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#114660 - 05/30/03 06:16 AM British violation?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
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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#114661 - 05/30/03 11:05 AM Re: British violation?
CTwireman Offline
Member

Registered: 02/07/02
Posts: 839
Loc: Connecticut, USA
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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#114662 - 05/30/03 01:04 PM Re: British violation?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
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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#114663 - 05/30/03 02:37 PM Re: British violation?
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
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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#114664 - 05/30/03 02:47 PM Re: British violation?
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Paul,

That was quite a hint!


Bill

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#114665 - 05/30/03 03:14 PM Re: British violation?
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
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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#114666 - 05/30/03 08:11 PM Re: British violation?
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Hey Paul,
If that's a Star circuit, where's the Neutral?.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#114667 - 05/31/03 03:15 AM Re: British violation?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
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.

 Quote:

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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#114668 - 05/31/03 05:25 PM Re: British violation?
David UK Offline
Member

Registered: 10/03/02
Posts: 134
Loc: Inverness, Scotland
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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#114669 - 06/01/03 03:05 PM Re: British violation?
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
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?.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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