fused spur

[SALPET]

i have taken a fused spur from the ring main. which is fused down to power a light under the stairs. from that fused spur can i use 2.5 cable to another fused spur and fuse it down, then 1.5 cable to supply an outside light.

 

[JohnW2]

i have taken a fused spur from the ring main. which is fused down to power a light under the stairs. from that fused spur can i use 2.5 cable to another fused spur and fuse it down, then 1.5 cable to supply an outside light.

You don't actually need to fuse down again for the second run, since the fuse for the first one (which can't be greater than 13A, and is probably smaller) would be adequate to protect the 1.5mm² cable.

However, as I'm sure someone will tell you if I don't, whilst the first spur is not notifible to your LABC, installing an outside light is. You might also find some people commenting on the acceptability/advisability of running lights off a power circuit, but I personally would not be too concerned.

Kind Regards, John

 

[PrenticeBoyofDerry]

i have taken a fused spur from the ring main. which is fused down to power a light under the stairs. from that fused spur can i use 2.5 cable to another fused spur and fuse it down, then 1.5 cable to supply an outside light.

You could use 1.5mm t&e or even 1.0mm t&e, without down fusing.
What rating is the existing FCU?

 

[SALPET]

sorry my mistake,,, the fused spur is a switch spur, should that make a difference or carry on witht the 2.5m to the next fused switch spur and then 1.5 to the light????????

i think it was a 3amp fuse for the light,

cheers guys for info

 

[JohnW2]

sorry my mistake,,, the fused spur is a switch spur, should that make a difference or carry on witht the 2.5m to the next fused switch spur and then 1.5 to the light???????? i think it was a 3amp fuse for the light,

I'm not totally sure what your saying. If there is a fuse (anything up to 13A, so 3A would be fine) in the spur to the indoor light, then you can just go straight down to 1.5mm cable from the output of the fused connection unit (FCU) without having to do any further fusing - regardless of whether the FCU is switched or not.

However, if you're saying that you are using a switched FCU to switch the under-stairs light on and off, then you've obviously got a bit of a problem, since the outside light you plan to add then wouldn't work whilst the under-stairs light was switched off if you fed it from the output of the FCU. In that case you would, indeed, need a second FCU for the outside light, but that would have to be fed directly from the ring circuit itself, not from (either the input or output of) the first FCU.

Kind Regards, John

 

[PrenticeBoyofDerry]

The problem you will have is when the switch from the existing S/FCU is open, nothing down circuit will be powered if taken from load side. So you would need to take power from supply side of S/FCU to next in line and so on.
I would be tempted to install a FCU from the original source (RFC) down fuse a sub circuit to 5A, then take your power from there using standard 5A switches to operate your lights. You can then use for the circuit after the 5A FCU, 1.0mm t&e.

 

[ericmark]

In theroy you can use up to a 16A supply for lighting unless something else restricts one. Normally since the ceiling rose is rated 5A that means in real terms 5A max.

In theroy every light bulb should have a built in fuse in case of ionisation when the bulb blows so although most BA22d bulb holders are rated 2A max it still OK. However bitter experience Ikea sell lamps without the built in fuse and I am sure many other do too. So when the bulb blows you end up changing the bulb holder as well. So I would always fuse to 3A with a FCU. I say 3A rather than 5A only because 3A is the standard size so easier to get.

As to Part P that's your problem I am uncertain as to if with no exterior connection it is required or not. So with a pre-wired lamp and the connection is made in the house but not kitchen or bathroom then may not be required but it's up to you to check on that.

 

[SALPET]

so i could change the current s/fcu spur to a fcu spur, and then from the fcu wire 1.5m to either a switch for the outside light or straight to the outside light.

the indoor can still be switched on and off from the light itself so that wont be a problem.

sorry i just need to make sure i got in my own mind.

 

[PrenticeBoyofDerry]

So your stair light has a switched FCU protecting the additional circuit and then a further functional switch for the light?
If so, you can keep it as it is if you wished, no need to change from switched to un-switched.
1.0mm t&e will carry a maximum current of 16A, so you can in theory use any t&e cable from 1.0mm or greater.

