Unknown Domain

Parts: Plug

The last thing I looked at was the power cord, but equally important is the plug and it’s fittings, strain relief, etc…

Unfortunately power plugs don’t seem to be so much of a fashion statement as the fancy chrome plates sockets, and fabric sheathed cables that adorn them. This means that most plugs are just ugly plugs, but there are a few clever ones out there which a maker might choose over the standard cheapie.

Most plugs in UK high street shops seem to be manufactured by Masterplug, so there is a rather limited and duplicated set of products from various suppliers including, Homebase, B&Q, Screwfix, and Robert Dyas.

HDPT13O

Masterplug have three ranges of standard UK three pin plug, the first is their heavy duty model (HDPT13), which is available in black (HDPT13B), white (HDPT13W) and orange (HDPT13O). It is 13 amp rated and as the picture shows, it has a chunky rubberised finish with good side grips. This retails for £3.

 

PT13B

Next up is their rather ordinary looking PT13 model which as you can see comes in black (PT13B), or indeed white (PT13W), which seems to be the most common in the shops and retails for £2, it has a glossy finish and is very plain and cheap looking.

PT13HW

The last in their product line is an interesting one as it has a special grip at the back to make it easier to remove. PT13H comes in white only (PT13HW) and has the same cheap nasty glossy finish as the PT13 but has a ‘ring pull’ to make it easier for those with difficulties gripping to pull it out, especially useful if the pins get bent as can happen sometimes. It retails for about £2 also.

The Other End

At the other end of the cord will be a connector as well, as there is no cord retract on this model it makes sense to make it easier to put the cable away at the end of use, or to help routing it around things for a more permanent installation in a makers shed. What we commonly think of as a ‘kettle lead/cord’ actually has a far more boring, but technical name… ‘IEC 60320 C15’.

To break down what IEC 60320 C15 is I did a bit of research… IEC stands for ‘International Electrotechnical Commission’ who are a body who deal with the specification of international electrical standards to make things more compatible. IEC 60320 is one such standard, specifically it is for a non-locking electrical power coupler, i.e. a socket and plug for powering devices. The specification is specifically designed for home and office use, as it specifies sockets for up to 250V @ 20amps (in some cases).

Within the IEC 60320 standard are a number of different types of connector for different purposes, from your traditional 2 pin electric shaver C1/C2 coupling rated for a mear 0.2 amps, a three pin cloverleaf shaped laptop power supply C5/C6 coupling, and the widely used figure-8 connector on a radio called C7/C8. Through to the even more common C13/C14 connector used on a home computer and the confusingly similar C15/C16 connector used on heated appliances  especially older kettles, where the difference is simply the maximum temperature the cable assembly is rated for, and a small notch to prevent a ordinary C13 plug being coupled with a C16 socket where the heat could melt the plastic of the C13 plug leaving exposed live wiring, or shorting out whilst powered. At the top end there is even a C19/C20 used on the back of a Mac Pro and other high end computers mainly, which is used for high power appliances where a traditional C13/C14 assembly wouldn’t support the current requirement.

There is an interesting part of this IEC 60320 standard which is that C17/C18 are actually two pin versions of the common kettle cord, and among the many places such as Xbox’s they are commonly found on vacuum cleaners. Indeed some commercial/industrial use machines have this, and vacuum cleaners commonly aren’t earthed as they produce so much electrical noise and have no exposed metal surfaces to ground. The C17/C18 coupling isn’t easy to get hold of and is pin compatible with a C13 cord, but not the other way C14 and C18 because this would leave the earthed product unearthed.

In the spirit of this project I will use the most commonly available and accessible coupling, the C13/C14 pair, there are a few varians of the C13 plug, not least straight, horizontal right-angle, and vertical right-angle. You can also buy panel mounting sockets too.

c14-socket

Panel mounting socket

Straight plug

Straight plug

c13-hr

Horizontal right-angle plug

Vertical right-angle plug

Vertical right-angle plug

It would seem logical to make use of the vertical right angle plug, or horizontal right angle plug in this design to avoid it being pulled out by accident, the cable could come down along the body of the vacuum cleaner and through a metal retention clip like below:

Retention clip

Retention clip