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Joined: Aug 2001
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Here is a British 3-phase panel, on a 240/415V 4-wire wye service that is the U.K. standard. The load has since been removed, but do you see a problem with how it was wired? The full story can be found in the Non-U.S. area here.
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Joined: Feb 2002
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Paul, very intesting to see a UK style disconnect. Does the UK also use the US practice of the line=top terminals and load=bottom terminals? Is that the problem here?
Peter
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Joined: Aug 2001
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No, the line is going to the correct place (follow the above link for an explanation of the switch action).
The problem does lie with the way the feed has been brought to this unit, however. Look toward the bottom, and keep in mind that this is a steel enclosure.
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Joined: Apr 2002
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So the “MEM” switch enclosure of ferrous metal would cause an inductive-heating problem where the conductors pass through individual holes in the bottom of the can. 99NEC300-20 warns of this left of the pond.
[This message has been edited by Bjarney (edited 05-30-2003).]
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Joined: Oct 2000
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Paul, That was quite a hint! Bill
Bill
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Joined: Jan 2003
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I had spotted the individual conductor entries but just assumed that British power acted differently. Bob
Bob Badger Construction & Maintenance Electrician Massachusetts
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Joined: Jul 2002
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Hey Paul, If that's a Star circuit, where's the Neutral?.
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Joined: Aug 2001
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No neutral was needed here. The key-cutting machine which ran on this supply just had a 415V delta-connected motor, small enough to have direct-on-line starting rather than star-delta start-up. assumed that British power acted differently
Well, it drives on the left-hand side of the conductors and has an accent! [This message has been edited by pauluk (edited 05-31-2003).]
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Joined: Oct 2002
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OK, so the power drives on the left & has a British accent. But you still get eddy currents when each phase is passed thru separate KO's. This is bad practice whichever side of the Atlantic it is done! Also the open KO on top of the box should be fitted with a blanking grommet.
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Joined: Jul 2002
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Paul, The centre and right-hand wires look like they are going through a rubber grommet. But the left-hand one looks like it has been fed through a hole that has missed the grommet, you can sort of see a small piece of metal sticking up in front of the wire. Also, isn't the door on these units, supposed to have a seperate bonding wire on it from the body earthing terminal, to a terminal on the door?.
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