Total RCD Protection?

22 Apr 2008
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United Kingdom
I've just returned from living in the south of Spain where all the circuits in the consumer units are protected by one isolator and one RCD. I think this is because all of the supplies are overhead and the supplier doesn't supply a earth. Each supply goes to a metal pylon or similar on your property and that itself is earthed as an electrode into the ground. I think (but not attall sure) that this is called a TT system in the UK? Does this type of total protection apply here in the UK if no earth is supplied or can a split load be installed, with some not on RCD protection? I ask because i found that in a small nuisance fault situation everything was disconnected losing the lights and defrosting the freezer if i was away from home.
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It's not compliant with 7671, but you do see older installations with a 30ma RCD acting as a main switch. Should have 100ma time-delayed RCD as 'main switch' protecting lights and a 30ma RCD to protect sockets etc. Do you have a 30ma set up now you're back home?
You must have RCD protection on all circuits if it is TT. You can use a split CU if the "non-main-RCB" circuits are protected by RCBOs.
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Depends on how good your earth electrode is, it all about disconnection times in the event of a fault. I've worked TT systems where there is no need for RCD protection under the 16th edition.

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