Type Of Mains Cable For Alarm

stator

unforeseen wrote: »

It sounds more like the electrician who only has 2.5 tc with him just used a spare bit as an indicator that the box could be connected to.

Otherwise you are sitting wondering what the fused spur is feeding as it may have all been chased into the wall.

Electricians who are employed to wire houses tend not to carry low power stuff as it isn't required for what they do

He would have had 1 sqmm or 1.5 sqmm Twin Core & Earth for lighting.

Risteard

stator wrote: »

He would have had 1 sqmm or 1.5 sqmm Twin Core & Earth for lighting.

1mm^2 non-flexible cable is not permitted for anything other than lighting circuits though, which an intruder alarm circuit is not.

Grenage

Risteard wrote: »

1mm^2 non-flexible cable is not permitted for anything other than lighting circuits though, which an intruder alarm circuit is not.

What? Really?

Surely it's permitted for any circuit where the load is within tolerance? Something under 10A.

Risteard

Grenage wrote: »

What? Really?

Really, and this has been the case since Amendment No. 1 to BS 7671:2008 in 2011.

Grenage

Cheers; as you can tell, I'm not a sparky. Just seemed a bit odd to me that the regs would say that a cable is only suitable for one specific purpose, regardless of load or how it was fused.

unforeseen

stator wrote: »

He would have had 1 sqmm or 1.5 sqmm Twin Core & Earth for lighting.

But if he was putting in a spur using 2.5 then he would have that to hand and probably an offcut lying at his feet after cutting it back to the right length during fitting.

Risteard

Grenage wrote: »

Just seemed a bit odd to me that the regs would say that a cable is only suitable for one specific purpose, regardless of load or how it was fused.

If I was a betting man I would suggest that the likely reason is to harmonise with the rest of Europe who do not use cable smaller than 1.5mm^2. However the exemption for lighting circuits on 1mm^2 was used as a halfway house as many would have protested banning it altogether given that that was the way they had always done it. I suspect 1mm^2 (non-flexible) will go altogether when the 18th Edition is published in 2018.

Here it is practically impossible to purchase 1mm^2 and no-one uses it. And 1.5 miles down the road across the border it is actually prohibited.

Grenage

Cheers! That does make sense; I've never used anything smaller than 1.5 for lighting circuit repairs, probably because at the time the price difference was negligible, or 1mm wasn't available.

wroenaldinho

going to use this cable from the spur to the alarm panel.

http://www.maplin.co.uk/p/round-3-core-15mm-pvc-flex-15a-3183y-hank-white-5m-a29tl

Thanks