Power lights in loft from lighting circuit help please

I plan on finding the last light in loop that should have only 2 cables into it. From there I take 1.5mm t&e joined into that light fitting to a fused switch I plan on putting 3amp fuse max into that and the flex from the light unit would be permanently fixed into that switch. The light unit is metal it runs 4x t5 tubes equal to 4x 54w tubes 0.96amps. I run cable from lighting fixture to fused switch then the light is fixed into the switch. Is this all sound correct have I missed anything. The light is free hanging on adjustable hangers.
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On Thu, 12 Oct 2017 12:14:02 GMT, Yam man
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The FCU seems unnecessary to me, why not use an ordinary switch?
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Graham.
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Graham. wrote:

And there is no need to find the end of the line. Picking up unswitched power from the nearest convenient lighting JB or ceiling rose should be fine. Dont forget to take an earth to the light fitting as well.
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replying to Bob Minchin, Yam man wrote: Thanks for input guys. So I've found a lighting cable that reads live on voltage tester pen I can turn off breaker to lights then cut that cable wire both ends into a new 4way 20 amp jb. Join my switch into that loop then from switch I join on my light? Is that correct? I have basic knowledge and awareness of electrics but I'm a mechanic not a sparky so apologies if I'm not very quick on uptake we all learn new sometime. I'm not sure about where the earth come from or to for the light fitting? It has a cable and 3pin usual plug on I plan on cutting it off and it should have earth in that is that not sufficient? Thanks again for all and any help.
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On Thu, 12 Oct 2017 20:44:02 GMT, Yam man
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Odd that it was supplied with a plug, but that seems OK. Just for the avoidance of doubt, this lighting circuit is protected by a 6 amp breaker, yes?
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replying to Graham., Yam man wrote: Hi thanks for reply graham yes the lighting circuit is protected by 6amp breaker. It has 8 lights upstairs and all seem to have 3 wires into each ceiling rose/light fitting. All CFL bulbs apart from 1 that has 5 gu10 bulbs on the light bar in daughters room. That will be changed over next few weeks to usual CFL x2. That's my lighting sorted out now then. Thanks for help. Next project is getting 2 double switched sockets up there. Any help advise greatly appreciated guys
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On 12/10/2017 21:44, Yam man wrote:

Here is how you normally do "loop in" wiring with junction boxes or at a switch location:
http://wiki.diyfaq.org.uk/index.php/House_Wiring_for_Beginners#Other_Wiring_Options

Yup the earth in its flex will be adequate.
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replying to John Rumm, Yam man wrote:

Thanks for that John great help. It will take me awhile to get to grips with as I said previously I'm a grease monkey only normally deal with 12v electrics. I'm not stupid I'm aware that this voltage is extreme to what I'm used to but with help from you guys I'm sure I can obtain the result I need.
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On 13/10/2017 12:44, Yam man wrote:

Yup, take it steady, read some of the electrical articles in the wiki, and ask questions if you are not sure, and you will be fine.
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EEk, dont think you should put sockets on a lighting circuit, wire's too th in, somebody might plug in a heater. And legally you'd need council buildin g control.
Why not use an extension lead off of an existing 15 or 30 amp socket?
I think its still legally an extension lead if you have to remove the plug before threading it through holes in floors and ceilings and walls, make su re its a big fat wire if it goes a long way and may have heaters, kettles, elec tools etc off it at some time in the future. And replace the plug wit h a 13 amp fuse, or10 amp, or 3.
If you blow the lights circuit fuse all the lights will go off, so get a ba ttery backup light too!
[george]
Yam man     wrote: 12:44 PM (3 hours ago) replying to Graham., Yam man wrote: Hi thanks for reply graham yes the lighting circuit is protected by 6amp breaker. xxx Next project is getting 2 double switched sockets up there. Any help advise grea tly appreciated guys
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On 13/10/2017 16:34, DICEGEORGE wrote:

So long as you label them as only being suitable for loads under (say) 3A then you are ok.
The wire will be adequately protected against fault and overload by the MCB, so that is ok.

No you don't. That would only be for a job classed as "notifiable". That does not include extending existing circuits, or work in a loft.
(it would include changing the main CU or adding completely new circuits)
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replying to John Rumm, Yam man wrote: Sorry not been clear in last post. The Fcu will have only 3amp fuse in for the described light that's goin to be removed if I ever remove the light from the lighting curcuit. I wouldn't take double sockets from lighting as I know it's a no no unless amped down to 3-5 amp max? But I plan on taking cable from the rear of our socket on the landing down inside wall and under floorboards run of around 6ft then up the inside of cupboard halfway up wall into 13amp sfu then cable into loft which is run of around 15-18ft clipping it directly to the wall in cupboard and into loft then a double switched 13 amp socket from which I want to future proof and add a 2nd double socket. (Never no might hide away from the wife and need home cinema kit installed) :) that's the plan for the power sockets does that all sound ok? Is there any rule reason not to use 4mm t&e to spur from socket? I'm using 1.5mm for the lighting curcuit. Does this all sound ok or am I seriously missing something? Thanks for help again guys
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On 13/10/2017 23:44, Yam man wrote:

Its not uncommon for example to add some sockets in a loft to a lighting circuit to allow things life aerial amps to to be powered.

