Please direct your questions and comments here for discussion, regarding UK Power Systems Schematic Drawings #1 thru #4, located in the "Technical Reference" area under the topic:

UK Power Systems #1 thru #4

These drawings were created by ECN member "PaulUK", and re-drawn in AutoCAD format by ECN member "Nick". I just converted them from .DWG [AutoCAD file format], to .GIF format - then uploaded and posted them.
Special thanks should go out to these two members for their contributions!

Scott SET ... posted 10/20/2001 04:35:00

*Message edited to create hyperlink directed to schematics*

[This message has been edited by Scott35 (edited 10-20-2001).]

Well, I thought I proofread these drawings thoroughly. I just noticed I drew the neutral links as fuses.

Nick and Paul,

Great Job! Thanks to both of you for taking the time to present this to us!

Paul,

I've been meaning to ask, what type of 'armored cable' was used in direct burial of the old systems? Is there a similar product on the market today? Or, was that determined to not be a good idea (I notice it's not mentioned in any of your descriptions of more modern systems)

Bill

Nick,

Would you like me to fix this, then re-post the schematics?

Scott SET

Scott,
Yes. Thank You

My apologies for the delay in getting back to you all - Had a really busy couple of days.
*
Nick & Scott,
Thanks for taking the time to do these AutoCAD posts; much neater than my hastily drawn skethes.
I was going to mention the neutral links drawn as fuses, but you noticed it yourself anyway.
One other minor point: If you are trying to indicate the wire color codes accurately, the hot leg of the single-phase service cable to the house main fuse is always red, not the color of the phase it is connected to. (I drew all houses tapped off blue phase for convenience, although obviously the services are evenly distributed between the phases.)
*
Bill:
My thanks to you too, of course, for scanning and posting my original sketches.
The original underground cables had a lead armor and were then wrapped in some sort of hemp/bitumen compound. They can still be seen in older systems, but to the best of my knowledge are no longer made (too expensive, plus the modern paranoia about lead, no doubt).
Later cables used steel wire armor with a similar outer covering. Modern replacements are steel wire armor with a tough PVC jacket. (See SWA cable 6942X, 6944X in the TLC catalogue, pg. 14.)

P.S. In overhead distribution areas, single-core SWA-PVC cable is now commonly used for an underground service from the nearest pole. The armor is the concentric neutral, and in PME serves as protective earth as well.


[This message has been edited by pauluk (edited 10-21-2001).]

Scott,
Can we change the color too? I'll send you updated files today incase it saves you time.
Nick

OK, it took me a few days to get things going, but I have re-posted the UK schematics #1 thru #4 with the corrections [conductor color codes and Neutral links]. Corrections done by Nick.

In AutoCAD, I moved the text on the lower right side so the schematic[s] will fill as much of the "Zoom To" window, prior to exporting as .BMP and all that baloney. Those who are CAD users will understand this junk.

These drawings are great!!! Feel free to create more of them!!!

Scott SET

Looks good to me now.

By the way folks, 3-phase service to commercial premises follows the same basic arrangements as for 1-phase residential.

Obviously the meter is 3-ph and there are 3 main service fuses. A main 3-ph GFI can be found, although for large installations it's more likely there will be two or more "main" GFIs to avoid the whole lt going off if one trips.

The only other major difference for 3-ph is that the main switches and/or main GFIs are 3-pole and do not break the neutral.

I can't find the thread, but there was a discussion on power transmission and how a noodle/ground was needed. Here it is created on the premisis ( or close to it)

I'm not quite sure what you're getting at with "created on the premises." Do you mean that the neutral & ground effectively become separate after the bond at the main service panel or meter socket?

Paul,
perhaps I'm here...

All the pix show 'overhead lines' as red/yellow. There would seem to be no nuetral on the high side???

unfuzz me please...

Oh boy, I was starting to get confused here as well! When you said "Here it is created...." I assumed that "Here" was referring to the U.S.A., but I guess you meant the U.K. diagrams in this thread (I now THINK that's what you meant, yes?)

I couldn't quite figure what you were getting at about the red/yellow high side at first, but I think you must have been assuming that these were the high-voltage input to the xfmr. At least that's the only way I can interpret it, unless I'm missing something.

O.K., let's clear the confusion. The diagrams don't show the high-voltage side at all. The three xfmr windings are the secondary star windings of the low-voltage side, providing a 240/415V Wye output. Red, yellow, blue are the standard phase colors, black for neutral. So all four wires bracketed "Overhead lines" are the secondary xfmr output strung along the poles.

I showed the house tapped off the blue phase for ease of drawing, but some will be tapped red phase and others yellow phase. In many districts the same lines will supply 1-ph power for residential and 3-ph for commercial. As far as the basic distribution system is concerned, there are no separate xfmrs for 1-ph residential loads as in America (except for an odd remote house).

I thought leaving out the HV primary would simplify the diagrams; sorry if the omission has confused you!

The HV side of the xfmrs is almost always 11kV delta. The aforementioned single-phase xfmr for a remote house has an 11kV primary run to two legs of the 3-ph 3-w 11kV network.

Has that cleared the mists, or just made it worse?

Paul,
ok, so we have a delta/wye system. I had mistaken some of the wye secondary for primary ( a guy could get hurt making that mistake)....

sorry for the :confusion:

Phew! I'm glad that's sorted out!

Primary/secondary mixup.... Hmmm....I can just hear the customer now:

"But why can't I run my room heater on 11 thousand volts? Won't I get more heat?"