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Hi - hoping someone can help with the question below, thanks in advance for your time.

We're looking at an installation before the FIT goes away, and discussing our needs with a couple of installers.

The complication - we're in an old farmhouse with 3 phase supply. One phase is tapped off for the house - and it's from this phase that all our consumption comes. The other two phases aren't used at all, although there's a (old) single meter across all phases before the house phase is separated.

We've looked at two options. (1) Install a single phase 4kw array and attach to the phase used for the house. (2) Install a 3 phase 10.5k array to benefit from the higher export / generation credits given that this is still allowed under G83.

What's not clear to me - assuming we go for the larger option, how can this be configured / connected such that aside from the FIT tariff, the total generated energy is offsetting our consumption, which is on the single phase.

It may be as simple as "the meter will automatically reflect this as it looks at total net consumption" - but my concern is that we go ahead and then discover that actually we're only getting a third of the estimated savings because the generated power on the other two phases doesn't 'offset' the consumption on the phase.

This didn't feel like a unique situation - from google I saw a couple of similar questions on this site asked a few years ago, but with no clear answer. I wondered whether there is a solution / standard approach.

Many thanks in advance.
Ok I did this in France. I decided to use the phase for the house as that's where the majority of power consumption was used. However, at the meter there was only one meter for the total consumption. So I doubt it would have made any difference in my situation. I did actually witness the meter going in reverse several times which was nice :) This was an old installation by the way and I'm not sure if the same would apply to a newer meter showing a reading for each phase.
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@ John - thanks for the quick response.

Some extra detail if helpful as others are looking ...

The meter is a GEC type E43B3b-RH, dated 1993. It has 2 counters - 'low' and 'normal' - no separate metering for individual phases. It has a 'reverse running protection' icon on the front.

From an old post on this site I'd seen this guidance

which appears to suggest that the meter should be operating on total consumption and generation. But it's not completely clear and I'd welcome any real life confirmation.

The scenario then is e.g.

Phase 1 - no consumption, 3.5kw generation and export
Phase 2 - no consumption, 3.5kw generation and export
Phase 3 - 10.5kw consumption (say), 3.5kw generation and export

I should get FIT tariff for 3 * 3.5kw.

But will I be paying for (10.5kw-3.5kw) = 7kw on phase 3 or (10.5kw-3*3.5kw) i.e. 0.

Thanks again!

Deleted member 26818

Quite a big difference between being paid for 3.5kW and giving the DNO 7kW for free and being paid for 10.5 kW.

I think you should contact your supplier and ask them, because it may be that different supplier’s do things differently.
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