Insulation properties of heat shrink, and tape

haptism · Sep 5, 2018

Have question thats been on my mind for a while. Does anyone know if; at 250 -500 v, a single layer of heat shrink, or a single layer of insulation tape for that matter, covering a bare conductor, sufficient insulation against ?? direct contact/a shock ?

It seems a bit thin in comparison to to the outer sheathing of singles/flex. I could conduct a test with IR test but thought to ask the forum. Obviously a single layer of insulating tape is not the norm but this is in the name of science so go easy.

Pete999 · Sep 5, 2018

haptism said:
Have question thats been on my mind for a while. Does anyone know if; at 250 -500 v, a single layer of heat shrink, or a single layer of insulation tape for that matter, covering a bare conductor, sufficient insulation against ?? direct contact/a shock ?

It seems a bit thin in comparison to to the outer sheathing of singles/flex. I could conduct a test with IR test but thought to ask the forum. Obviously a single layer of insulating tape is not the norm but this is in the name of science so go easy.

You could have a point Mate, never gave it much thought before, perhaps I should have, good point though, would have thought the suppliers of the heat shrink would have taken that issue into account, but you never know, await answers with a degree of anticipation.

davesparks · Sep 5, 2018

Like so many things it will come down to checking with the manufacturer. A good quality heatshrink which has been designed and tested as electrical insulation will be good for the job, whereas basic thin heatshrink may only be good for marking or bundling cables together.

If you look on YouTube you’ll find various instruction videos of how to install various cable joints using heatshrink and/or tape. These will give you an idea of the types of insulation materials used and how much is applied for different voltages.

Tape is often used just to cover rough edges or build up layers to give the heatshrink a smooth surface to be applied to.

FatAlan · Sep 5, 2018

Need to get JW on the case, rig up and video some IR tests and see if there is any leakage

MDJ · Sep 5, 2018

haptism said:
Have question thats been on my mind for a while. Does anyone know if; at 250 -500 v, a single layer of heat shrink, or a single layer of insulation tape for that matter, covering a bare conductor, sufficient insulation against ?? direct contact/a shock ?

It seems a bit thin in comparison to to the outer sheathing of singles/flex. I could conduct a test with IR test but thought to ask the forum. Obviously a single layer of insulating tape is not the norm but this is in the name of science so go easy.

I always used two layers of heat shrink, I thought this was the standard way of doing it, but I suppose we all do different things

haptism · Sep 5, 2018

davesparks said:
Like so many things it will come down to checking with the manufacturer. A good quality heatshrink which has been designed and tested as electrical insulation will be good for the job, whereas basic thin heatshrink may only be good for marking or bundling cables together.

If you look on YouTube you’ll find various instruction videos of how to install various cable joints using heatshrink and/or tape. These will give you an idea of the types of insulation materials used and how much is applied for different voltages.

Tape is often used just to cover rough edges or build up layers to give the heatshrink a smooth surface to be applied to.

Yeah I suppose its down to sourcing quality and reading specs ect, although insulation tape is called insulation tape.

Andy78 · Sep 5, 2018

According to B&Q light fitting instructions you should use three layers of tape round the connector block they supply for the looped line.
So that's that settled then.

Toneyz · Sep 5, 2018

Andy78 said:
According to B&Q light fitting instructions you should use three layers of tape round the connector block they supply for the looped line.
So that's that settled then.

What does Ikea recommend?

Andy78 · Sep 5, 2018

anthonybragg said:
What does Ikea recommend?

No idea, it's all in pictures

Simon79 · Sep 5, 2018

haptism said:
Have question thats been on my mind for a while. Does anyone know if; at 250 -500 v, a single layer of heat shrink, or a single layer of insulation tape for that matter, covering a bare conductor, sufficient insulation against ?? direct contact/a shock ?

It seems a bit thin in comparison to to the outer sheathing of singles/flex. I could conduct a test with IR test but thought to ask the forum. Obviously a single layer of insulating tape is not the norm but this is in the name of science so go easy.

This is 2 bits of 2.5mm one single wrapped with insulation tape then taped together tested at 250 / 500 and 1000v >999mohms

same with heat shrink

[ElectriciansForums.net] Insulation properties of heat shrink, and tape

Wilko · Sep 5, 2018

Hi - it's an interesting question. Extending from @davesparks thoughts in post #3, we need good quality materials, as there may be a difference between what works when you test it and what's good for "10 year performance in a pollution degree 3 environment".

davesparks · Sep 5, 2018

The results of a standard insulation resistance test aren’t really good enough to judge this by.
If the thickness of a single layer of tape was acceptable insulation then cable manufacturers wouldn’t make insulation as thick as it is.

You could wrap a conductor in a single layer of cling film and probably pass an IR test, but that sure as hell isnt acceptable as an insulating layer.

haptism · Sep 5, 2018

Simon79 said:
This is 2 bits of 2.5mm one single wrapped with insulation tape then taped together tested at 250 / 500 and 1000v >999mohms

same with heat shrink

View attachment 44138

Thats a surprising result considering and a great reply with the photo's. Good call

Deleted member 26818 · Sep 6, 2018

Those croc clips are the wrong colours.

DPG · Sep 6, 2018

Always worries me when I'm in the pound shop and I see 8 roles of insulating tape for a quid. Obviously will never have been near any testing to prove its effectiveness.