My boar have VICTRON lithium batteries system connected to VICTRON Quatro. I would to like to install a backup support, for the supply of AC power from the grid, if the Quatro stop working and I don’t have chances to repair or replace this unit. Any help?
What kind of Quattro do you use on your wild boar boat? 
Otherwise, it would be the same as in this post…
Of course, this applies to your AC input from the mains connection from AC In2
The switch MUST, of course, be adapted to the power of the Quattro.
The article was about a Hager with a maximum current rating of 40A!!!
Quattro 5000VA
Felisberto Almeida
How high is your shore power connection fuse rating?
The 40A Hager could be sufficient here… otherwise there is also the Hager HIM 406 up to 63A, for example…