question

Johan Houwaard avatar image
Johan Houwaard asked

what breakers for multiplus 2 ac-in output

I am installing a multiplus 2 to store solar energy and don't want the ESS function. I have a 3 x 25 amp 230 volt grid connection and want to use one phase to connect the multiplus 2.

This fase is extended to the barn where I want a fuse box with 3 16 amp groups, a 4000 watt solar inverter and the multiplus 2 connected to it. What ac brekers should I use for the extended fase and the multiplus two, I am using only the AC IN to load and unload the 20 kwh set of E-BOX 48-100 batteries

Multiplus-II
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3 Answers
sharpener avatar image
sharpener answered ·

What size Multi? Also a diagram would help.

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Duivert NL avatar image
Duivert NL answered ·

hi you have to calculate selectivity in your fuse system, so if grid is 3x 25A everything connected after that must be on a 16A breaker, the distributor in the barn can be on a 3x 16A breaker in your main fuse box

but if you want to distribute with another breaker panel in the barn everything behind that can be max 10A…

So you could run the multi on one of the 3x 16A wires that comes from the main fuse box, but you cant go higher..


I suggest you contact an electrical installer if your not familiar with electrical systems


3 comments
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davefromnl avatar image davefromnl commented ·

In a system with only the grid you would be right. But Johan has 3 power sources (grid, PV and MPII. In his case, he needs to plan the cable sizes and size the breakers accordingly.
I would advise to consult a specialist. Your local installer will probably have no experience with a system like this.

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Duivert NL avatar image Duivert NL davefromnl commented ·

He wrote he is only using ac in on multi and not ac out, so breakers need to be all calculated to grid size

There is not nothing different or special in his system then others, grid, PV, multi, he wants to use the multi in grid parallel


You cant have a 3x 25A grid with 25A breakers in your system, you could blow the main fuse, 20A is possible but depends on local rules in NL you need 16A after a 25A main fuse

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Johan Houwaard avatar image Johan Houwaard commented ·

Only one phase is going to the barn, so i can put a 25 amp breaker for that phase in my main fuse box. The modbus in de fuse box in the barn is connected to the main fuse box, three 16 amp breakers (one for the pv) and the Multiplus t2 5000. I will never feed my battery power to the grid, so the high amperage will never be in the cables, only in the busbar, right?

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thesmok avatar image
thesmok answered ·

The circuit breaker primarily protects the cable behind it, so it should be selected for the rated current of your cable run.

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