Recommended advanced AC power for EU boats

[s/v Jedi]

This post requires some clarification:

It is valid for all power systems that have one phase and a neutral. It is not valid for US split phase, for which I will post a separate diagram later.

The shore power norm in the EU is 230V at either 16A or 32A. Victron has an isolation transformer for either option, but there are consequences to the choice:

- I never saw a 32A outlet anywhere. Of course they will exist somewhere, but they are very rare.

- The Victron 7kW isolation transformer is 230V in/out only. It does not allow you to change a jumper and connect to a US 120V outlet like the 3.6kW transformer does.

For above reasons I recommend to use a 3.6kW transformer with 16A inlet. But I also recommend to upgrade all inlet wiring incl. shore power cord to 6mm2 (10AWG) so that it can be adapted for use with a US 120V shore power outlet. This is why the input breaker is 32A even for a 16A inlet.

Do not worry about 3.6kW not being enough to run everything aboard: the inverter/chargers have Power Assist which can add 6kW for a total of more than 9kW of available power. The 3.6kW, added to solar power generated, must be enough for the average consumption so that the batteries get charged when power demand is lower.

An advanced AC power system like this used to be for the big boats. Today, with solar power, lithium batteries and electric galleys on the rise, it has become normal for boats from 12 meter (40') and up.

This diagram is not all that is needed. It assumes you have lots of power generation systems, mainly solar (recommend 1500W minimum to mostly eliminate genset use), aboard as well as at least a 10kWh 24V lithium battery. These numbers are based on my direct experience... which may change in the future as we only have such a system for 6 months.

The diagram has two 3kW inverters instead of smaller ones or one larger model. The total 6kW is required for the all-electric option and multiple units provide redundancy and price effectiveness.

There is an old fashioned manual transfer switch to change between shore power and generator. This switching is typically not done often, with the manual switch being much more reliable than an automatic transfer switch or a Quattro inverter/charger setup which have two inputs... at much higher price. The only reason to select a Quattro would be higher capacity.

There are three output busses. Two are familiar as they connect to OUT1 and OUT2 of the Multiplus units, where OUT2 only gets power when shore power or genset power is available.

This can be changed in case you want to operate the inverter/chargers independently instead of in parallel. in that case bus 1 becomes the output of the first unit and bus 2 the second unit. This setup has a powerful benefit: using the breakers around the inverter/chargers, one can be forced to only charge the battery while the other can be forced to inverter mode. This allows the use of 50Hz power aboard while connected to 60Hz shore power. If this is used often and/or full inverter power is needed, a third unit or just a battery charger can be added to the diagram.

Bus 3 is a bypass bus. This can be used like the OUT2 for power only from shore or genset but it's also useful in case of equipment problems.

The distribution breakers are double pole for additional safety as well as flexibility and future modifications.

I have examples of panels included. Note that single pole breaker panels can be modified to double pole and that panels with rotary switches are available as well. I don't have these panels yet but plan to have them custom fabricated by online services that do just that.

[Thumbs Up]

Originally Posted by s/v Jedi

This post requires some clarification:

Yes it certainly does. The diagram is showing a fully floating A/C distribution system with no fault monitoring system.

[s/v Jedi]

Originally Posted by Thumbs Up

Yes it certainly does. The diagram is showing a fully floating A/C distribution system with no fault monitoring system.

The diagram shows how every 230V/50Hz boat with isolation transformer is wired. It is the recommended configuration and conforms to code.

Please take your fight against isolation transformers elsewhere, it is not appreciated here and I will ignore it from here on. Make your own thread about the danger of the isolation transformer.

[Thumbs Up]

Originally Posted by s/v Jedi

The diagram shows how every 230V/50Hz boat with isolation transformer is wired. It is the recommended configuration and conforms to code.

Please take your fight against isolation transformers elsewhere, it is not appreciated here and I will ignore it from here on. Make your own thread about the danger of the isolation transformer.

I have nothing against isolation transformers. I am challenging this statement:

It is the recommended configuration and conforms to code.

Conforms to which code? Code of the Jedi "Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet the Force."

As I said in the other thread, if I am wrong about this I will admit it. I believe that the recommended configuration for isolation transformers on a boat is to tie your outlet ground wires and chassis grounds back to neutral or L2 on the isolated side. I even posted the manual for your transformer. Now you have run off and started another thread trying to extoll the virtues of your configuration without explaining the anomalies. The way your system is configured makes it so that your outlet safety grounds won't play nice with grounding wire referenced neutrals. You have a fully floating output. This is great for hospital operating rooms and possibly Jedi warriors but they normally include expensive fault monitoring devices which you have not addressed.

[Jammer]

Interesting. I don't think you'll ever use bus 3 except for testing and experimenting.


