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hintzcm avatar image
hintzcm asked

50A in a 30A Camper to use Power Assist

I read I need to switch out my 30A breaker with a 50A for the Power Assist on the Multi-Plus. Is it safe to install a 50A main breaker in a 30A camper?

If yes, in the picture my original 30A breaker is on top. The new 50A breaker I’ll need to install at the bottom since it’s a double pull. Does it matter which leg of the 50A breaker I connect the black wire?
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powerassist
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3 Answers
cleaver avatar image
cleaver answered ·

No! the wires are not big enough. And the 50A breaker panel will be required. 50A contains 2 legs of 120v. 30A system contains 1 leg.

Why do you think you need a 50 amp for assist to work. I have it running on a 30 amp service.

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hintzcm avatar image
hintzcm answered ·

I have 10/3 running from shore power through my surge protector and into my inverter. 6/3 is running from the inverter back to the AC panel. Switching the breaker is recommended by Nate from Explorist Life (https://www.explorist.life/30a-camper-inverter-with-solar-and-alternator-charging-wiring-diagram/#Wiring_the_InverterCharger_AC_Distribution_Panel). I'd like Victron to confirm that, but I haven't found a way to contact them directly.

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jw1971 avatar image jw1971 commented ·

Yea, Nate does like to recommend that setup.


In the RV world 120/30A and 230/50A are the two common setups.

120V/50A is not very common. There is no official 3 prong 50A connector; so you usually see the 4 prong 230/50A used with one leg just not connected.

But when adding a Multiplus with power assist you can move up to 120/50A pretty easily and depending on your loads can be a nice upgrade.


The challenge is:

1) You need to move to 6/3 to handle the 50A versus 10/3 for the 30A. Sounds like you have that covered on your 50A run from inverter to panel.

2) You need a 50A single pole breaker. They do exist; but usually not easy to find. You can get them in the correct type off Amazon for your panel. Likely a HOMD from the picture. A dual pole 50A is for a 2-phase (230V) setup.

3) And here is the big one that makes this possible...the panel manufacture sells a 230/50A version which is 100% identical except with a dual pole input breaker and the 2nd leg bus bars installed. So with this knowledge we know the bus bars are ok for 50A so therefore what you are proposing to do is fine. They just don't offer a 120/50A as it's not a used configuration as pointed out above.


But not all panels will be downrated like this one is and this is one area Nate should spend some time explaining. I shudder that people are putting 50A breakers into a 30A limit panel and risking fires due to it.





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hjohnson avatar image
hjohnson answered ·

It would only be safe if a) your panel is rated for 50A and b) the wiring between your Multiplus and the Panel is also rated for 50A (aka 6AWG). In the case of my boat, I didn't want to run such crazy oversized wire, but still wanted to use the power assist feature (for when I'm on a 15A feed or some such) so I put a 32A breaker immediately adjacent to the inverter/charger to protect the wiring, then just ran 10AWG to my distribution panel.

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