[time-nuts] And, for my next trick, 50Hz

[Steve Rooke]

Hi Chris,

2008/10/3 Chris Cheney <chris.cheney at tesco.net>:

> A bit of Googling finds:
>
> Frequency: "a variation not exceeding 1 per cent above or below the
> declared frequency;"
> (http://www.statutelaw.gov.uk/content.aspx?LegType=All+Legislation&title=e
> lectricity+safety+quality+continuity&searchEnacted=0&extentMatchOnly=0&con
> fersPower=0&blanketAmendment=0&sortAlpha=0&TYPE=QS&PageNumber=1&NavFrom=0&
> parentActiveTextDocId=1590332&ActiveTextDocId=1590368&filesize=4590 -
> section 27(3)(a))

Hmmm... that would make a mockery of keeping time on the large number
of  mains timed clocks in the UK. They would be out by a minute about
every hour and a half or a quarter of an hour each day, which would be
hopeless!

> Electric clock time: "NGET will endeavour (in so far as it is able) to
> control electric clock time to within plus or minus 10 seconds"
> (http://www.nationalgrid.com/NR/rdonlyres/4894C7AA-DCD2-4835-9986-
> 57338C31C86A/9922/BC3_i3r18.pdf - section BC3.4.3)

For some reason I could not get this link down, it just keeps stopping
about a third of the way through. The title does not give an idea of
the nature of the period for which the 10 seconds drift is acceptable.

> BTW wrt earthing via the incoming water main - in the UK, plastic pipe is
> commonly used for incoming water mains these days.

That is probably the case now so I guess they must put a local earth
spike instead. What I was trying to convey was that there was a local
earth at each house.

73
Steve
-- 
Steve Rooke - ZL3TUV & G8KVD
Omnium finis imminet