I think you could simplify considerably. Ditch the input breakers on the inverters and just use a rotary off-shore-gen switch for each one, and get rid of bus 3 and the associated breaker. Hardware everything to the shore/invert output from the inverter and just shut off the water heater when you don't want it to run off the inverter.

There, I saved you $3000 and left you with a system that's just as safe and just as functional, as a practical matter.

[s/v Jedi]

Originally Posted by Thumbs Up

I have nothing against isolation transformers. I am challenging this statement:

Conforms to which code? Code of the Jedi "Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet the Force."

As I said in the other thread, if I am wrong about this I will admit it. I believe that the recommended configuration for isolation transformers on a boat is to tie your outlet ground wires and chassis grounds back to neutral or L2 on the isolated side. I even posted the manual for your transformer. Now you have run off and started another thread trying to extoll the virtues of your configuration without explaining the anomalies. The way your system is configured makes it so that your outlet safety grounds won't play nice with grounding wire referenced neutrals. You have a fully floating output. This is great for hospital operating rooms and possibly Jedi warriors but they normally include expensive fault monitoring devices which you have not addressed.

It conforms to code world wide. The isolation transformer ties output neutral to ground and the inverters trigger a relay that connects neutral to ground during inverter mode. You are so focused on fighting this that you don’t realize it actually does what you say it doesn’t. You get to post your mantra in the US version, where I take out this behavior and make a floating 120V as well as a floating 240V.

In no case ever is L2 to be grounded. It is dangerous, probably trips breakers but potentially kills.

[s/v Jedi]

Originally Posted by Jammer

Interesting. I don't think you'll ever use bus 3 except for testing and experimenting.


I think you could simplify considerably. Ditch the input breakers on the inverters and just use a rotary off-shore-gen switch for each one, and get rid of bus 3 and the associated breaker. Hardware everything to the shore/invert output from the inverter and just shut off the water heater when you don't want it to run off the inverter.

There, I saved you $3000 and left you with a system that's just as safe and just as functional, as a practical matter.

My diagram is for maximum function, reliability and safety... minimum cost... not so much. That said, your proposed changes limit functionality dearly:

You must have input breakers for the inverter/chargers, it is code. Also, the breakers are much cheaper than an additional rotary transfer switch.

Bus 3 main function is a bypass. One example: this allows you to have AC power available while programming the inverter/chargers. I’m pretty handy when it comes to troubleshooting and getting things back online, but I once made a mistake when an inverter failed, which backfed power from shore into the genset output, killing it’s residual magnetic field, taking that out as well. This mistake was possible because wiring was messed with. With the setup with these switches and breakers, all such problems are avoided, greatly adding to reliability.

I fixed that genset by flashing the field with a 12V battery... was interesting

Eliminating 3 breakers makes no difference in the initial investment.

[alaskanviking]

Originally Posted by Thumbs Up

I believe that the recommended configuration for isolation transformers on a boat is to tie your outlet ground wires and chassis grounds back to neutral or L2 on the isolated side.

The way your system is configured makes it so that your outlet safety grounds won't play nice with grounding wire referenced neutrals. You have a fully floating output.

No! You tie your neutral and ground back to the neutral/ground of the source of power.
With a generator it ties back to the generator.
If you only have shore power, it ties back to the output of the dock/marina transformer.
If you have an isolation transformer it ties back to the output of the isolation transformer
If you have an, autotransformer than it ties back to the autotransformer

It's not a floating ground. I see it clearly connected to the isolation transformer and generator.


However the shore power inlet is labeled to take N (230v) or L2 (240v). using L2 would make it floating. I don't think that's a concern with a European system, you just take the ground from the inverter charger output. 230v euro ECFI/GFCI would work in this setup. If you use a 240v breaker in a split phase system your only using L1 and L2 anyway


Jedi's system as shown is the correct way to do it for a 330v system

[goboatingnow]

ISO small craft AC code is the designated neutral output of the isolation transformer is tied to the down stream protective earth to facilitate fault current return to the transformer

It’s questionable whether a protective earth in a isolation transformer is needed at all given that the return path is solely via the neutral. In houses it exists because “earth “ is a return path , with an isolation transformer only the neutral is a return path

[Lasseman]

Very intresting! Your design goals "maximum function, reliability and safety"... i only agree on maximum function part, more "functions" yes but at the cost of lots more complexity.

Reliability, meaning two smaller inverters instead of one bigger maybe. But greater chance two things breakes then one i say.

Safety, i dont agree at all. Nothing more safer in your design compared to for example one larger Quattro default standard design. I dont see your design as "faulty" or "not to code", its just over complicated in my view.

I am thinking of an Quattro 5kva install in my boat, so im intrested learning more.

[Lasseman]

Originally Posted by goboatingnow

...It’s questionable whether a protective earth in a isolation transformer is needed at all given that the return path is solely via the neutral. In houses it exists because “earth “ is a return path , with an isolation transformer only the neutral is a return path...

