question

Depends on your settings. If you want to be able to charge with the full 120A you need around 3000W of input power. That would require a 16A hookup when using 230/240V. Based on your 'shoreline' and '50A rated' i'm not sure if you have 240V, or only 110/115V. In those case you need to double-up the ratings.

Also, these don't include any running loads. So if you want to power the loads as well, while maintaining the 120A charge you're going to need more. With a 64A socket you're good, but I don't know if thats available everywhere. I would suggest fitting a 64A socket (based on 110/115), and have the adaptor cables to connect to lower shoreline hookups as well.
With the Multi control or the bluetooth dongle you can adjust the shore input power so you don't overload a smaller shoreline. (the Multiplus will reduce the charge current if needed, and/or will assist the loads so the shoreline is not exceeding the set amps)

Hi DJSmiley

Thanks for your reply.

I am on a 230 V supply.

So 16 Amps therefore I’ll upgrade to 32 Amps, which is much higher than my shoreline MCB, at the moment. Great also that you mention i can adjust the current draw to prevent tripping the supply.

Great response.

Sean

There are two sizes of CEE plug for 230V single phase, 16A and 32A. Both blue. They're not interchangeable. You really need the 32A feed for your multi. The red ones are 400V three phase, but you will be limited to a single phase, so it's a poor option.

Not sure what the marinas will have, so suggest you get a 32A as you have decided, but also an adapter so you can plug into 16A. Cables must be rated for 32A so a minimum of 4mm2. Don't forget the galvanic isolator.

If you set the input current as @DJSmiley said and it's inadequate for loads, power assist kicks in and supplements from your batteries.

On hookups with a 32A connection you can use the full 32A off course