UK LV Electricity Voltages 1954

[russell_w_b]

Related to the pylon thread and my comments about 230 / 240V, I dug a little further and thought the attached tables might be of interest. They are from Molloy's 'Electrical Engineers' Reference Book' (7th Edn: 1954) and list the electricity supply voltages in principal British towns as they were in 1954.

The key is on the 'London' page, but all supplies are 3-phase 50Hz (unless stated otherwise). Those with single numerals are single phase only, and numerals in brackets refer to d.c. supplies.

[hannahs radios]

Hi Russel I tried to download these but my tablet just says file format not supported can you show them a different way??

[russell_w_b]

Originally Posted by hannahs radios

Hi Russel I tried to download these but my tablet just says file format not supported can you show them a different way??

I'll scan them as PDFs sometime (bit limited at work!), but there are various freeware progs that will open .docx files. 'Free Editor' is one that works well.

[Andrew B]

Very interesting Russell.. It seems a lot of towns still had a heritage DC supply. The one thing that puzzles me is the "DC three wire", does this mean a centre tapped supply as in +200v 0v -200v ?.

It would be interesting to have the supply figures for 1925 to see how popular DC supplies actually were.

Andrew

[emeritus]

Interesting that, at the bottom left-hand corner of the London page, there is a voltage of 104 volts. I can't recall having come across any other nominal mains voltages that were not expressed as rounded to the nearest 5 or 10 before.

[ukcol]

pdf format

[Tim]

OOh, Southport had 110 Volt. I wonder why?

[hannahs radios]

That's it I can see them now thank-you for doing that

[russell_w_b]

Thanks, Colin! Saved me a job. Your bonus is in your next pay-packet.

[broadgage]

Originally Posted by Andrew B

Very interesting Russell.. It seems a lot of towns still had a heritage DC supply. The one thing that puzzles me is the "DC three wire", does this mean a centre tapped supply as in +200v 0v -200v ?.

Andrew

Yes, 3 wire DC was indeed a centre tapped supply an earthed centre wire or neutral.
The centre wire carried only a relatively small current and was often half the size of the outers, as the positive and negative conductors were known.

Voltages varied but were commonly in the 200 to 240 volt range from either outer to the centre wire, with twice that voltage between outers.

Homes or other small premises were connected between one outer (selected at random) and the neutral.
Larger premises had a 3 wire service consisting of both outers and the centre wire. This gave the option of a higher voltage supply, typically in the 400 to 480 volt range for heavy power.

The correct colour code was
RED=POSITIVE OUTER
BLACK=CENTRE WIRE
BLUE= NEGATIVE OUTER

For a 2 wire circuit derived from a 3 wire DC system the correct colour code was black for neutral and red for live. This led to confusion at times since many people expected red to be positive, when in fact in a house connected to the negative outer, the red wire was negative.

Astonishingly, the current IET regulations list the new colours for 3 wire DC !
BROWN=POSITIVE OUTER
BLUE=CENTRE OR NEUTRAL WIRE
GREY=NEGATIVE OUTER.

[ukcol]

Originally Posted by russell_w_b

Thanks, Colin! Saved me a job. Your bonus is in your next pay-packet.

Its exceptionally easy to convert .docx to .pdf in Word v14.
Just choose .pdf in the "save as" dialog and the Word document gets saved as a pdf.

I don't collect a pay-packet now (being retired) a cheque will be fine though.

Back to topic....

[TonyDuell]

I'll be a right anorak...

AFAIK Lynton lost its 100Hz power station in the floods in 1952, so by 1954 was presumably 50Hz.

[G6Tanuki]

In parts of the industrial East Midlands three-wire +/- 200V DC was common until the early-1970s. An ancient relative in Mansfield had this [supplied via "Walsall" outlets] which was an enduring problem for them because their rented TV [presumably expecting 240V and so rather marginal when faced with 200V] suffered from line/frame shrinkage and picture roll when other people in the area imposed loads and reduced the voltage.

They had an 'inverter' box to supply their [presumably AC-only] radiogram.

[JHGibson]

Thanks to Post #10, a 70 year old mystery has been cleared up for me. I see that our town, Leek, had DC mains but our side of the street must have been wired up with the common wire and the -230V wire. That meant that our DC Lotus All Electric 3 valve had a hot -230V chassis in order that the HT rail be positive WRT the chassis. That is why I would get a hefty shock from the slightly projecting grub screw on the reaction control.
John.

[Herald1360]

Interested to see Worcester *200/346 asterisked. I remember its being 200V (and the changeover to 240V) but had no idea about 3-phase supplies, let alone 2-phase oddities.

[russell_w_b]

Originally Posted by ukcol

Its exceptionally easy to convert .docx to .pdf in Word v14.
Just choose .pdf in the "save as" dialog and the Word document gets saved as a pdf.

Great Scott! So it is (in Office 2010 too). Thanks for that, Colin. Every day is a learning day!

[Peter.N.]

I have seen the voltage in parts of Petts Wood kent in the '50s down to 180 volts in the evenings, played havoc with the TVs.

Peter

[SteveCG]

I note that Cambridge is shown as being 240V. I am reasonably sure it was 200V until the early '60s. Pre 'National Grid frequency unification' days it had a frequency of 80 c/s.

[Hartley118]

AFAIK, parts of Bolton were on 210V until some point in the 1960s. I was living in a rather cold bedsit in Manchester in the late 1960s (on 240V) and my boss, who lived in Bolton, generously gave me his old 210V Ferranti radiant fire which had fairly recently been replaced by the electricity board when they increased the mains to 240V.

Boy did that 210V fire throw out a lot of heat on 240V!

Martin

[happytiger]

Originally Posted by broadgage

Astonishingly, the current IET regulations list the new colours for 3 wire DC !
BROWN=POSITIVE OUTER
BLUE=CENTRE OR NEUTRAL WIRE
GREY=NEGATIVE OUTER.

DC circuits in GB follow the same rules as AC, before the UK mess up.

RED =POSITIVE OUTER
BLACK = CENTRE or NEUTRAL
BLUE = NEGATIVE OUTER
This is the same as three phase AC kept for safety
RED= PHASE WIRE
BLACK NEUTRAL WIRE
BLUE= PHASE WIRE
YELLOW= PHASE WIRE
If you depart from these, you are introducing the EU colour code.
Of course you do not have to comply with any of this, but think of the person who has to work on it afterwards,and the danger of wrong connections.