joe6789 avatar image
joe6789 asked

How to wire neutral and ground when "splitting" the panel for Multiplus 2000?

Trying to install a Multi Plus Compact 2000w in my RV. The shore power connection has four wires: two 50A hot legs (red and black), neutral, and ground. Since the Multi Plus inverter will only power one hot leg, my plan is to "split" my existing breaker panel so that one leg (about half the panel) is powered direct from shore power and the other leg runs through the Multi Plus.

Let's say I leave AC line 1 as the non-inverter side, going straight from shore power into the breaker panel. Then AC line 2 would go from shore power, to the Multi Plus AC-in, then from the Multi Plus AC-out to the second leg of the breaker panel.

But how do I wire the neutral and ground?

Normally AC line 1 and 2 share a neutral and ground (since 1 and 2 are out of phase, their currents cancel each other out on the neutral). But now line 2 gets sent to the Multi Plus while line 1 goes straight to the breaker panel. Is it fine for the neutral and ground wires to simply follow line 2 through the Multi Plus before arriving at the breaker panel? Or does line 1 now need its own neutral/ground? Do I need to split the neutral so that one neutral wire follows AC line 1 into the breaker panel and another neutral wire follows AC line 2 through the Multi Plus? If so, do I need to isolate the two neutrals by cutting the existing neutral bar in the breaker box?

I've read that a better solution is installing a sub-panel, but I'm trying to go for the simplest solution, which I believe would be keeping everything in the existing breaker panel.

Advice would be much appreciated.

Multiplus-IIwiringGroundingwiring diagram
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joe6789 avatar image joe6789 commented ·

I'll add that this method of creating two breaker panels within the one existing box is described by Jack Mayer here:

Scroll most of the way down to the "Splitting" a 50-ampere Load Center section.

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rstarr avatar image rstarr commented ·
How didn’t you end up wiring this? I have the same setup only I ran the shore power into a breaker box and tied my neutrals and grounds there. I’ve had some wired issues where the Multiplus will reject the incoming power intermittently and started digging more into wiring. I’ve also seen where some people have run the neutral directly from shore power into the Multiplus and then to the load center.
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1 Answer
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @joe6789

You'll have to separate the neutral, the part powered by the Multi needs the neutral to go through the Multi, the other part you need to branch of before the multi.

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