Extending earth wire
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lindt
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Extending earth wire

by lindt » Mon Jul 18, 2011 7:56 pm

I am in the process of replacing some old plastic 13A sockets (which didn't require earthing) with new metal ones (which require earthing). Unfortunately, the earthing wire has been cut short by the previous owner and there is only a short stub of single core earthing wire coming out of the insulation. I need to use a small plastic connector block to extend the earthing wire, but I am unsure what amp rating of connector block I should use.

As the earthing wire only carries a short burst of current when there is a fault before the breaker trips, can I use a 5A connector block on the earthing wire or do I need to use a 15A one?

Also, is 1.5mm^2 single core earthing wire suitable for this purpose or does it need to be thicker?


Any replies would be greatly appreciated. :)

ericmark
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by ericmark » Tue Jul 19, 2011 10:39 am

There has never been a time when 13A sockets did not have earths connected. Light yes but never 13A sockets.

To find wires too short rings alarm bells. Using a crimp the wire can be extended and 1.5mm sq is the normal size. But you need to test the earth as normally you will get two cables to each socket and the cables loop around in a big circle. So if not connected in two sockets then all sockets may have no earth.

There are testers google socketandsee and test4less and under electrical then general electrical and socket testers you will see a array of testers from £12 to £90. The Socket & See SOK34 Easy Socket and Earth Loop Tester will do a reasonable job at £30. The Kewtech Loopcheck 106 Socket Tester also does same thing at £40 as does the Martindale EZ150 Loop Check Plug tester at £45 but the cheap Martindale CP501 Check Plug at £12 don't do a loop test so do not really test the earth well enough.

Of course may other outlets where you can buy these, but do make sure they do a loop test. Even these do not really do a A1 job at testing and really proper testers start at around £220 for the Kewtech KT41 Digital Loop/PSC Tester. Also using the testers can cause danger and you need to know what readings to expect. When one starts to look at £220 just to test then one must ask is it worth it? And really I would think getting an electrician to inspect and test is the way forward.

lindt
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by lindt » Wed Jul 20, 2011 7:32 am

Thanks for the reply ericmark.

Sorry, I don't think I explained myself very well. I was talking about the earth connection to the metal surround on the facia plate of the socket. Each socket has a working earth connection (to the top earth prong of the plug), it's just the actual front plate now requires earthing since it's now metal and I'm not sure what amp connector I need. :)

ericmark
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by ericmark » Wed Jul 20, 2011 9:44 am

1.5mm sq cable is fine. No need for connector it will just go in with the other two in main terminal. It is many years since I have seen a face plate which was not internal connected to main earth it is unusual to have to run link wires.

You will of course still need to test the socket and complete the minor works certificate that does not change.

Yes I know many DIY people don't test their own work. But that does not make it right.

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