On Tue, 19 Jan 2016 16:25:13 +0000, Chris Hogg wrote:

You'll have to wait for BST to kick in before you can do this, but sit
up on change-over night and watch the meter while some high power
item, like a kettle or fan heater is running.

How is having a load or not on the normal supply going to show
anything(*)? The meter measures kWhrs they don't change only the
cost. The meter should have flag of some sort to indicate which
register is being incremented but that'll change at zero or full
load.

(*) One would assume that those with E7 also make best use of what is
otherwise expensive electricity by haveing storage heaters. They'll
be on the switched supply and them coming in will make the meter spin
somewhat quicker or make the LED flicker...

The fact that old E7 meters like ours and your old one weren't
designed to be changed for BST suggests that the grid isn't really
that sensitive to precisely when E7 switches in and out.

The only thing that E7 gives you is 7 hours out of every 24 at cheap
rate. An individual supply will (should...) be fixed but across all
E7 supplies tere is a spread from about midnight to 0200 for the
start. The grid would have a problem if all E7's switched on at
precisely 00:03:42... it doesn't have problem with E7 switching over
a period of time.

I say should as our mechancial time switch stops during power cuts so
the off peak period slowly slides through the day depending on power
cuts.

--
Cheers
Dave.