LSF, is there a regulatory requirement?

[GBDamo]

I've been installing this stuff for years in commercial settings, it seems a no brainer.

For the first time, today, a client questioned its requirement and, to be honest I cant find anything in black and white to back up my assertion.

I know the advantages, and tried explaining these but he's adamant if its not legally required, he don't want it.

In this case the peace of mind would amount to ~£150 in a 1/2million pound project.

So, have I been talking gonads or is there something more concrete?

 

[Julie.]

I have done it that way but usually just part-cut the sheath to make it easier to use the CPC as a rip-cord. A knife is handy but also very easy to nick the primary insulation, sadly done that a bit too often and had to cut and strip again

The way I was taught was to "ring" the outer sheath where you needed to stop, then go between neutral and cpc, angling the blade towards the cpc, it slides smoothly along the bare copper, so easily the issue isn't nicking the neutral insulation, but going too far!

Once you get to the ringed part, stop at or before it, then pull the outer off the line and neutral and it snaps off giving a perfect end without the uneven sheath end that appears inevitable when tearing the cpc through the sheath.

It's very quick once you have the technique, every bit as quick as tearing the cpc, (assuming you do or do not ring the sheath in both methods)

 

[Vortigern]

The thing to remember on using a knife is that you are not cutting but scoring. So having scored around the sheath that is plenty enough does not take much pressure then snap the cable sideways and it splits at that point. Again you only need to score down the sheath to then pick the earth out and use it as a rip cord on the scored part and it comes out with very little pressure required.

 

[dennisbrown]

Just never crossed my mind to strip T&E with a knife. Makes sense I guess, especially with larger sizes, and knife control is essential for any shape of cable - possibly moreso with round as outer sheath continually varies in thickness when stripping in a straight line.

controlling a knife to cut the sheath ? Controlling is even a deal, my first month apprentice can do it quiet easily

 

[Electro-tech]

I have used LSF cable when specified but after reading below I think it may well have to be LSHF depending on the manufacturer.

What is LSF cable?​

If burning PVC cables present such a potential hazard to life then surely cable labelled and marketed as Low Smoke & Fume, or LSF as it’s commonly referred to, provides the answer. Unfortunately that’s not the case, as LSF is also manufactured using PVC compounds. The PVC in question is modified to varying degrees dependant on the manufacturer’s choice of additives, but generally it still produces fairly high volumes of dense black smoke and HCl emissions. In truth there is little by way of standards to dictate what the emission differentials between LSF and PVC cables should be, which explains the wide variation of results when tested; some LSF products producing 15% HCl while others are responsible for up to 24%. In short, LSF flexible cable’s a bit like Forrest Gump’s box of chocolates – ‘You never know what you’re gonna get’.

 

[nicebutdim]

controlling a knife to cut the sheath ? Controlling is even a deal, my first month apprentice can do it quiet easily

Welcome to the forum. Perhaps if you'd read all posts, rather than take one in isolation, conversations will make more sense.

T&E that we use in the UK is a flat cable, similar to Romex. As such there are many means of stripping it that are much quicker than using a knife. Knives certainly have their place and I use one daily for stripping various types of cables - just not flat stuff.

 

[Dustydazzler]

Welcome to the forum. Perhaps if you'd read all posts, rather than take one in isolation, conversations will make more sense.

T&E that we use in the UK is a flat cable, similar to Romex. As such there are many means of stripping it that are much quicker than using a knife. Knives certainly have their place and I use one daily for stripping various types of cables - just not flat stuff.

I have seen quite a few Americans / Canadians on Youtube split a twin and earth ( Romex ) by gidding a sharp knife straight down the centre line. I don't like this method if you go slightly off centre you will cut into the insulation of the cores

I really don't like this method

 

[nicebutdim]

I have seen quite a few Americans / Canadians on Youtube split a twin and earth ( Romex ) by gidding a sharp knife straight down the centre line. I don't like this method if you go slightly off centre you will cut into the insulation of the cores

I really don't like this method

I used a knife to strip a few T&Es after the conversation with @ipf

While I'd routinely split sheaths of NYY etc with a knife, it didn't strike me as the best method of stripping T&E. A number of colleagues nibble the sheath of flex with side cutters, whereas I'd use croppers to ring most round cables, then pull the sheath away on short lengths or run a knife down longer lengths. I guess it's a case of horses for courses - and even first month apprentices.

 

[ipf]

I have seen quite a few Americans / Canadians on Youtube split a twin and earth ( Romex ) by gidding a sharp knife straight down the centre line. I don't like this method if you go slightly off centre you will cut into the insulation of the cores

I really don't like this method

I agree, total rubbish way....and dangerous.

 

[ipf]

I used a knife to strip a few T&Es after the conversation with @ipf

While I'd routinely split sheaths of NYY etc with a knife, it didn't strike me as the best method of stripping T&E. A number of colleagues nibble the sheath of flex with side cutters, whereas I'd use croppers to ring most round cables, then pull the sheath away on short lengths or run a knife down longer lengths. I guess it's a case of horses for courses - and even first month apprentices.

I do hope that you weren't presuming that was my method of knife stripping T+E.........it's horrid.

 

[nicebutdim]

I do hope that you weren't presuming that was my method of knife stripping T+E.........it's horrid.

Hadn't watched the video and, no, that's not at all what I had in mind. It's brutal - I've never seen anything like it!

 

[Dustydazzler]

Hadn't watched the video and, no, that's not at all what I had in mind. It's brutal - I've never seen anything like it!

Another butcher at work Look away now if you are squeamish

 

[nicebutdim]

Another butcher at work Look away now if you are squeamish

These people are mad - might as well use a grinder.

 

[littlespark]

I use a knife between cpc and A.N Other core to start off… far too easy to misalign and remove some of the inner insulation if going all the way.

Give myself a few inches to hold onto, and pull the L and N apart.



Did it once as a naive apprentice in a live 3ph board. Cpc coiled up and slipped between the gap beside the MCB’s that were fitted…..

No more cpc of any considerable length!