Re: energy in UK

On 2025-04-18 09:53, Liz Tuddenham wrote:

Carlos E.R. <robin_listas@es.invalid> wrote:
 

On 2025-04-17 23:11, Don Y wrote:

On 4/17/2025 1:44 PM, Carlos E.R. wrote:

Probably all of Spain has smart meters now. But the reason was, AFAIK,
that here the contract limits the current you can draw. For instance,
a contract can say that you can draw 15A (3450W). The meter has the
ability to switch off when you try to draw 16A for a time.

>
Wow!  Now THAT is interesting.  Here, the size of your service (ampacity)
effectively determines what you can use -- that, and your wallet.

>
I think that is an Spanish only feature.
>
They charge us for the watts we actually take, and also a fixed monthly
amount for the size of the pipe. Meaning, if we contract for a maximum
of 15A, we pay for that, €/month. If we contract 30A, we pay double
fixed amount per month. And the smart meter controls that we don't
contract 20 and take 21.
>
So people try to contract the minimum they actually need.

[...]
 Is there some time-averaging provision for high start-up transients,
such as motors would need?

Yes. The trigger is slow.

Is the metering based on wattage or current?

Before smart meters, it was certainly current, a slow switch triggered by heat or a magnetic field.  With smart meters I don't actually know.
The meters measure watts.

 The current draw of a multiple lighting installation in a shop may be
capacitive or the motors in a small workshop would be inductive and this
would determine the size of cables needed, so current-based netering
would make sense for that purpose.  The current wouldn't be
representative of the energy used, so wattage-based metering would make
sense for energy-consumption billing purposes.

I suppose current smart meters can also measure the power factor.
--
Cheers, Carlos.