[time-nuts] Line Voltage - USA

Mark Spencer mark at alignedsolutions.com
Wed Jan 4 11:06:38 EST 2017

Hi David.   I've been told that in Canada the residential supply voltage in a neighbourhood is often set to account for the voltage drop in typical residential branch circuits. 

The last time the supply voltage in my home was checked it read 125 volts from each "service pole" to neutral or 250 volts from service pole to service pole.   The voltage on most of my normal branch circuits was typically 122 volts or so.   The minor issue for me is that I had a number of dedicated branch circuits using larger than normal wire installed that only served one load each so the voltage drop on those circuits was negligible.

(I also had the electrical service upgraded which involved larger supply conductors to the house which in turn would also have had less voltage drop.)

Good luck.

Mark Spencer

> On Jan 4, 2017, at 5:41 AM, Dr. David Kirkby (Kirkby Microwave Ltd) <drkirkby at kirkbymicrowave.co.uk> wrote:
>> On 4 January 2017 at 09:34, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
>> --------
>>> Do you have a reference to this +6%? I've heard from various sources that
>>> the UK is 230 -6%/+10%.  If the EU dictates otherwise, then I'm certainly
>>> over the 6% limit. I may or may not be over the 10% limit.
>> There was a transitional range, but I belive it has expired.
>> In 240V countries it was -6%/+10%.
>> In 220V countries it was -10%/+6%
>> --
>> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> I measured my voltage overnight in a peak hold at 255.10 V RMS as close to
> the meter as I could. One of the phases goes via a 100 A switch to the
> garage. I measured on the input of that switch. At 230+10% the maximum
> permissible is 253 V, but mine went to 255.10 V. That was measured on a
> Tektronix DMM916 (40,000 counter) meter, which has not been calibrated
> since I bought it new about 20 years ago.
> I spoke to a friend of mine who worked at the CEGB. He thought I might have
> a tough time getting the electricity company to do anything about 2.1 V if
> it was expensive for them to do.
> I was going to report my findings today at
> http://www.ukpowernetworks.co.uk/internet/en/power-cuts/report-it/report-general-issue-form/
> but having spoken to him, I think I'll monitor for a few more nights and
> see if the problem gets worst than 2.1 V outside the specification.
> The specification of the meter is +/- 0.7% + 4 counts, so measuring at 253
> V (maximum permissible mains voltage), the meter specification is +/- 1.81
> V, so there's no doubt that a measurement of 2.10 V above the maximum with
> a meter that's not recently been calibrated, is a bit on the dubious side.
> Perhaps I need something a bit more convincing before reporting this. I was
> thinking of buying a Keysight handheld, but whilst some are cheap, anything
> with a reasonable amount of functionality is quite expensive.
> Dave
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