Author Topic: Is heatshrink tube a good insulator?  (Read 1035 times)

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Offline exe

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Is heatshrink tube a good insulator?
« on: February 20, 2019, 09:01:25 pm »
Hi!

I wonder if I can use heatshrink tube to insulate spade blade terminals? It's for mains voltage (230V).
 

Offline luma

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Re: Is heatshrink tube a good insulator?
« Reply #1 on: February 20, 2019, 09:07:59 pm »
That depends on the tubing.  The datasheet for the specific tubing should list the "dielectric strength" which is the spec you're looking for.
 

Offline exe

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Re: Is heatshrink tube a good insulator?
« Reply #2 on: February 20, 2019, 09:14:07 pm »
huh, that complicates things as my tubes are from aliexpress... Okay, I'm afraid the answer is no in this case.....
 

Online blueskull

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Re: Is heatshrink tube a good insulator?
« Reply #3 on: February 20, 2019, 09:16:27 pm »
Polyolefin is a great insulator, but you still want to use only UL/CSA/whatever certified ones just in case.
They usually breakdown at at least 900V/mil, so a typical 20mil wall thickness yields 18kV breakdown voltage.
However, due to reliability, manufacturing defects and transient concerns, they are usually rated up to 600Vrms (4kVpk for CAT II).
Your 230Vrms application will not be a problem, as long as your tubes are safety rated accordingly.
 

Offline Zenith

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Re: Is heatshrink tube a good insulator?
« Reply #4 on: February 20, 2019, 11:37:37 pm »
There are spade connectors sold with PVC sleeves and I believe you can get the sleeves separately.  I've seen them used on switches etc at mains voltage. I'd rather use them than heatshrink.

What's the requirement? I'm sure that in things like washing machines they don't use anything more than the PVC sleeves.

I've never regarded heatshrink at mains voltage as very much more than a courtesy. The connection could be bare, as it's enclosed and unlikely to come into contact with anything or anyone, unless they ignore the warning label and take definite steps, but it's safer and neater to put heatshrink on, and you can usually put on a couple of layers of heatshrink if you want. 230V shocks are unpleasant, but not often lethal.

« Last Edit: February 20, 2019, 11:39:34 pm by Zenith »
 

Offline Fungus

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Re: Is heatshrink tube a good insulator?
« Reply #5 on: February 21, 2019, 08:55:36 am »
...you can usually put on a couple of layers of heatshrink if you want.

This.
 

Online Berni

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Re: Is heatshrink tube a good insulator?
« Reply #6 on: February 21, 2019, 09:05:00 am »
If its for a DIY project sure go ahead as long as its decently thick heatshrink to make sure it wont tear open on any sharp corners.

If its for an actual product that is sold then buy the proper stuff from the manufacturer of the terminals or get name brand heatshrink with UL listings and all that.
 

Offline Fungus

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Re: Is heatshrink tube a good insulator?
« Reply #7 on: February 21, 2019, 10:09:28 am »
It's gotta be better than electrician's tape.  :popcorn:

(nb. make sure there's no sharp bits of metal sticking out before you shrink it)
 

Offline exe

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Re: Is heatshrink tube a good insulator?
« Reply #8 on: February 21, 2019, 10:19:11 am »
What's the requirement?
[...]
I've never regarded heatshrink at mains voltage as very much more than a courtesy. The connection could be bare, as it's enclosed and unlikely to come into contact with anything or anyone, unless they ignore the warning label and take definite steps, but it's safer and neater to put heatshrink on, and you can usually put on a couple of layers of heatshrink if you want. 230V shocks are unpleasant, but not often lethal.

Uhm, I'm building a power supply and trying to "do things right". I use quick-fit connectors on the primary side. I do have isolated connectors, but I don't have the right crimper yet (just ordered one from aliexpress as branded ones cost way too much for ten connector I need to crimp). Since it's gonna take a while till it's delivered I decided to solder an uninsulated crimper and put a heatshrink on it.

I know soldering connectors is a bad idea, but do you think it's fine for a simple setup like a bench power supply? Assuming I use proper flux.
 

Offline Fungus

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Re: Is heatshrink tube a good insulator?
« Reply #9 on: February 21, 2019, 10:24:20 am »
I know soldering connectors is a bad idea, but do you think it's fine for a simple setup like a bench power supply? Assuming I use proper flux.

If no fingers or screwdrivers are going to be near it when it's powered on then heatshrink is fine.

If it's not going to be vibrating or moving around then soldering the connectotors is probably OK, too.
 

