Why Strain Relief Matters

It’s late at night on an unfamiliar street, where I have just driven out to help a friend change a flat tire. Of course, the donut is deflated too but, not to worry, I have my trusty Slime brand compressor.  I plug it into the 12 V cigarette lighter and roars to life, only to start to sputter. Only by continually wiggling the cord could we inflate the tire and send my friend safely on her way. The symptoms of poor engineering were familiar.

I dissembled the plug and found the wire connected to the positive terminal (connected to the tip) sparked, melted and disconnected and the negative wire hanging on by a few strands. While I am sure Slime has thought about the mechanism of their pump, it’s obvious that no one considered the reliability of the humble plug, despite proudly mounding their logo onto it.  It’s failing are multiple: