as a double socket.

Unless you can see a difference?

i meant if you made a 2 gang fcu you would have to link both sides of it. if his existing supply was a spur from a ring circuit you would be adding another spur to it.
if a 2 gang fcu was manufactured by an electrical manufacturer it would probably be made in the same way as a double socket, and spurring won't be of concern.
if his existing wiring (if he even has any) is directly on the ring, or some sort of acceptable radial circuit everything should be ok.
i think this is what you were asking about.

 

[GaryMo]

It wouldn't bother me much if it was this arrangement:

30/32 ring final > 2.5mm > FCU > 2.5mm link > FCU

In otherwords, a FCU fed from a ring final with another spurred off that.

It's still a total of 26A and as long as the cable used to supply the spur off a spur arrangement is equal or greater than with regards to current carrying capacity then I can't see a problem.

 

[sparkwright]

It wouldn't bother me much if it was this arrangement:

30/32 ring final > 2.5mm > FCU > 2.5mm link > FCU

In otherwords, a FCU fed from a ring final with another spurred off that.

It's still a total of 26A and as long as the cable used to supply the spur off a spur arrangement is equal or greater than with regards to current carrying capacity then I can't see a problem.

no, that would be fine if the first fcu is fed directly from the ring, and the second fcu is spurred from that.

but a spur can't feed the first fcu if the second fcu is spurred from that.

 

[JohnnyG]

It wouldn't bother me much if it was this arrangement:

30/32 ring final > 2.5mm > FCU > 2.5mm link > FCU

In otherwords, a FCU fed from a ring final with another spurred off that.

It's still a total of 26A and as long as the cable used to supply the spur off a spur arrangement is equal or greater than with regards to current carrying capacity then I can't see a problem.

That's the set up I was considering if I had to go the dual box route.
The current single FCU is the only spur off the ring final, 2.5mm and a 5a fuse and the new one will only be 3a with 2.5mm so total load won't be an issue.
It was just the thought that it might be classed as another spur that had me thinking even though it's essentially the same as a double 13a socket outlet, as mentioned.
Should I drill through the middle wall of the dual box and link the terminals that way?

 

[JohnnyG]

no, that would be fine if the first fcu is fed directly from the ring, and the second fcu is spurred from that.

but a spur can't feed the first fcu if the second fcu is spurred from that.

Sorry, I missed this.
That's what I initially thought

 

[sparkwright]

usually you can knock out the middle wall of the box with a hammer and screwdriver.

 

[GaryMo]

no, that would be fine if the first fcu is fed directly from the ring, and the second fcu is spurred from that.

but a spur can't feed the first fcu if the second fcu is spurred from that.

Why?

It's still 2 x 13A, 26A in total. Same as a double socket.

 

[sparkwright]

assuming the circuit is a 30/32 A ring circuit wired in 2.5 mm cable and the wiring you wish to connect onto is a spur ie one cable;

i would connect your supply cable to the supply side of an unswitched fused spur unit at 13A.
from the load side run a short piece of 2.5 to the supply side of a switched fused spur unit.
also from the supply side of that switched fused spur unit run a short piece of 2.5 to the supply side of a second switched fused spur unit.

connect loads accordingly to the two switched fused spur units.

any way you can extend the ring to supply the sw f spurs?

 

[Adam_151]

It's still 2 x 13A, 26A in total. Same as a double socket.

A double socket outlet is rated at 13A *total* , and diversity sees that folk never normally go over that, save for a few slightly browned ones behing the washer and dryer...

As spurs are normally used to feed fixed equipment then I would consider such an arrangement as quite likely to overload (unless the fixed equip is such as alarm panels, etc, but then, why would you have them switched?)

 

[GaryMo]

But what's wrong with spuring to one FCU then linking from the feed terminals to a second FCU?