Recommended advanced AC power for EU boats

[team karst]

Sure, if we now need to consider patient safety, with its very low mA ground currents and isolated ground conductors and lots of other stuff I dont know about, the rules will absolutely change to protect that one person at most all cost. Very much contrasting with the Navy view to protect the boat at all costs, even if there is an unluckly human at risk. Decidedly a different set of rules.

This has come up before in other discussions, but I dont recall the rationale. Why does the ABYC demand ship earth REF wiring even when using a perfectly acceptable isolation transformer feed?

As an aside comment. 240/120 split systems do use a neutral, and it is still a neutral when ungrounded. Yes, not a euro situation

[s/v Jedi]

Originally Posted by team karst

Sure, if we now need to consider patient safety, with its very low mA ground currents and isolated ground conductors and lots of other stuff I dont know about, the rules will absolutely change to protect that one person at most all cost. Very much contrasting with the Navy view to protect the boat at all costs, even if there is an unluckly human at risk. Decidedly a different set of rules.

This has come up before in other discussions, but I dont recall the rationale. Why does the ABYC demand ship earth REF wiring even when using a perfectly acceptable isolation transformer feed?

ABYC does not consider ships at all: it’s just for boats and yachts. Also, they don’t demand anything, they recommend. I believe they have now included the use of ground fault current devices for shore power, decades after ITU and the rest of the world started implementing them. I believe more details around isolation transformers is in the pipeline. I believe they only work with volunteers and just don’t have the man power to describe everything. They asked me a couple times but I am not compatible with their culture (volunteers come from corporations who have agendas etc.) I’ve done all that… a lot and I’m done with that. Instead I put some time in creating these diagrams and putting them here to grab for free.

[team karst]

Yeah, in summary, I don't think the removal of the ABYC N to E jumper on iso xfmr installs will hurt anything, and may even save lives. But, not all folks realize that a safety RATED isolation transformer is a special beast (low C from P to S, elevated hi pot rqmts, no P and S wire overlap, etc); and NOT the same as what the utility folks call an isolation transformer, to differentiate it from an auto-transformer. I currently have two feet in that industry. Expecting now the boat electricians to give me a talking to.

still think ground detectors would be good tho.

[Lyric]

How should the multiplus case ground terminal lug be dealt with? Have you connected all of the AC case grounds together without a connection to DC negative?

[s/v Jedi]

Originally Posted by Lyric

How should the multiplus case ground terminal lug be dealt with? Have you connected all of the AC case grounds together without a connection to DC negative?

The AC ground busbar is in the diagram posted at the start of this thread. You have a choice of how you connect the multiplus grounds, but you must make sure there are no loops.

I can work from memory but I still force myself to check this: take the multimeter and check all the ground terminals on the Multiplus: input and both outputs should all be connected and also connected to the big stud on the housing. When you have that confirmed, now you can plan the wiring:

I do one ground wire from each Multiplus, transformer, AC and DC metal breaker panel etc., preferably from the big stud and with an 8AWG wire, to the AC ground busbar. Next, during wiring of the input/output terminals, I do not include ground wires there. I prefer to use primary cable, i.e. one conductor. For most of this I use 8AWG, some like OUT2 only 10AWG

And indeed, I do not connect DC negative to AC ground. I have several DC negatives that are even isolated from each other to prevent damage during (near) lightning strikes.