heat shrink tubing over heat shrink tubing

[csdave]

hi,
I am turning a bicycle in an e-bike by adding a mid-drive motor and a battery.
To connect the battery to a fuse box and a connector i am soldering the corresponding wires. i am planning to solder each wire (+ and -) with a heat-shrink tube around each. I would then like to put a bigger heat shrink tube around both wires to make a cleaner setup with both wires into a single cable. Is it a good idea to shrink a heat shrink tube on top of two other heat shrink tubes (one for + and one for -) or do I risk melting the inner tubes when I shrink the outer one?
please tell me if my description is not clear

thanks

dave

 

[andre_luis]

In general a quick hot airflow is sufficient for shinking the pipe not affecting so much what is inside. Anyway, I do not feel confortable on using it as the isolator, particularly in your case, where due to the shaking of the byke, this may subject the assembly to a repetitive attrition; I consider it to be only a finishing jacket, being the electric isolation as a 'plus' since it is not uncommon for these pipes to tear with any salient sharp tip of the weld or wire, but if you take proper care, it may work pretty nice.

 

[csdave]

I consider it to be only a finishing cover, being the electric isolation as a 'plus' since it is not uncommon for these pipes to tear with any salient sharp tip of the weld or wire.

thanks,
what should I put as isolation then? self-amalgamating tape? silicone grease?

underneath the heat-shrink sleeve on each wire? or over it?

Then if the wires are properly isolated using a heat-shrink sleeve on top of both the others should be fine, right?

 

[andre_luis]

If you ensure that the surface of the solder is smooth, I see no problem in using this tube as an insulator, but rather exaggeration, I would put more than one. By the way, except for hobby, in jobs where the cabling is subjected to a more severe environment, like its case where it could take rain, I would paint the peeled electric wires a pasty electrical sealing product, commonly called liquid insulating tape (eg https://www.amazon.com/Gardner-Bender-07315001126-LTB-400-Electrical/dp/B000FPAN2K).

 

[csdave]

thanks, just one thing, would you put the paste and the heat-shrink sleeve, or just one or the other?

 

[andre_luis]

thanks, just one thing, would you put the paste and the heat-shrink sleeve, or just one or the other?

I did it with both, I used the shrinking pipe just for finishing purpose in an application let's say more professional, once the pasty tape has an ugly look after it's cure, but if you heat the pipe along with the still fresh paste, in shrinking it will shape the paste, formatting it to the diameter of the shrinked tube. Just be aware that this will stiffen this section, losing the wire flexibility.

 

[KlausST]

Hi,

I see no problem in using heat shrink tubes as isolation.
In detail the datasheet should clarify this.

Klaus

 

[dick_freebird]

I've done this many times for the same reasons. You might
look at alternatives such as automotive wire-loom and strain
reliefs; you do not want your soldered lug connectors to be
the mechanical support as this can lead to metal fatigue up
near where the solder has stiffened the wire. Maybe just tape
the loom to the frame, that seemed to be normal-ish on the
old Japanese motorcycles I had. Just don't leave it to flop
and vibrate.