Spuring from a spur...

[antinode]

The mains supply to my alarm panel is a spur taken from the ring main (fed via a 32 A MCB) using 2.5 T&E through an FCU containing a 3 amp fuse. The total length of cable from the junction box to the FCU is about 3.5 meters. I want to add a 1 amp Elmdene power supply to my system. Is it OK to take another spur from the FCU supplying my alarm panel? I know your not supposed to spur off a spur, but with such a neglegible load on the spur at present, is it OK? I will be adding another FCU for the PSU, but if I can help it, I'd rather not go to the trouble of extending the ring up into my attic.

Thanks!

[Guest IM_Alarms]

You can come off the load side of the first spur and add another spur as it is for the same system after all.

It is possible to spur off more than once from a fused spur.

[Service Engineer]

Can't you just come off the existing Spur so its feeding both the Alarm & PSU, rather than fit another seperate Spur..?

[Deltaseven]

Can't you just come off the existing Spur so its feeding both the Alarm & PSU, rather than fit another seperate Spur..?

53324[/snapback]

I guess you could, but we never do - we always insist that each mains powered device can be individually isolated. Not sure if that is a requirement or just a preference. But it does mean that our sparky does OK for himself...

[whistle]

The way i would do it is come out of the incoming side of the panel out to the PSU asuming thay are next to each other. if not fit another fuse spur.

[mcelec]

you will be fine to spur off for another fused spur in these circumstances based on the load you mentioned and assuming the cable run is not going to be exceptionally long

[jb-eye]

you will be fine to spur off for another fused spur in these circumstances based on the load you mentioned and assuming the cable run is not going to be exceptionally long

53367[/snapback]

Carefull. We are allowed only one spur off each point of the ring. Now if i wired a double power point from one point of the ring my maximum conectable load will be 26 amps (2x13a plugs) If i was to install 2 x FCU same load but this does not comply with regs. But if i install 1 x FCU and from the load side of this unit i can in theory wire and fix as many FCU as i like up to the maximum anticipated load of 13amp

Jef

[Guest]

Carefull. We are allowed only one spur off each point of the ring. Now if i wired a double power point from one point of the ring my maximum conectable load will be 26 amps (2x13a plugs) If i was to install 2 x FCU same load but this does not comply with regs.

53375[/snapback]

Not having a current copy of the regs to hand I'm not sure of the numbers but you can spur of a spur under certain circumstances where you have designed the maximum load to be acceptable for the equipment used.

Personally, I'd prefer to extend the ring or replace the junction box with a 13A spur so you can connect multiple spurs downstream of it.

[Guest IM_Alarms]

you can only spur off once from each point of a ring circuit (a point is an existing socket/ spur or a junction box). You can add a fused spur and then come off the load side as many times as you like up to the rated 13A.

Just a note JB:- a double socket outlet will not take 26A, if you look at the back of one it will have 'rated at 13A' this mean the total connected load i.e. both outlets. Many people make that mistake and I only know because i've come across many cheap socket outlets that have started to burn up when connected to say,' dishwasher and washing machine' etc.

[antinode]

So I'm alright if I connect the power supply to the load side of the FCU that's already there? That makes things easier. I think I'll stick another FCU on for the PSU anyway, just cos I'm like that