Victron Multiplus II, 16A shore and Power Assist fusing dilema

[pmar]

Hi All I need your advise on fusing AC part of my instalation. I want to install new charger-inverter (Victron Multiplus 12/3000/120-32), my boat have 16A shore connection, and my AC appliences are fused with 16A RCBO and 16A b-class MCB's.
Thing is that Victron have function called "Power Assist" which according to manual can add in peaks up to 13A taking it from my battery bank. Quote from manual:

With its PowerAssist feature the MultiPlus-II can add up to 3 kVA (that is 3000 / 230 = 13 A) to the output during periods of peak power requirement. Together with a maximum input current of 32 A this means that the output can supply up to 32 + 13 = 45 A." The AC input must be protected by a fuse or magnetic circuit breaker rated at 32 A (for 3 kVA model) "

So taking into account that my input power is 16a, my fuse on AC input (shore power conected to Multiplus) must be dual pole 16A MCB thats obvious. (it will not draw more than 16A). But i have two questions:
1. Do I need RCBO before Inverter? - manual says nothing about it.
2. Should I change all fusing on AC panel to 32A (16A shore +up to 13A Power Assist =29A) - It seems scary from perspective that 95% of time it will be up to 16A consumption.

[smac999]

you could (you would likly have to change all the wire as well). or you could just disable the assit funtion so it doesn't blow the output breakers. it depends how much power you need on the boat.

the charger will still reduce power as you add load. IE if you turn on 14a of stuff on the boat, the charger will claw back and only use 2a so it doesn't blow the breaker. then when the load turns off it will kick up the charger again. so that funtion is still really usefull. the assit is only if you need more then 16a of loads excluding the charger.

[BAD ORCA]

Also, on the Multiplus, there is an option to limit the amount of current the inverter/charger can draw from shore power. Its even possible to do this remotely with the optional control panel. It doesnt answer your question, but an option to limit current if you think it will help. It seems like a popular feature with RV'rs who sometimes plug into 15A shore power. They dial down what the inverter/charger can draw to avoid popping a breaker.

I have not used this feature yet so cant offer any helpful details though.

[pmar]

Thanks!I think I will just disable that function, for now I've never managed to pop any of my MCBs so I think it's ok not to use Power assist, regarding limiting input current, yes, this will be set to 16A.

[hjohnson]

Originally Posted by pmar

Thanks!I think I will just disable that function, for now I've never managed to pop any of my MCBs so I think it's ok not to use Power assist, regarding limiting input current, yes, this will be set to 16A.

I’d encourage you not to do this, as the power assist function is really handy.

We normally have 30A shore power, but often visit our friends’ dock where we can plug into a dodgy 15A outlet.

What we do is just dial back the power limit on our multiplus (12/2000/120 in our case) to 10A and go on with our lives. No matter what we do on the AC side of the equation, we don’t draw any more than 10A from our friends.

Let’s say our battery is half discharged, our hot water tank (750W) wants to turn on, and I need to use the 1500W heat gun to do some repair work. I just do it, and don’t have to worry about it.

In my system, I have a 30A double pole breaker on my power outlet, and another 30A double pole breaker immediately after the multiplus, as it could conceivably source 45A, but I didn’t want to run 6awg cabling.

Anyhow, if I was you, I’d build your electrical system for a full 30A service, then use the multiplus to limit your boat’s draw to 15A or even 13A or so.

[ejs]

The current rating is determined from the wiring, not from the source. If your wiring is sized for 15 amps, the breakers need to be 15 amps.

[hjohnson]

Originally Posted by ejs

The current rating is determined from the wiring, not from the source. If your wiring is sized for 15 amps, the breakers need to be 15 amps.

Sure, but the 20' of 10AWG triplex to ensure the run from the shorepower inlet to the multiplus and back to the breaker panel is rated for 30A is pretty cheap.

I honestly haven't seen a shorepower inlet that was rated for 15A, the smallest you usually see is 30A.

That's not to say that we don't plug the boat into 20A, or 15A circuits, especially if we're visiting a marina that charges less for lower current sockets, but we just use the multiplus to limit our current draw so that we don't trip shoreside/pedistal breakers.

[smac999]

Originally Posted by hjohnson

I honestly haven't seen a shorepower inlet that was rated for 15A, the smallest you usually see is 30A

.

A 16a shore inlet is 230v. Which is the same power as your 30a 120v cord. Which doesn’t need assisting on a small boat. There is a world outside of North America.

[hjohnson]

Originally Posted by smac999

A 16a shore inlet is 230v. Which is the same power as your 30a 120v cord. Which doesn’t need assisting on a small boat. There is a world outside of North America.

First, I’m not in the USA.

Secondly, if you go back and read their initial posting, they’re talking about a Victron Multiplus 12/3000/120-32 which is a 120v unit, not 230v. 16A 120v is really weird for a boat,