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Joined: Dec 2001
Posts: 2,498
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I found a cool piece of old equipment. It's a fault voltage circuit interruptor intended to detect ground faults. It's got 2 ground connections, 1 for the incoming ground (auxiliary ground) and 1 for the load ground. If there was a voltage between load ground and auxiliary ground exceeding 50V it tripped. It's a 10x10x10cm box, still wired to a long piece of old NYM cable with the colors black, black, blue, grey and red. Auxiliary ground seems to be a long green wire.
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Joined: Aug 2001
Posts: 7,520
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That sounds like the old British voltage-operated ELCB (Earth-Leakage Circuit Breaker), commonly used as the ground fault protection in rural areas in the past ( U.K. Power Systems , diagram #4). There are still plenty of these in service in this area.
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Joined: Jul 2002
Posts: 8,443 Likes: 3
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Ragner, These units are still in use over here too. But our units have an arbitary value of trip @ 25VAC. Only used in areas, where the basics of the MEN supply can't be met, with respect to Fault currents (Earth resistance/Neutral Return).
[This message has been edited by Trumpy (edited 10-25-2003).]
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Joined: Aug 2001
Posts: 7,520
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These devices used to be the norm across large area of rural England, before PME was extended and before the current-operated ELCB became common-place.
They were required to trip at 50V maximum, but many actually trip well below that threshold. I've seen a few that will trip out on under 10V.
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Tom
Shinnston, WV USA
Posts: 1,044
Joined: January 2001
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