In the "ISO 13297 Fourth edition 2014-12-01" standard (i think is the latest), makes it not questionable at all...

section 4.6
Metallic housings or enclosures of permanently installed a.c. electrical appliances shall be connected to the protective conductor system in the craft.

and section 3.7 defines
protective conductor
protective grounding conductor
conductor, not normally carrying current, used for some measure of protection against electric shock,
for electrically connecting any of the following parts of electrical equipment to the craft’s ground (earth)
and to the shore a.c. grounding conductor through the shore power cable:
a)cexposed conductive parts of electrical equipment;
c) the main grounding (earthing) terminal;
e) the earth point of a source, or an artificial neutral
b) extraneous conductive parts;
d) earth electrode(s);

[s/v Jedi]

Originally Posted by Lasseman

Very intresting! Your design goals "maximum function, reliability and safety"... i only agree on maximum function part, more "functions" yes but at the cost of lots more complexity.

Reliability, meaning two smaller inverters instead of one bigger maybe. But greater chance two things breakes then one i say.

Safety, i dont agree at all. Nothing more safer in your design compared to for example one larger Quattro default standard design. I dont see your design as "faulty" or "not to code", its just over complicated in my view.

I am thinking of an Quattro 5kva install in my boat, so im intrested learning more.

I’m sorry but your assumptions are incorrect. A safer system than what is in this diagram doesn’t exist. If you bring it down to one inverter, you don’t gain nor loose safety... you loose redundancy.

Also, two Multiplus 3000 units in parallel function exactly like a single 5000 unit except you have more power with the two 3000’s. This configuration is fully supported by Victron and in use worldwide. You can install many systems in parallel.

Your inverter/charger will fail, the only question is when. The chances of two parallel units failing simultaneously is minuscule compared to having just one unit. This mechanism of redundancy has gained consensus worldwide and is in use everywhere.

Complexity: if this diagram is too complex, then do not install it. Hire a professional to do it for you and to show you exactly how to use it, how to reprogram the Victron’s in case you want to go from parallel back to independent units or just one unit when the other failed.

I am fully confident with this diagram and if you want to point out what you think can be done better then please go ahead but be specific so I can address it. Just saying “one unit is better” isn’t really convincing...

[tanglewood]

Originally Posted by s/v Jedi

Also, two Multiplus 3000 units in parallel function exactly like a single 5000 unit except you have more power with the two 3000’s. This configuration is fully supported by Victron and in use worldwide. You can install many systems in parallel.

Paralleled Victron inverters may not be as redundant as you expect. They have to be configured as parallel devices, and once that is done, both expect the other to be present and operational. If either inverter fails, the survivor will not operate until it has been manually reconfigured as a stand along inverter. With the proper adapters, software, and computer you can get the survivor back on line, but the system doesn't "just keep running" when one fails. It all stops working until you "fix" it.


With at least one other inverter manufacturer, you can lose a slave and the other(s) will keep running uninterrupted. If you lose the master, a reconfigure is required, but it's done through the control panel, not through adapters and software. So you only have a possibility of a service interruption rather than a certainty.

[Thumbs Up]

Originally Posted by s/v Jedi

It conforms to code world wide. The isolation transformer ties output neutral to ground and the inverters trigger a relay that connects neutral to ground during inverter mode. You are so focused on fighting this that you don’t realize it actually does what you say it doesn’t. You get to post your mantra in the US version, where I take out this behavior and make a floating 120V as well as a floating 240V.

In no case ever is L2 to be grounded. It is dangerous, probably trips breakers but potentially kills.

Apologies for the confusion between this diagram and the one for your boat. To be fair though this diagram does not clearly specify a neutral ground connection (or lack of it).

As far as L2 output from the transformer is concerned, Your transformer's two output connections are labeled L1 out, and N out. L2 is neutral. Neutral is jumpered to ground (unless you have floating distribution as on your boat). With split phase (L1,N,L2) you are correct in saying that L2 is never grounded.

For an even safer system you could denote the isolation transformer output breaker as a GFCI.

[Thumbs Up]

Originally Posted by goboatingnow

ISO small craft AC code is the designated neutral output of the isolation transformer is tied to the down stream protective earth to facilitate fault current return to the transformer

It’s questionable whether a protective earth in a isolation transformer is needed at all given that the return path is solely via the neutral. In houses it exists because “earth “ is a return path , with an isolation transformer only the neutral is a return path

But as you point out is required by code. Removing it (the output neutral/ protective earth connection) would create a floating distribution system (IT) as in Jedi's boat, hospital operating rooms, ship controls etc. An IT system on a boat has arguments for being safer but includes some caveats (mainly fault detection) that should be addressed.