Offline Electro Detective

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Re: Is heatshrink tube a good insulator?
« Reply #10 on: February 21, 2019, 11:12:14 am »
Two layers of cheep heatshrink should cope ok with 230 volts.

or wrap a few turns of GOOD electrical tape (NITTO?)  around the spade connector and then a layer of cheep heatshrink on top


My current quick fix 'good enough' fav is that overpriced SOS silicone  ---stretch---   'repair' tape which seals itself to itself nicely.

If I want the job to not get done again for a LONG TIME, then I add one layer of quality heatshrink on top of that.

That combo is good for lots of volts, current, temperature and joint rigidity

It's not cheap and you only get a tiny roll of the stuff that does not go as far as a roll of electricians tape.  :'(

Some brands may be half assed knockoffs, so far the best I've tried has been the 'SOS' badged one


FWIW, I'm not plugging SOS, unless the company wants to throw some benefits my way to finance a "666 uses for..."  vid on Youtube

and a battlers royalty percentage     :clap:



EDIT: Whatever you do ensure that the spade connectors are crimped properly and tensioned properly on the terminals for a tight fit

If they are physically loose or wonky when tested, heatshrink won't help much, except contain the sizzle for a while...  :scared:

 
« Last Edit: February 21, 2019, 11:25:23 am by Electro Detective »
 

Offline Zenith

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Re: Is heatshrink tube a good insulator?
« Reply #11 on: February 21, 2019, 11:14:14 am »

If no fingers or screwdrivers are going to be near it when it's powered on then heatshrink is fine.

If it's not going to be vibrating or moving around then soldering the connectotors is probably OK, too.

Yes, especially as it's for his own use and it's only for a short time. He's got insulated connectors and has the crimping tool on order.
 

Offline tautech

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Re: Is heatshrink tube a good insulator?
« Reply #12 on: February 21, 2019, 11:16:50 am »
Two layers of cheep heatshrink should cope ok with 230 volts.

or wrap a few turns of GOOD electrical tape (NITTO?)  and then a layer of cheep heatshrink on top


My current quick fix 'good enough' fav is that overpriced SOS silicone  ---stretch---   'repair' tape which seals itself to itself nicely.

If I want the job to not get done again for a LONG TIME, then I add one layer of quality heatshrink on top of that.

That combo is good for lots of volts, current, temperature and joint rigidity

It's not cheap and you only get a tiny roll of the stuff that does not go as far as a roll of electricians tape.  :'(

Some brands may be half assed knockoffs, so far the best I've tried has been the 'SOS' badged one


FWIW, I'm not plugging SOS, unless the company wants to throw some benefits my way to finance a "666 uses for..."  vid on Youtube

and a battlers royalty percentage     :clap:
It's called Self Amalgamating tape.  ;)

The powerco's used to use mountains of it. Make friends with some linesman and a couple of rolls will last you for years.
Avid Rabid Hobbyist
 

Offline Electro Detective

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Re: Is heatshrink tube a good insulator?
« Reply #13 on: February 21, 2019, 11:22:56 am »

I am assuming you refer to the Self Amalgamating tape old school stuff that turns to road tar after a time,
even fresh on the roll unused. Shelf life is nothing to do cartwheels over  :-- 

This SOS silicone stuff has none of the negatives afaict   :-// 

 

Offline tautech

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Re: Is heatshrink tube a good insulator?
« Reply #14 on: February 21, 2019, 11:27:01 am »

I am assuming you refer to the Self Amalgamating tape old school stuff that turns to road tar after a time,
even fresh on the roll unused. Shelf life is nothing to do cartwheels over  :-- 

This SOS silicone stuff has none of the negatives afaict   :-//
Never had any issues with quality self amalgamating tape....still using some I got 20 years ago off a linesman.

Maybe it doesn't like the OZ climate.  :-//
Avid Rabid Hobbyist
 

Offline totalnoob

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Re: Is heatshrink tube a good insulator?
« Reply #15 on: February 21, 2019, 12:40:55 pm »
The only way to be sure that HST is a good insulator is to test the insulation once its in place.  However, when I was running a 230V, 50 amp circuit for my welder, I was a little short in figuring my wiring length, so I went to Lowes and found a splicing kit for 6 ga. wire, it came with two layers of heat shrink tube to go over the splice connection.  The first layer is a thicker heat shrink tubing and the second layer is the more typical relatively thin heat shrink tubing.  Not sure if they have it in the size wires that you are using, but Lowes also had the heat shrink tubing separately in both thicknesses, but since I was dealing with large gauge wire I did not pay attention if they offered the thicker HST for smaller wire sizes.  Assuming you are in the US, if the HST is rated for 600V (i.e. meeting NEC requirements for low voltage applications) it should be fine regardless of what the thickness of the HST is.

Good luck,
Paul
 


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