Standardisation of Mains Voltages

[Dai Corner]

I came across a thread in a Bristol-based history/nostalgia Group on Facebook in which members were discussing the change from 210v to 240v in the late 60s / early 70s. Apparently appliances were swapped out area by area and people moving house encountered difficulties if their kit was the wrong voltage for their new abode.

I'd have been about ten at the time and took a keen interest in all things electrical but have no recollection at all of this exercise, assuming it had been completed well before I was born in 1960.

Does anyone remember this? Did retailers have to stock two versions or reconfigure appliances before sale? Did they get involved in the swap-out process?

Did repairers have to check what their customers' supply voltage was and use transformers if their own was different? Did modifications bring them work?

[Dave Moll]

As far as I recall, I grew up in the 1950s with 240V mains, though I didn't have anything with which to measure it back then. Certainly, anything marked with a voltage said 240V.

[barrymagrec]

Back in the fifties in the Beaconsfield area various places were still on 200 volts. My Dad had a Radiospares "Hygrade" auto transformer which he used to power the 200 volt sets which came in for repair - I still have it.

Beaconsfield itself changed in the very early fifties, apparently an electricity board chap came round with a big box of bulbs and other bits to swap out, of course most households had only a few items in those days.

[David Simpson]

Dai, if you look back through "Search" you'll find heaps of info on this subject. It's been discussed in great detail in several thread posts.

Regards, David

[ex 2 Base]

I don't know any thing about Bristol area, but generally there was a lots of different supply voltages and frequencies 40Hz. Some supplies were provided from coal mines and was DC. I have a copy of "Electricity Supply in the United Kingdom" which lists the changes 1269 to 1985. It makes interesting reading in date order, as the power from batteries, to steam engines to turbines which drove the generators is mentioned. The first fluorescent lamp was around in 1934 and now its on the way out. Ted

[JonSnell]

I grew up in the 50s and we had 220v DC until 1954, then 250v AC with no earth from a 2pin 2 or 5Amp socket or a 15A round pin socket with an earth to the water pipes.
Mother used to do the ironing, listen to the radio and light the lounge from the same bayonet ceiling rose!
Fuses were tinned copper wire and a piece of asbestos cloth to quench the spark.
Now they say we have a standard EU voltage of 230volts at 50HZ but it is actually 240v in the UK and 220volts in France. The actual EU specification is 230v +10 -20%.
Most newer Fender amplifiers wired "For UK Mains" are set at 230volts and over run the heaters and HT, causing short valve life and excess heating/dissipation.
Do they know what they are doing ... makes one wonder sometimes.

[paulsherwin]

There were still a few nonstandard voltages around in the 60s, but I'm surprised somewhere the size of Bristol was still on 210V by then.

[Dave Moll]

Originally Posted by JonSnell

The actual EU specification is 230v +10 -20%.

Although yes, it's +10%, but it's -6% not -20%.

[MeerKat]

The voltage here is usually 245-250 and 253 is not unusual, in fact my solar system continuously monitor the voltage and at 7 this morning it was 253.3 volts.

[G6Tanuki]

I remember in the 60s a family-member living in Nottinghamshire had mains that was 200VDC, with the +ve pole earthed. The next-door house had 200VDC with -ve earthed; there was one 2-core metal-clad cable to the 2 houses, with each core supplying one house and using the metal armour for the 'centre tap' earth-return. Everything was wired 2-core, there were no earths.


Here today my mains is typically in the 252-254V range - I've only seen it dip down to 245V on a few occasions.

[Herald1360]

ISTR Worcester was on 200Vac when I was a youngster. It converted to 240Vac sometime in the late '50s early '60s (at any rate before 1966 when we left). Most of our lightbulbs were 220V and a bit dim, it was already difficult to find 200V ones.



There were visits from the "Electricity Board man" (MEB presumably) who dispensed replacement lightbulbs and "converted" other items of domestic equipment. With hindsight, I suspect this was often just a relabelling exercise on any non adjustable obsolete appliances. After all, they were old and outmoded and if they failed a few weeks/months later they might well be replaced by a new one bought in the MEB shop!

[Graham G3ZVT]

Originally Posted by G6Tanuki

I remember in the 60s a family-member living in Nottinghamshire had mains that was 200VDC, with the +ve pole earthed. The next-door house had 200VDC with -ve earthed

As I have no memory of ever seeing DC mains, I have some questions.
What sort of plug & socket was used?

