I have no idea what this part is called. I want to figure out if I can remove the wire out of it and slide in the other broken end before soldering it the board. Is it reusable, or do I need to buy another one? (e.g. because it's heatshrinked or something)

broken wire

  • \$\begingroup\$ It's a strain relief. \$\endgroup\$ – winny Mar 29 '19 at 8:37

You can reuse that strain relief.

Strip the insulation off the cable above the strain relief and then pull out the copper wire strands.

Then use a small drill bit and drill out each of the two halves of the cable.

Work your way up in drill size.

Use pliers to turn the drill bit.

Don't use a power drill unless you are very skilled with it.

The strain relief and the cable are usually made from different plastic, so it is easy to scrape out the cable insulation.

Once the strain relief is cleaned out, then pull new cable through. (or the undamaged old cable)

I have done this procedure few times myself.

enter image description here

  • \$\begingroup\$ Nice, the pin vise I bought months ago for no particular reason will finally come in handy :) \$\endgroup\$ – AgentRev Mar 30 '19 at 9:14

Found it, it's a "strain relief grip" and this one can't be replaced since it seems bonded to the wire.

Source: Securing electrical cables to holes in enclosures?

  • 2
    \$\begingroup\$ Strip the wire and reconnect then mold your own strain relief with liquid rubber or LePage's "sub-floor adhesive." PL400 or equiv Polyurethane. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 29 '19 at 6:17
  • \$\begingroup\$ @SunnyskyguyEE75 Would epoxy work? It's just a toy. \$\endgroup\$ – AgentRev Mar 29 '19 at 6:25
  • 3
    \$\begingroup\$ No. Epoxy is too hard. The ideal strain relief is graduated from 5x the stiffness to 1x the stiffness of the wire over a 10x bend radius of cable. As you can see this design failed this criteria and broke. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 29 '19 at 6:31
  • \$\begingroup\$ I see. The cable actually broke due to excessive pulling from a single event, the toy was bought a week ago. \$\endgroup\$ – AgentRev Mar 29 '19 at 6:41
  • 1
    \$\begingroup\$ There is additional stress whenever there is a major change in stiffness, and this becomes the weak link. Thus the graduated approach optimizes cable strength. \$\endgroup\$ – Tony Stewart Sunnyskyguy EE75 Mar 29 '19 at 6:43

Actually, there are standard strain relief parts offered, see example at Digi-Key, with the same function and without epoxy or other resin molding:

enter image description here

They also go under "cable gland" moniker.


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