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By chance, I ran into a video about a guy ranting about mains plugs used in Britain.

In the video, he shows how they are wired as well. So this got me intrigued and I watched a few others.

In all examples shown, flex cables' wires are:

  • Cut very short, and
  • Squeezed by screws (not cut longer and circled around the screw)

What is the reason for this?

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  • Please post a link to the video so that we can see what his specific objections were to the UK-style plug.
    – Niall C. ♦
    Commented Oct 9, 2014 at 15:20

2 Answers 2

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It might be important to add a photo of a plug, so us Yanks can understand what you're talking about.

enter image description here

Based on the image it's clear to see that the terminal screws have no heads, so it's much different from most screw terminals a US user would come across. Terminals like this; even in the US, are designed to clamp a straight bit of wire. With a terminal like this, wrapping the wire around the screw would not allow the screw to clamp the wire at all.

enter image description here enter image description here enter image description here

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    I added some photos to show how the stranded wire is clamped (the earth wire in this case, I pushed the pin back so it can be seen better), please delete any or all you consider superfluous.
    – RedGrittyBrick
    Commented Oct 9, 2014 at 17:46
  • Nice one... I had similar in mind for my answer, but didn't readily find the photos to illustrate my point.
    – John
    Commented Oct 9, 2014 at 18:38
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Screwing the conductor into the terminal in the plug gives a much more secure and resilient connection.

A longer wire wrapped round has the potential to work loose (then you could get arcing or even no connection) and also to potentially contact a different terminal. If the earth wire were to find a connection to the live terminal, you could end up with a metal case becoming live with 230 volts.

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  • "Screwing the conductor into the terminal in the plug gives a much more secure and resilient connection." - This is the opposite opinion of everything I've read on this site. Also it makes no sense - how could wrapping around the screw and squeezing the wire with the screw be more secure/resilient than only squeezing?
    – BlueRaja - Danny Pflughoeft
    Commented Oct 9, 2014 at 13:46
  • It's down to how the screws are arranged in the plug. They are (at least in every plug I've wired) designed to take the conductor under the "point" of the screw connector. As you describe it would make more sense if the connectors were designed to take the conductor under the head of the screw and if that were the case, I'd agree with you. However, the heads of the screws just aren't sized to trap the conductor.
    – John
    Commented Oct 9, 2014 at 14:18
  • Even in the US we don't just wrap stranded wires around screws, because it isn't a secure way of attaching them. The only way around that is to use a crimp connector or solder the ends of the wires.
    – Brad Gilbert
    Commented Oct 9, 2014 at 17:05

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