Changing inverter - implications for MCS and G98?

[Nick Thomas]

Let's say someone had, uh, theoretically, changed from a 3kW inverter to a 3.6kW inverter. The initial install was all MCS certified (so good for getting paid for export), properly notified to the DNO via a G98, etc, etc.

 

Does swapping out the inverter invalidate the MCS certificate? Does a new G98 need to be made?

 

*cough* asking for a friend, obvs *cough*.

 

And to extend into a hypothetical theoretical future, how about adding another 2.4kW of solar panels to the inverter later? Does that have any MCS implications? (I'm sure it wouldn't affect the G98, as it's all DC-side)

Edited December 2, 2022 by Nick Thomas
add hypothetical

[Nick Thomas]

Weirdly, looking at the MCS certificate my, uh, friend, has, it lists each individual roof hook and panel, but doesn't list the inverter explicitly. It does say that the "total installed generation capacity" is 3kW, though, despite listing 3.6kW of panels.

 

 

[Dillsue]

I dont think you would need to send a fresh G98 for an inverter change as your staying within the G98 limit that youve already notified them of. Youre probably obliged to let them know about the change so just email them a copy of the ENA type test cert for the new inverter.

 

As you say, additional panels are on the DC side with export limited by the inverter so the DNO isn't bothered. MCS is a different matter!

 

There were some changes to the OFGEM rules in the last few years. For a FIT system you can add panels but will only get FIT payments on the original FIT registered TIC. So if you had a 4kw system and upped it to 5kw, youll get paid 4/5 of whats generated. If youre on metered export the additional panels need to be MCS installed to get paid for export. You can install extra panels yourself but can't get export payments, for the extras, without an MCS cert. Seems that metering could get a bit messy if you want to mix MCS with non MCS install. I'm sure the OFGEM guidance will explain it all so Google it