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Stephen Johnson avatar image
Stephen Johnson asked

Protecting Multiplus Outputs - GFI breakers needed?

I am reading the manual for my Multiplus 3000W/12V/120VAC inverter charger. The manual says that both of the AC outputs need to be protected, but the English wording is ambiguous and differs for AC-Output-1 and AC-Output-2. It is regarding a solar-powered RV application, where I am using AC-Out-1 for the existing AC panel and AC-Out-2 for a new shore-power-only panel that supports the air conditioner, hot water heater, and refrigerator. The manual says ground fault circuit protectors are needed, the salesman at my dealer says they are not, but he also didn't know there was a second AC out or understand what it was for. If GFI breakers aren't needed, I can use the existing main breaker to protect AC-Out-1. Any help appreciated. I tried looking at the schematics on the Victron web site, but I don't know what the symbols in the circuit panel boxes mean.

MultiPlus Quattro Inverter Charger
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2 Answers
Paul B avatar image
Paul B answered ·

You should put breakers in that are lower than the maxium Pass through current eighter 16 amps or 50 amps depending on your inverter model (i Suspect your model is 50 amp version)

Its upto you and your local law requirements as to or if you also want to install anything for additional safety.

otherwise using the existing b reaker should be fine as long as its smaller or equal to the pass through amps

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fallguy1000 avatar image fallguy1000 commented ·

load breakers have nothing to do with the requirement for earth leakage breakers

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steve-carter avatar image steve-carter commented ·
Are you saying that GFCI's aren't needed for safety? Can you expand on that? I'm just trying to clarify the intent of your comment. I'm no expert - I'm less concerned with electrical code than safety.

Thank You!


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Kevin Windrem avatar image
Kevin Windrem answered ·

Certain outlets in the RV will need GFCI protection, usually based on the outlet's proximity to water (bathroom, kitchen, etc.). Inserting an inverter between the shore power inlet and the outlets changes nothing in terms of the requirements.

Overcurrent devices are generally sized to protect wiring and other components down stream of the breaker. But they can also be used to protect the supply from exceeding that capability. For a Multi, the AC out 2 has a maximum current spec however the AC out 1 does not and can be assumed to be the AC input rating plus the inverter's power assist capability. If you load the AC out 1 to that limit and simultaneously load the AC 2 output to it's limit, chances are you'll overload the inverter or trip the breaker on the Multi's input. So you need to give some thought about the system as a hole and assign breaker sizes accordingly. If this confuses you, it would be best to speak to a system designer/installer. Your seller should be able to help locate one.

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