≥6-core flex?

[pete01]

Wireless switching might be easier

 

[JohnW2]

Wireless switching might be easier

Yep, that's always been there as a 'Plan Z', as has digging out a chase for a couple of cables.

However, if, as I suspect/hope, pulling a single small round cable through that short length of conduit proves to be fairly 'easy' that presumably would/will be the simplest/quickest solution of all?

 

[333rocky333]

Is there a reason for not wanting black cores

 

[pete01]

Yep, that's always been there as a 'Plan Z', as has digging out a chase for a couple of cables.

However, if, as I suspect/hope, pulling a single small round cable through that short length of conduit proves to be fairly 'easy' that presumably would/will be the simplest/quickest solution of all?

I dont think you'll do it it looks similar to my house and those conduits are about 16mm, ok for a twin and earth but not much more.

 

[JohnW2]

Is there a reason for not wanting black cores

No, not really - which is why I remain attracted to the TLC YY cable.

 

[JohnW2]

I dont think you'll do it it looks similar to my house and those conduits are about 16mm, ok for a twin and earth but not much more.

Are you talking about the (black-cored) TLC YY? If so, the 0.5 mm² and 0.75² versions are seemingly tiny and more than adequate (even if perhaps arguably 'non-compliant'), but even 1.0 mm² is only 8.3 mm OD. Are you really suggesting that might be a problem? ....

 

[pete01]

If you had it on a bench possibly no problem, installed reaching under floor etc not so easy but....

All you can do is try....plenty of yellow 77 might help

 

[JohnW2]

If you had it on a bench possibly no problem, installed reaching under floor etc not so easy but....

Both ends of the short and straight length of conduit are fully exposed.

All you can do is try....plenty of yellow 77 might help

I remain a little surprised by your doubts - even the 1.0 mm² YY is about the same as 1.5 mm² T+E in one dimension (and a fair bit less than the T+E in the ther dimension) and the 0.5 mm² and 0.75² mm YYs smaller than even that.

I'm certainly tempted to use 0.75² mm. Even though BS7671 'requires' a minimum of 1 mm² for a lighting (or,now, also a 'power') circuit, it has an adequate CCC for a 6A circuit. Would you be happy be that (if Mr Jobsworth was not looking over your shoulder)?

 

[pete01]

Both ends of the short and straight length of conduit are fully exposed.

I remain a little surprised by your doubts - even the 1.0 mm² YY is about the same as 1.5 mm² T+E in one dimension (and a fair bit less than the T+E in the ther dimension) and the 0.5 mm² and 0.75² mm YYs smaller than even that.

I'm certainly tempted to use 0.75² mm. Even though BS7671 'requires' a minimum of 1 mm² for a lighting (or,now, also a 'power') circuit, it has an adequate CCC for a 6A circuit. Would you be happy be that (if Mr Jobsworth was not looking over your shoulder)?

I would definitely use 0.75mm, anything for an easy life

 

[Sureitsoff?]

bit longer than you need but handy for future use...............

https://www.ebay.co.uk/itm/266263956669?_skw=7+core+cable&itmmeta=01KXBBPDMG5T1XF2EP0092DZ6R&hash=item3dfe918cbd%3Ag%3AONIAAOSwxfBkZ62U&itmprp=enc%3AAQALAAAA0GfYFPkwiKCW4ZNSs2u11xCm--Gk1SDVmxd0rk2loDqiE5tNZbok86eHV%2BP9vfFss5937h2okgJJvKfOVqnZGN1deIbgAnv8%2BkCdpjOeEqNV30tmwlPxcspYi0fcYM%2BHypveXzsFQq9DQ3DuRzmWoKAcZLxQk4tA37krZFK49D5QBsYosiZoMmJhQs62eFwIp3uogL6ELqn1gMByD7EVRGVr7Yn8jIbiSObBMhMMH2%2BvOZuIvVCistcmQz%2B8wMJQpCJveSz7vZLnhAeytuqoXmo%3D%7Ctkp%3ABk9SR9Da2evqZw&LH_ItemCondition=3000

 

[JohnW2]

I would definitely use 0.75mm, anything for an easy life

Quite so. This seems to be roughly the situation (comparison of YY to 3C+E), roughly to scale. ....

 

[mikehammer69]

On balance I would be looking at a wireless solution rather than using smaller than allowed cabling

Buy hey that's just me

 

[JohnW2]

bit longer than you need but handy for future use............... (link- click here)

Thanks. Yes, that would do the job but, as you point out, nearly 20 times more than I need- £60 (including the £10 postage) seems more than a bit OTT for replacing about 5 feet of small cable

 

[JohnW2]

On balance I would be looking at a wireless solution rather than using smaller than allowed cabling

No need for that - 1.0 mm² YY (which is 'allowed') is only fractionally larger but, electrically speaking, totally unnecessary for supplies to two LED lights

In fact, as with so many things about BS7671, it's requirements are not totally clear. Per the final row of Table 52.3, a 0.75 mm² flexible cable "for any other application" (whatever that may mean!) IS 'allowed'! I would/will be more than happy with 0.75 mm².

 

[SUNRAY]

Quite so. This seems to be roughly the situation (comparison of YY to 3C+E), roughly to scale. ....

View attachment 418262

If your scaling is anywhere near correct (it looks to be in the pic) I wonder why you are not looking at staying with 3C&E

As long as kept flat and straight should not be too much of an issue over a couple of metres which I imagine is more than enough for your purpose.

I haven't made a scaled comparison with 20 mm but I've frequently run 2*2.5mm² T&E in 20mm tube which many seem to struggle with


My thoughts about singles are purely based around ease of pulling in, (I've certainly run significantly more than 7 into 5/8" tube) however it does mean making some arrangement at both ends to contain the wires into some form of enclosure. - In the case I mentioned earlier I changed the plastic buried backbox for a metal version regardless and was able to screw a 1G backbox to a joist with a wooden spacer with the tube entering a 20mm knockout using a rubber grommet above the ceiling.