PV and Economy7/10

[SteamyTea]

My 1987 vintage house has a separate consumer unit for the E7 storage heaters and DHW.  This is fed by separate tails from the smart meter.

All that is quite normal.

If I was to fit some PV, but with an 'islanding' inverter (and with a secondary safety grid isolator) and wire it into the E7 circuit, when the E7 off i.e. during the day, and the PV generating, would any of the power go back to the grid?

Does the time switch in the smart meter know not to export from the E7 circuit?

Edited September 3, 2023 by SteamyTea

[JohnMo]

Wouldn't the time switch be an circuit during the day and act as a breaker preventing a flow to grid?

 

 

[ProDave]

But at night, the islanded PV inverter would suddenly get connected to the grid for 7 hours.  Would that upset it, even if it is not actually generating at that time?

 

If you are going to do that, I would want a proper changeover relay to switch the storage heater CU between grid and inverter.

[SteamyTea]

21 minutes ago, JohnMo said:

Wouldn't the time switch be an circuit during the day and act as a breaker preventing a flow to grid?

I don't know, hence the question.

6 minutes ago, ProDave said:

But at night, the islanded PV inverter would suddenly get connected to the grid for 7 hours.  Would that upset it, even if it is not actually generating at that time?

Again, I don't know.

 

The problem could be overcome with PV diverters for each device, but was wondering if that was really necessary.

 

Probably easier, and more consistent, to dump load into a battery, then get the energy back out when there is enough charge.