Heat Shrink for USB A and USB C - Sizes?


just wondering if anyone who has done heat shrink on USB cables, namely on USB A (the usb port for laptops/computers) and USB C.

im not sure what sizes on ebay i should purchase, ive asked various sellers but they pretty much give out those generic one liner responses (hello, thanks for your mail, plz check description, thanks).

i measured my USB C end and the circumference is about 30mm? and the USB A end circumference is under 40mm. online calculator says a 30mm circumference is about 0.37 inches (is this about 3/8 inches?) or under 10mm (9.5mm).

does phi mean diameter?

32pcs x φ3.0 x 40mm is 3cm in diameter?

pic of frayed USB C end https://imgur.com/a/qQxUCUs.

can anyone suggest a size to get? otherwise i might fork out to get those 300+ pieces 500+ pieces of heat shrink on ebay.


  • Have you considered either self fusing tape or Sugru? both make a good option for cable repair.

    • i've just watched a video abou sugru, never heard of it before will compare if its cheaper / easier than heat shrink

  • I suggest you get some electrical tape to re-enforce the area then use heat shrink.
    There are two common types of heat shrink, one that halves in diameter and one the shrinks to 1/3 it's diameter. The cheap heat shrink is the one that shrinks to 1/2.
    Saying that the diameter you buy is before it shrinks.

    I would go to a jaycar store and buy both the tape and heat shrink before you snap some of the wires and while you are there buy a replacement USB cable as it WILL break.

    • alright thanks, will check out jaycar. i have an abundance of usb cables just wanted to protect them all before they start to fray like this one.

      i think i tried normal tape / electrical tape before but it didnt wrap up too cleanly so it ended up looking quite ugly…

  • does phi mean diameter?
    32pcs x φ3.0 x 40mm is 3cm in diameter?

    Diameter is normally signified by Ø, but phi looks pretty much the same.

    I would expect the units to be the same if unspecified, so I think your example is a 3mm (un-shrunk) diameter.

    • yeah thought ph might be diameter, just wanted to double check.

      if φ3.0 is diameter of 3mm (unshrunk) then its mighty tiny, i dont think it would even fit through a usb c cable head. ive asked for clarification with some sellers so i'll see what they say. thanks for your input

      • its mighty tiny

        eh, 1.5mm is a common size when joining single wires

        i dont think it would even fit through a usb c cable head


  • try a hot glue gun

  • Try Jaycar. You can see what size you need.