Using heat shrink for wire insulation - UK Vintage Radio Repair and Restoration Discussion Forum

magician · 24th May 2023, 8:05 am

Hi,
I'm wanting to use heat shrink to insulate all wiring in a project. Would there be any negatives to doing this?
It is a lot cheaper for me to purchase bare solid core wiring and use heat shrink to insulate the wire in different colours than to purchase different colours of already insulated wire.
I have made some already using 2 layers of heat shrink and it seems fine. When bending the wires, I don't see any stress in the heat shrink either.
I have searched the forums and internet and can find very limited information to other people doing this but I wanted advice if it is an appropriate practice.

Appologies if I have posted this in the wrong section.

Thanks.

stevehertz · 24th May 2023, 8:21 am

Personally, unless someone can come up with 'scientific' reasons why this shouldn't be done, I can't see anything wrong with it. Saying that, insulating sleeving is readily available and is an option.

trobbins · 24th May 2023, 8:40 am

Thickness of solid insulation is one aspect of the voltage rating of a wire (along with a whole bunch of other aspects).

Perhaps you could stay with appropriately rated wire for mains ac circuitry.

Perhaps you could assess what the collateral damage could be if adjacent wires somehow touched through damaged insulation, then make your own risk call.

Perhaps you could add some coloured heatshrink to the ends of wires that you wanted to colour code - that is common practise for larger industrial wiring which only comes in one colour.

Gabe001 · 24th May 2023, 8:59 am

I buy solid core multiple coloured PVC sleeved Tinned Copper Wire from AliExpress and it's very cheap. I've never managed to find solid core silicon sleeved wire yet, which would be awesome. As you know PVC sleeving doesn't like heat from the soldering iron, but it's OK for most things. Voltage rating 300V.

I did manage to find silicone sleeving for bare wire though, and it comes in really useful sometimes when re-sleeving radio wires with crumbling insulation - unsolder one end, resleeve and resolder. It's neater than heat shrink, thicker and unaffected by the heat from the soldering iron. The yellow is a bit too translucent but the rest of the colours are fine.

Kr
Gabriel

magician · 25th May 2023, 1:21 pm

Thanks, to everyone who replied and gave thoughts/suggestions. After doing some more research, I did find some 22 AWG 600V solid core on mouser in different colours that was surprisingly affordable. It's the adafruit brand. With the 18 AWG, I can get solid core lighting cable in white/red/black which should suffice.
Also @trobbins, I should have been more specific that the wiring in question is post mains wiring but very good point!

duncanlowe · 25th May 2023, 6:56 pm

I will add, that I have seen that heatshrink isn't physically robust if any mechanical force is applied. In my particular issue it could be partly due to the sleeving applied over the top of the heatshrink, too. Overall a design disaster.

Basically there was an installation where a feed was too close to a return path. The installation relied on the heatshrink and an outer layer of I think glassfibre reinforced sleeving in case the process for achieving acceptable separation wasn't stuck to by the assemblers. Of course, this was relied on instead of making sure the assembly process and design just worked.

Nah. All of that sleeving wore through pretty fast in service and led to some interesting overcurrent events before proper design spacing was done. I did keep the worn / melted piece in my black museum for a while! BTW when I say in service, it was only ever in service during development and testing, but did cuse me to have a quite interesting Sunday evening conversation about suspending testing of all prototypes until the issue was fixed.

So, back to the point: heatshrink is great for some things but is far from a panacea.

24th May 2023, 8:05 am	#1
magician Triode Join Date: Dec 2019 Location: Darwin, Northern Territory, Australia Posts: 12	Using heat shrink for wire insulation Hi, I'm wanting to use heat shrink to insulate all wiring in a project. Would there be any negatives to doing this? It is a lot cheaper for me to purchase bare solid core wiring and use heat shrink to insulate the wire in different colours than to purchase different colours of already insulated wire. I have made some already using 2 layers of heat shrink and it seems fine. When bending the wires, I don't see any stress in the heat shrink either. I have searched the forums and internet and can find very limited information to other people doing this but I wanted advice if it is an appropriate practice. Appologies if I have posted this in the wrong section. Thanks.

24th May 2023, 8:21 am	#2
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,833	Re: Using heat shrink for wire insulation Personally, unless someone can come up with 'scientific' reasons why this shouldn't be done, I can't see anything wrong with it. Saying that, insulating sleeving is readily available and is an option. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

24th May 2023, 8:40 am	#3
trobbins Heptode Join Date: Oct 2009 Location: Melbourne Australia Posts: 901	Re: Using heat shrink for wire insulation Thickness of solid insulation is one aspect of the voltage rating of a wire (along with a whole bunch of other aspects). Perhaps you could stay with appropriately rated wire for mains ac circuitry. Perhaps you could assess what the collateral damage could be if adjacent wires somehow touched through damaged insulation, then make your own risk call. Perhaps you could add some coloured heatshrink to the ends of wires that you wanted to colour code - that is common practise for larger industrial wiring which only comes in one colour.

24th May 2023, 8:59 am	#4
Gabe001 Octode Join Date: Oct 2019 Location: Stockport, Greater Manchester, UK. Posts: 1,646	Re: Using heat shrink for wire insulation I buy solid core multiple coloured PVC sleeved Tinned Copper Wire from AliExpress and it's very cheap. I've never managed to find solid core silicon sleeved wire yet, which would be awesome. As you know PVC sleeving doesn't like heat from the soldering iron, but it's OK for most things. Voltage rating 300V. I did manage to find silicone sleeving for bare wire though, and it comes in really useful sometimes when re-sleeving radio wires with crumbling insulation - unsolder one end, resleeve and resolder. It's neater than heat shrink, thicker and unaffected by the heat from the soldering iron. The yellow is a bit too translucent but the rest of the colours are fine. Kr Gabriel Attached Thumbnails

25th May 2023, 1:21 pm	#5
magician Triode Join Date: Dec 2019 Location: Darwin, Northern Territory, Australia Posts: 12	Re: Using heat shrink for wire insulation Thanks, to everyone who replied and gave thoughts/suggestions. After doing some more research, I did find some 22 AWG 600V solid core on mouser in different colours that was surprisingly affordable. It's the adafruit brand. With the 18 AWG, I can get solid core lighting cable in white/red/black which should suffice. Also @trobbins, I should have been more specific that the wiring in question is post mains wiring but very good point!

25th May 2023, 6:56 pm	#6
duncanlowe Nonode Join Date: Jan 2016 Location: Stafford, Staffs. UK. Posts: 2,532	Re: Using heat shrink for wire insulation I will add, that I have seen that heatshrink isn't physically robust if any mechanical force is applied. In my particular issue it could be partly due to the sleeving applied over the top of the heatshrink, too. Overall a design disaster. Basically there was an installation where a feed was too close to a return path. The installation relied on the heatshrink and an outer layer of I think glassfibre reinforced sleeving in case the process for achieving acceptable separation wasn't stuck to by the assemblers. Of course, this was relied on instead of making sure the assembly process and design just worked. Nah. All of that sleeving wore through pretty fast in service and led to some interesting overcurrent events before proper design spacing was done. I did keep the worn / melted piece in my black museum for a while! BTW when I say in service, it was only ever in service during development and testing, but did cuse me to have a quite interesting Sunday evening conversation about suspending testing of all prototypes until the issue was fixed. So, back to the point: heatshrink is great for some things but is far from a panacea.