Electrical tape vs heat shrink tube: safest? where's the data?

Thread Starter

rambomhtri

Joined Nov 9, 2015
308
Hi, I wanted to ask a quick question. When finishing a job with cables involved, you have to insulate them from the surrounds, so the copper cables are protected and people and animals are protected as well. I used to use electrical tape, any that you buy in a hardware store. Some years ago I improved my skills and tools, and though heat shrink tape was the best, most professional thing to do.

Nevertheless, the other day I asked myself:

Wait, how good heat shrink tape is compared to electrical tape in terms of insulation and safety?

Where can I see the data of insulation? I've never seen any warning, tape or tube, that says "CAUTION: use only under 1000V", or something like that. Thinking about it, it seems that the electrical tape offers way better insulation, but that's just a thought. The HST looks more professional when finishing something but since it's "so thin" compared to 3 or 4 turns of tape.

I mostly work with 240V wires, so the 1000V is just an example. I was just curious about which method is safer in terms of electrical insulation.
 

panic mode

Joined Oct 10, 2011
1,794
I see electrical tape strictly as a temporary measure - because inevitably it will degrade and come off. If cold, it does not stick. if hot glue starts oozing. Either way tape eventually unwraps or slips, while leaving mess behind. Whatever insulation grade this is equivalent to now, it is less than what one started with. Shrink tape is normally designed to fuse and make permanent solid mass (layers merge into one) so no unwrapping...
 

jpanhalt

Joined Jan 18, 2008
8,347
1) There is self-fusing electrical tape that I have had remain intact for at least 10 years in an outside conduit junction box. I use 3M brand. There are probably others. It is a durable rubber.
2) Heat shrink comes made with various elastomers. PVC is common, but you can also get nylon, Teflon, and neoprene (and maybe others). I have used neoprene for things exposed to weather. It has a good shrink ratio with only moderate heat compared to what is required for Teflon. I use it on battery and heavy duty cables, such as 2-0 welding cables.
 

MaxHeadRoom

Joined Jul 18, 2013
19,466
What I do in highly moist or wet conditions is fill the heatshrink with RTV and then shrink the tubing before the RTV sets, then let it dry.
You may want to use heavy wall H.S. type.
Max.
 

SamR

Joined Mar 19, 2019
1,509
I use shrink wrap that has the "goo" already in it. Have had spliced cables submerged in seawater last for years. Downside gotta remember to put it over the wire BEFORE terminating. There is only 1 good electrical tape, 3M self-vulcanizing rubber tape and it's not cheap. Not as durable as shrink wrap but you can't use shrink-wrap on "odd stuff" like wire nuts etc. For extra durability in abrasive or wet locations use multiple layers with each outer layer longer than the one below. The other downside to shrink-wrap is it's less flexible than taped joints. So I use both as the need arises.
 
Think of electrical tape as a crayon. It's used to mark the white wire black in the US when white is hot.

It really has no other use except maybe temporarily attaching a pull wire.

For tape as tape goes self-fusing silicone electrical tape, but it doesn't really protect.

heat shrink tubing and adhesive heat shrink tubing have their uses.

Can't say one item always works.
 
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JMW

Joined Nov 21, 2011
122
Whatever you use it must meet the specifications of the original insulation. This is both electrical and abrasion. Much heat shrink fails in the latter.
 

SamR

Joined Mar 19, 2019
1,509
Ahh I forgot the Liquid Tape. Use it for marine work doping ring or spade connections to prevent corrosion at the exposed points. Easy to peel/scratch off with fingernail to unscrew/bolt terminals but with only one good dabbed on coat or maybe 2 it is very durable and heat resistant.
 
Hi, I wanted to ask a quick question. When finishing a job with cables involved, you have to insulate them from the surrounds, so the copper cables are protected and people and animals are protected as well. I used to use electrical tape, any that you buy in a hardware store. Some years ago I improved my skills and tools, and though heat shrink tape was the best, most professional thing to do.

Nevertheless, the other day I asked myself:

Wait, how good heat shrink tape is compared to electrical tape in terms of insulation and safety?

Where can I see the data of insulation? I've never seen any warning, tape or tube, that says "CAUTION: use only under 1000V", or something like that. Thinking about it, it seems that the electrical tape offers way better insulation, but that's just a thought. The HST looks more professional when finishing something but since it's "so thin" compared to 3 or 4 turns of tape.

I mostly work with 240V wires, so the 1000V is just an example. I was just curious about which method is safer in terms of electrical insulation.
3M/Scotch - 'Super88' is specified at 600V per ply (Mean dielectric breakdown test EMF = 10kV) --- On an anecdotal note: In the 20+ years following application of said product, I've yet to experience failure (i.e. loss of adhesion, checking, etc) in unprotected outdoor applications w/ seasonal temps ranging from 160°F (71°C) in direct sunlight through -50°F (-46°C).

As regards 'heat shrink tubing' the germane specifications should be printed upon the product's packaging and/or available upon the manufacturer's website -- FWIW (Re: heat-shrink material) I strongly suggest polyolefin over vinyl for the former's' maintenance of elasticity following protracted age/exposure...

people and animals are protected as well.
Animals gnaw and people (especially children) are adept at 'forging pathways' to trouble!:eek: Protection of equipment (and, hence, life) against such 'attack' requires placement of the conductors out of reach (overhead or underground) or use of metallic conduit/armor...

Best regards
HP:)
 
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nsaspook

Joined Aug 27, 2009
6,610
All good stuff but you must also use armored waterproof cable too in some over-kill mil-spec applications. I helped to installed the computer systems on several of the BB recommissions in the 80's at the LBNS shipyard. We drilled through sometimes at least a foot of armor plating to run interconnects. All the cables were stuffed with monkey-sh-t' (“Compound, Stuffing Tube”) to make waterproof glands between compartments that were also blast-proof.
https://www.waywordradio.org/monkey_shit_1/
8f57da23e7a8e2284240f683981b8c49.jpg
 

JMW

Joined Nov 21, 2011
122
All good stuff but you must also use armored waterproof cable too in some over-kill mil-spec applications. I helped to installed the computer systems on several of the BB recommissions in the 80's at the LBNS shipyard. We drilled through sometimes at least a foot of armor plating to run interconnects. All the cables were stuffed with monkey-sh-t' (“Compound, Stuffing Tube”) to make waterproof glands between compartments that were also blast-proof.
https://www.waywordradio.org/monkey_shit_1/
View attachment 184704
Armored cable is required so BMs and GMs can sharpen their knives
 

Thread Starter

rambomhtri

Joined Nov 9, 2015
308
My question really was: if you have a ground cable and a 300V live one, what would you use to isolate one from each other?

The cables are together, that means they are separated by two coats of tube or tape, one for each other. Also, the cables don't have to resist abrasions or weather conditions.

What if it is a 1000V live wire? Would you still tube both cables and that would be good enough?

I guess what I'm asking is how many Volts per layer of tube or tape are supported. Which one isolates better.
 

MaxHeadRoom

Joined Jul 18, 2013
19,466
Using heavy wall heat shrink on the individual conductors and one H.S. to cover overall, each with RTV before shrinking should suffice, I have used this method on automatic well pumps etc.
 

be80be

Joined Jul 5, 2008
1,963
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