So my new Phoenix 1200/12 by default has a floating neutral. I understand inside you can reconnect to have a bonded neutral, and from what I read, all larger inverters from Victron come default with a bonded neutral
Given that a bonded neutral means that my RCD/GFCI works when I touch only one wire, it seems safer. But I feel a bit unsure to essentually connect one of the two 230V wires to the hull of the boat. As well as wonder why Victron does not do it by default.
Any advise, suggestions, considerations?
(no shore power, fully off-grid iron hull narrowboat)
The rule is that the neutral is bonded to safety ground at only one point. So it depends on the system surrounding the Phoenix. If something external to the Phoenix connects neutral to safety ground, then you do not want to do it internally. If there is no external connection, then you should make that connection inside the Phoenix.
A Multi or Quattro has a ground relay on its output. When the grid is connected and passing through to the output, then the ground relay is open and the neutral to safety ground at the grid’s service entrance makes the single point connection. When the grid disconnects internally, the Multi/Quattro also closes the ground relay to make the neutral to safety ground connection because the one provided at the service entrance no longer makes it’s way to the output.
Edit: I thought of a 2nd reason why Victron may choose to float the neutral on the smaller invertors. The smaller ones typically come with “normal” sockets, like Schuko (EU) and Nema (US). And while UK is properly polarized, and US is “somewhat” polarized (not all plugs you may use are), Victron’s home turf of Schuko plugs is decidedly not polarized.
So a double bonding would not just give parasitic loops, but it could even cause a dead short, if both ends are grounded and you flip the Schuko plug.
Anyway, mine has a IEC socket, to be used in UK. So I better pay attention to the correct polarity.