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#114660 - 05/30/03 09:16 AM British violation?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
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?
[Linked Image]

[Linked Image]

The full story can be found in the Non-U.S. area here.


Tools for Electricians:

#114661 - 05/30/03 02:05 PM Re: British violation?  
CTwireman  Offline
Member
Joined: Feb 2002
Posts: 840
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

#114662 - 05/30/03 04:04 PM Re: British violation?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
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.


#114663 - 05/30/03 05:37 PM Re: British violation?  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
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).]


#114664 - 05/30/03 05:47 PM Re: British violation?  
Bill Addiss  Offline
Member
Joined: Oct 2000
Posts: 3,875
NY, USA
Paul,

That was quite a hint! [Linked Image]

[Linked Image]
Bill


#114665 - 05/30/03 06:14 PM Re: British violation?  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
I had spotted the individual conductor entries but just assumed that British power acted differently. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#114666 - 05/30/03 11:11 PM Re: British violation?  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,211
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

#114667 - 05/31/03 06:15 AM Re: British violation?  
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
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! [Linked Image]


[This message has been edited by pauluk (edited 05-31-2003).]


#114668 - 05/31/03 08:25 PM Re: British violation?  
David UK  Offline
Member
Joined: Oct 2002
Posts: 134
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.


#114669 - 06/01/03 06:05 PM Re: British violation?  
Trumpy  Offline


Member
Joined: Jul 2002
Posts: 8,211
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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