Was it an advantage for a radio to be in a -ve earth house?

A set clearly won't work with the wrong polarity, but could any damage result?
(I'm thinking of a leaky metal rectifier).

There would be no hum, but were there any other, perhaps more annoying artefacts?

Thanks!

[Tim]

I remember my dad telling me a man from the Electricity board came round and made an inventory of all the electrical appliances in the house. They returned sometime later with 240 volt versions of the relevant heating elements etc. and changed them all out. Anything that spares weren’t available for was replaced at the board’s expense.
Presumably they also set voltage taps etc.

[G6Tanuki]

Originally Posted by rambo1152

As I have no memory of ever seeing DC mains, I have some questions.
What sort of plug & socket was used?

Was it an advantage for a radio to be in a -ve earth house?

A set clearly won't work with the wrong polarity, but could any damage result?
(I'm thinking of a leaky metal rectifier).

There would be no hum, but were there any other, perhaps more annoying artefacts?

Thanks!

The plugs/sockets were ordinary 2-pin BS546, in 5 and 15A flavours. It didn't matter whether your house was on the +ve or -ve 'phase' - the plugs/sockets were unpolarised so if your AC/DC radio didn't work you unplugged at the wall, turned the plug through 180 degrees, and off you went!

The big problem with the low(ish) voltage was tellies: while there may just have been enough voltage to power the series-connected heaters, HT was at best marginal, and anything causing a voltage-sag would perturb the scanning oscillators so you'd get picture-roll for a minute or so.

I gather the [valve] HT rectifier in tellies was often jumpered-out, so the forward-voltage-drop disappeared and the heater-voltage for the rest of the valves in the series-chain was increased too.

[Megatron]

Originally Posted by rambo1152

As I have no memory of ever seeing DC mains, I have some questions.
What sort of plug & socket was used?

Was it an advantage for a radio to be in a -ve earth house?

A set clearly won't work with the wrong polarity, but could any damage result?
(I'm thinking of a leaky metal rectifier).

There would be no hum, but were there any other, perhaps more annoying artefacts?

Thanks!

later on post war a lot of legacy DC mains was provided via the national 50Hz grid and arc rectifiers. I have a brown brothers catalgue from 1939 and it has a section of mains filters. one filter is described as being suitable for removing arc rectifier Buzz from sets powered from Rectifier derived DC mains.
I guess this would be mainly 300 and 600 Hz from 3 and 6 phase rectification.

[paulsherwin]

DC mains came from a wide range of sources before the grid was established. Some towns had municipal power stations, but often the supply came from large local factories or mines, or even the local tram network. Some of these supplies must have been pretty noisy. They were mostly used to power lighting at first, so the noise wouldn't have mattered.

[dglcomp]

As I understand a lot of the supplies were what the business supplying it required, hence the wide range of voltages/frequencies.

[Brigham]

Aunt Elsie's cafe (Transporter Bridge Cafe) had DC mains, presumably from the Bridge lighting circuit, and was the first domestic property in Port Clarence to have electric light.
A decade or so later, the new workers' housing in nearby Billingham had AC at 40 cycles, unmetered, and included in your rent.

[Dave Moll]

Originally Posted by Andrew64

... at 7 this morning it was 253.3 volts.

Originally Posted by G6Tanuki

Here today my mains is typically in the 252-254V range...

Given that 230V+10% is 253V, both of these supplies, if the measurements are accurate, are going outside the permitted tolerance, albeit only slightly.

[G6Tanuki]

Originally Posted by Brigham

A decade or so later, the new workers' housing in nearby Billingham had AC at 40 cycles, unmetered, and included in your rent.

The +/-200V mains I referred to upthread was courtesy of the NCB pit [where my relative was the geologist]. Residents of pit-villages back then could choose to get 'free' electricity or 'free' coal [not really free, it was funded by taxpayers] as part of their employment.

There was much uprage and outroar when the National Grid assumed control and the old pit-provided DC mains were replaced by --metered-- 240 Volt AC electricity!

I vaguely remember a similar scheme from London, where workers on the Underground could be connected to the Tube-specific power-stations-of-the-day at a preferential rate. Some of the voltages involved in this were distinctly strange!

I remember that trains often used 80-Volt lightbulbs!