If it were just one double socket, then you could do without the FCU (i.e. it would count as an unfused spur). Its only when you add more sockets you need the extra fuse.

No rule, but also little point usually. If its a 13A fused spur, you wont need that size cable for the extra current carrying capacity (2.5mm^2 CSA is rated at 27A when lipped direct to a surface).
http://wiki.diyfaq.org.uk/index.php/Cables#Cable_Sizes
Also its harder to work with the thicker cable, and you may find it difficult getting it into the terminals on the socket if it already has 2 x 2.5mm^2 in each one.

Lighting circuits are typically wired in 1.0mm^2 or 1.5mm^2 so that is fine... (there is a fair degree of over specification for lighting circuits anyway, since even the 1.0mm^2 cable is typically rated at least that of the MCB on most lighting circuits).
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replying to John Rumm, Yam man wrote: Thanks for the help advise will update how I get on. I'm glad there's still some helpful people out there. Cheers again. I'm adding the fused switch to the socket spur then in future I just need to add to that is this correct? Is there limit to the amount of sockets took from fused spur? Thanks again
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On 14/10/2017 15:44, Yam man wrote:

You can take any number of sockets from a fused spur, since the fuse will protect the spur cable from overload. There is a practical limit on how many sockets you add this way though since you can only support a maximum of around 3kW total load spread over all the sockets on your spur. Obviously as a designer you will need to decide what is appropriate based on the expected use.
With an unfused spur, when you are normally taking the spur in single run of 2.5mm^2 cable, sing you need some additional overload protection since the 32A MCB at the origin of the circuit won't do it. So in this situation you can acquire the required protection simply by limiting the maximum load that can be placed on the spur - allowing only one single or one double socket.
You could also extend the ring - which you can do at a single connection point if you want. Then you can have as many sockets as you want so long as the total floor area served does not exceed 100m^2:
http://wiki.diyfaq.org.uk/index.php/Easy_socket_extensions
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replying to John Rumm, Yam man wrote: Hi have jumped ahead with socket install John as I had access to plenty 2.5 MM cable. I have ran the spur off the socket and ran it around 15 ft under floor space then up inside cupboard clipped to the inside of door frame and ended in a 13 amp switched fused unit I am going to run the 2.5 directly up from the switch through the ceiling into my loft mounted on timbers is 1st double socket (run of around 14-18ft) which is all metal surface mounted then if I'm correct I run another length from that to my final socket. Not to sure about earthing though any input greatly appreciated. I use incoming earth from fused switch to face plate then fly earth from plate to back boxes is this all sound correct?
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On 14/10/2017 17:44, Yam man wrote:

Yup, you want earth continuity all the way through. Each socket daisy chained to the next (you can also branch any place it works out more convenient).
Its generally considered good practice to add a fly lead between one of the earth terminals on the socket to the earth lug on the back box if it has one. Remember to use yellow / green sleeving[1] on all the exposed earth wires - saves any problems with shorts etc as you fold them back into the boxes.
[1] the 2mm diameter stuff you get from the electrical wholesalers is easier and neater to use than the more common 3mm stuff you get in most of the DIY shops. Its also usually better practice to sleeve each earth independently rather than placing several in one sleeve, since it makes it easier to separate things later if you need to do so for testing purposes.
If you wire up all the new sockets before you connect them to your spur, you can do an easy test by shorting the L, N & E together at the unconnected cable at the start, then use a multimeter to measure the resistance between L&N, L&E, and N&E at the last socket. That will tell you if you have good connections all the way along. For added peace of mind you can compare the readings you get against the wire resistances shown here:
http://wiki.diyfaq.org.uk/index.php/Electrical_Circuit_Faults#Wire_resistance_table
(note CPC = Circuit Protective Conductor = Earth wire)
They ought to be close to the expected values for the length of cable you have.
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replying to John Rumm, Yam man wrote: Thanks for that John great stuff I've sorted the light curcuit connection and is spot on. Have spurred the socket off and under floor inside cupboard and put the 13amp fused switch (turned off and void of fuse) now tomorrow will run the sockets then test as advised. Will need to lend multimeter as ones I have are from old days and BIG chunky Bakelite things. Thanks again
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On Saturday, 14 October 2017 22:44:04 UTC+1, Yam man wrote:

and

nd

l run

have

A bakelite multimeter should be fine. As is a £2 new one for testing U Npowered mains circuits.
NT
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On 14/10/2017 22:44, Yam man wrote:

As long as it has a decent low ohms range will do the job...
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