 

[OwainDIYer]

AIUI if the light is fitted on the exterior house wall and the cable runs straight through the wall to the light then it's not notifiable.

 

[JohnW2]

AIUI if the light is fitted on the exterior house wall and the cable runs straight through the wall to the light then it's not notifiable.

As you may know, that's a very controversial issue which has been very rigorously debated many times, incluing in the current thread entiteld 'Holiday Snaps', or something like that.

The fact is that 'Approved Document P' does, indeed, suggest that what you say is true - and many people seem to believe that it is true (presumably because of that document, and books which have 'copied from it'). However, that is just a (seemingly not very well written) 'guidance' document, and the 'actual law' (Schedule 4 of the Building Regs) appears very clear in saying that installation of any 'outdoor lighting installation' is notifiable.

Kind Regards,John

 

[JohnW2]

In theroy you can use up to a 16A supply for lighting unless something else restricts one. Normally since the ceiling rose is rated 5A that means in real terms 5A max.

Yes, fusing down to 5A or 3A would be preferable, for that reason (and it sounds as if the OP has already done that). However, what I was actually thinking of was your recently expressed opinion that running power sockets off a lighting circuit violated the regs' requirement for 'circuit separation' - in which case I was wondering whether you would feel the same 'the other way around' (and, if not, why not?) - although, as I wrote to teh OP, I wouldn't personally be concerned (it happens in many a garage/shed, for starters!).

As to Part P that's your problem I am uncertain as to if with no exterior connection it is required or not. So with a pre-wired lamp and the connection is made in the house but not kitchen or bathroom then may not be required but it's up to you to check on that.

See my comments above, and the thread I refer to there.

Kind Regards, John

 

[PrenticeBoyofDerry]

Yes a discussion made many times, with regards to outdoor lighting equipment.
Schedule 4 indicates the work is notifiable but guides made and approved by the IEE contradicts this, by qualifying otherwise "if light is fixed to wall of dwelling and no external connections (with exclusions of cables routed through special location and kitchens)".

Who is right, well schedule 4 is the legal requirements and the guides are the guides to how to comply to schedule 4. In a court of law you will have to abide be the statuary document, rather than the guide.
Even though I have connected my local council regarding schedule 4 at certain flaws within it's composition and the person I was in contact with, did accepted there were errors within it and these were to be amended in 2013.

Please note I can not validate the claims of the person I spoke to at the local council, but this was their area of supervision.

 

[JohnW2]

Yes a discussion made many times, with regards to outdoor lighting equipment. ... Schedule 4 indicates the work is notifiable but guides made and approved by the IEE contradicts this, by qualifying otherwise "if light is fixed to wall of dwelling and no external connections (with exclusions of cables routed through special location and kitchens)". Who is right, well schedule 4 is the legal requirements and the guides are the guides to how to comply to schedule 4. In a court of law you will have to abide be the statuary document, rather than the guide.

Quite so. Actually, it's not so much "guides made and approved by the IEE (I presume you mean IET)" which are the issue- but, rather, Approved Document P which is issued by the Office of the Deputy Prime Minister and is meant to repesent guidance on compliance with the reqirements of the Statutory Instrument. The fact that there are things in, say, the OSG. which are not in BS7671 itself is another issue - but neither of those represent 'law', and neither address notifiability.

Even though I have connected my local council regarding schedule 4 at certain flaws within it's composition and the person I was in contact with, did accepted there were errors within it and these were to be amended in 2013.

Interesting. The contradiction/inconsistency is clearly not acceptable. Whether it is Schedule 4, Approved Document P or both which need amendment obviously depends on the intentions of the authors. There are certainly a number of aspects of Schedule 4 which, if I were 'them', I would probably want to revise/clarify but, since "I am not them" (and am nont a self-certifying electrician) I'm not so keen that they do! We'll see!

Kind Regards, John

 

[SaladFingers]

Fused connection unit.

'Spur', is a method of wiring and not a object or wiring accessory.