230v Mains: Internal
The overlap with the 230v Mains: external is that they both take power from the inverter via a fuse box. There the fuse box feeds two internal circuits. The extension connection goes to the previously used three gang flying extension, now pretty much fixed to the wall and a 6A fuse that feeds a line to a) a junction box from where a cable goes through the wall to a 2 gang socket,
b) feed to another junction box to a 2 gang socket installed above the tool bench, and also
c) feeds a third 2 gang socket in the corner of the computer desk.