Per a suggestion found in a Victron manual, I am looking at installing a manual transfer switch that will switch the Supply Feed going in to my "critical load" sub panel... between the AC-Out of my Victron MultiPlus, and the Grid Supply.
The Manual transfer switch has an isolated breaker that will allow only the Inverter Output L1 or the Grid L1 to be connected at one time to the Load L1. If the Inverters fail, or are being worked on, the "critical loads" can be cut over so they are supplied directly from grid.
The problem I am having, and the question I am asking is: The Transfer Switch has a common bus bar for the Neutral. Is it safe to bridge together the MultiPlus AC-Out Neutral, and what is essentially the AC-Input Neutral in this manor when using a transfer switch?