Electrical Insulation Tape

[SimonH2]

But would we have anything which conformed to the appropriate standards for a cable?
...
No, but I would argue that such an assembly would not conform to any standards recognised by BS 7671 for cables.

But, with the qualifier of not having done an exhaustive search, BS7671 does not in many cases specify a standard to be applied. In some cases it does (eg 717.52.1), but in many it does not (eg 715.521.1 where it refers to "Insulated conductors", "Rigid cables", and "Flexible cables"). Only "flexible cable" appears in section 2 where it is merely defined as a cable suitable for being flexed.

So in answer to your challenge ...
If installing an ELV lighting system (section 715) with bare conductors, it would appear that instead of joining a section of insulated cable, it would be allowed to simply continue the bare wires past the last of the support insulators and insulate them with tape to the terminals of the transformer. Indeed it could be argued that this would be preferable to introducing additional high current connections where the transformer is very close to the lighting setup. Would I do it with tape ? Generally no, I'd use sleeving (likely heat-shrink) which would be easier and neater but have (almost) exactly the same questions as using tape.

 

[sparkwright]

Just lately all 'insulation' tape seems to break very easily when rolling it off.

So what is the correct use for it?

Taping cables to draw tapes and fishing rods.

Taping up connector blocks on live cables as a temporary measure when plastering, decorating etc gets done.

Already the second usage looks controversial already.

 

[Harry Bloomfield]

As a next step, we might take several of such insulated bars, put them together, and wind a layer of insulating material - again for convenience we'll use long thin strips sold as tape - and we have what might otherwise be called a cable. Or we might, for a variety of reasons, use a different technique for providing that second layer - it might be an extruded covering, and it might even be of a conductive material.

Indeed, that is how larger cables used to be made, the paper insulated ones, lead covered. Waxed paper tape was wrapped round and round the cores, to build up the depth of insulation, then an outer of lead over the top. Making the ends off, involved plumbing or sweating the lead, then the paper insulation needed to be 'potted' with a hot tar like compound. All good fun..

 

[Harry Bloomfield]

Just lately all 'insulation' tape seems to break very easily when rolling it off.

So what is the correct use for it?

I suspect your breaking tape is one of the cheaper makes, or it is being used at well below zero. I took a roll of red tape out of my garage workshop today, it must have been on the shelf at least 10 years and it is fine. Even the PVC on armoured cable can shatter, in really cold weather.

In the early days, insulation tape use was encouraged, but back then 'screwit' cable joints were acceptable, as were cable joints in conduit boxes. Tape was also used as a means to bunch cables prior to pulling them into conduits, to prevent tangles. These days I would only use tape as temporary cable markers.

 

[sparkwright]

I considered the tape to be a good make, for me breaking tape has been issue before the winter weather.

 

[SimonH2]

Ordinary PVC does get brittle at low temperatures (as do some other plastics). I've seen a lot of cable reels with a warning not to install below freezing - so you see sparkies getting the reels out of the van where they've been freezing nicely overnight and start pulling them in, either ignorant of the issues, or assuming that because the gas heater has taken the chill off the air then it's all OK.
I've found PVC tape (even "good" ones) to be fragile when very cold, keeping in trouser pocket for a while, or just holding it in my hand, solves that problem.

 

[ban-all-sheds]

I've seen a lot of cable reels with a warning not to install below freezing

John and I both have experienced the delight of wrestling with a particular brand of hituf at low temperatures.

 

[ban-all-sheds]

So in answer to your challenge ...
If installing an ELV lighting system (section 715) with bare conductors, it would appear that instead of joining a section of insulated cable, it would be allowed to simply continue the bare wires past the last of the support insulators and insulate them with tape to the terminals of the transformer. Indeed it could be argued that this would be preferable to introducing additional high current connections where the transformer is very close to the lighting setup. Would I do it with tape ? Generally no, I'd use sleeving (likely heat-shrink) which would be easier and neater but have (almost) exactly the same questions as using tape.

Thanks for that - I'll have a look.

The point of my challenge has never been "I'm right, you'll fail to prove me wrong". Of course I think I'm right, but if I'm wrong because of ignorance I naturally welcome the education.

 

[JohnW2]

John and I both have experienced the delight of wrestling with a particular brand of hituf at low temperatures.

At least in my case, even at fairly high (for UK) temperatures. That stuff was awful, and, as folk here know, I've kept a bit just to remind me of that!