External cable or conduit?

[Bob]

Hi

I am installing an outside floodlight, to be fixed on the wall of my house. I plan to run about 5m of twin core and earth cable from the garage, connecting via a fused connection unit, and clip the cable to the nearest wall. Is it ok (Wiring Regs) to do this, or do I need to enclose it within a plastic conduit? I seem to remember reading that plastic conduit was not suitable in low temperatures. Cable run is mostly horizontal, but with quite a lot of bends, so would be easier without conduit.

TIA

Joe

[Dave Plowman (News)]

Why not use cable suitable for the job in one go? Hi-Tuf

is one type. It also has weatherproof glands for the cable entry to the light. It's no more difficult to use than TW&E.

Wicks used to sell it in pre-cut lengths. I can't say I looked elsewhere.

[Osprey]

T&E is not good outside - it gets affected by UV in sunlight, insulation goes brittle. The suggestion of Hi-Tuff is OK ... bit of a sod to strip outer sheath in cold weather.

I used product from TLC ... the flexible conduit, with necessary gland, and used standard PVC flex within it.

my case I coupled it to 20mm conduit at the wall as it passed through the cavity wall, and regs don't like cables in the cavity. The conduit can't be seen, and it just looks like flexible conduit gland is screwed into wall - neat solution.

[Dave Plowman (News)]

Easy with a rotary cable stripper. They're well worth having for ordinary round flex too - and not expensive. Look for the type that takes ordinary Stanley knife blades.

[John]

I don't know where people get this idea from. We've had a length of 1.0mm T&E on our back (south facing) wall feeing the outside light for about 19 years and it's still OK.

[David Hansen]

On Wed, 22 Nov 2006 09:37:34 -0000 someone who may be "Bob" wrote this:-

There is no simplistic answer to this.

Twin and earth is susceptible to direct sunlight and cold, both of which do nasty things to the sheath and insulation. Unless your cable is out of the sunlight and in a place where it does not get cold, you didn't describe the installation conditions, then it is a good idea to enclose it in conduit. Plastic is fine in most conditions.

Unless you are in a warm place I would suggest that this is not the time of year to install either.

[David Hansen]

On Wed, 22 Nov 2006 14:41:16 -0000 someone who may be "John" wrote this:-

How do you define "OK"?

[John]

Well, I recently had to unclip part of the cable run to do some other work and it didn't disintegrate in my hands, didn't break, and seemed to be still quite flexible. Having said that, I wasn't being rough with it and I was putting it back in the same place so I didn't have to go bending it anywhere - like I said, it seems OK.

John.

[gort]

If you use black plastic conduit leave some form of expansion joint in the run otherwise in hot weather it will have a tendency to buckle.

Dave

[Osprey]

Well you are luckly, I have seen badly affected T&E and flex ... UV leeches out the plasticiser - fact What you are left with is a brittle sheath ... which start cracking with extremes of weather - and then you get water penetration.

[Andrew Gabriel]

Whilst I've heard this a number of times, I have never come across any which has deteriorated outside. I disconnected a

15 year old length last year, and it's still as good as new, and I connected a new outside lamp to a piece which is greater than 20 years old (possibly much greater), also just as good as new.