Monday, May 20, 2013

Making an extension lead, (socket end)

So I dealt with mains electricity a couple of weeks ago.

Now this is a quick post on how to put together an extension lead.

At the end of the post on mains power I was pretty keen to stress that there were colour codes associated with mains power, well, as it happens the cable that I was able to buy for my 3phase extension lead does not conform to that colour scheme.

The cable has conductors that are Brown Blue and black with a green and yellow earth conductor.

So to start,
The cable I'm making will be a 16amp three phase 240 Volt cable.

 That means a 4 pin blue "commando" socket is needed. There are fairly uncommon in the UK (as our 3phase tends to have 415 volts. quite uncommon in the US (where the three phases are 120volts) but apparently is quite common in Sweeden. so you can get the plugs you want.

I found these plugs (and sockets) by searching Ebay for IP44, and IEC 60309.

You can find these at screw fix, (where they are £11 for each plug -I paid £1 each for five on eBay) sockets are also available at screw fix, but again I found them cheaper on line.
(screw fix is a nationwide UK distributor of all sorts of trade type building materials, it's open to the public, so if you can't wait for an item to ship they may be the best bet!

So I'm going to start with he socket end.

Take the socket apart such that the back cover is away from the connectors,slide the back cover over the wire (with the open side facing the bare end) so that you'll be ready to seal up your connector later!
To remove the back of the socket use the two cross head screws that are located inside the grip portions.

Now take your 4 core wire and removing some of the outer insulation.
Then cut the phase leads to be shorter than the earth lead -the reason for doing this is that if the cable were ever put under strain and connections were to come out of the plug then the equipment you;re using would stay earthed, the worst scenario for electricity would be using a piece of equipment that was unearthed, that malfunctioned and became live, then you're the path to earth! By leaving the earth lead with some slack in to you're able to know that safety can be maintained, even if the cable has been put under such strain that conductors have started being pulled from connecting plug pins!
Now open up the cable clamp on the blue half of the connector and attach the wires into the holes indicated, with the brown black and blue wires being the phase wires and the green and yellow being the earth wires.
Then close up the cable clamp.

Now slide the back of the lead into place.
you can see a large black rubber washer, (it's about a half inch thick).

This is what seals the unit from weather (that and the little black o-ring on the other end)

Once you've gotten the back in place and screwed down, slide the final part of the back into place.
 this screws down squashing the rubber washer forcing it to grip the cable and provide a waterproof seal.

Finally, you have a lead with a socket on the end.

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