Seems like a good thing. I was at a mate's house who'd just had a load of
solar panels installed. He reckons he'll get an 11% return on his
investment. I was quite impressed watching the disc of his electric meter
Apart from tying ones money up and the aesthetics has anyone here got
experience of this scheme good or bad?
Perhaps different suppliers use different forms. The one I had
from Scottish Power clearly required equipment data and MCS
installation reference, which are only available after
The actual question asked is if, since installation, the meter
has moved backwards.
Chris J Dixon Nottingham UK
AIUI, no new disk meter for the last twenty years or so has run
backwards. There is a simple ratchet mechanism to stop Scousers
applying dodgy power factors to fool the meter.
AIUI, meters older than this have now been circulated out of service.
If it has a disk, It will run backwards.
My washing machine controller is a disk - it won't turn backwards (without
Just because it appears that something might run backwards, doesn't mean
that it will (and as it's in a case, unlike the WM, there is no way that a
"normal" person could test the leccy meter)
Well you're clearly a top barrister and can make bold statements based on
very little information.
His meter is like a mechanical mileometer in a car and has a horizontal disc
about 60-70mm in diameter. I saw it spinning backwards.
It turned several revolutions in the short time I watched it. Me being
mildly cynical and to check that it wasn't going in the 'supposed to'
direction got him to flick the kettle on and sure enough it went in the
other direction albeit slower. The solar power would easily cope with a
kettle but with other appliances on....
There is something I didn't quite understand. I think this is it: With old
meters they can't tell how much solar electric being used and how much is
being exported so it is split 50:50. You get paid for all units generated
but and extra 3.5p on the exported.
Yes that is correct but also even normal standard modern digital meters
will not display the exported power so the assumption of 50% export
continues to be applied.
From what i have read about these meters is that internally they DO
measure exported power but have to be interrogated electronically (via
the two led windows) to get at this information.
Meter readers are not provided with the equipment to read them
The simple digital meters do however, have an indication that power has
The display alternates between the import reading and "rEd" which stands
for 'reverse energy detected' and was originally there to catch people
who try and run their meters backwards to defraud the leccy co.
Also when power is being exported, the red light which usually indicates
1 Wh of consumption per flash, lights continuously.
It will be interesting to see the reaction of the next human meter
reader who calls, as my meter now indicates "rEd"
As my supply company is different from my solar export company, I cannot
imagine that they will have talked to one another about me having a PV
It can be even worse than that, as has been discussed in a very
long thread on:
To summarise, some Siemens meters (and possibly others) are
capable of being programmed so that any reverse power is added to
power consumed, and displayed as the only reading visible. This
option was clearly chosen by somebody as an anti-fraud measure,
but then forgotten about.
It seems that the power companies themselves do not fully
understand this, even when explained to them clearly and
repeatedly. Of course, they know best ;-).
As a result, it is quite possible, as explained at length on the
forum above, for solar panels to increase your bills
significantly. Don't get caught out!
Chris J Dixon Nottingham UK
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