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alaskannoob avatar image
alaskannoob asked

How to wire 240V generator cable into Multiplus II 48/8000?

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My Honda 7000 generator has a 240V output. The plug has two hots, a neutral and a ground so I assume I would make a cable with four wires. But how would I wire this into the AC-IN of the Multiplus II 48/8000 which seems to have a single L, an N, and a ground bar?

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3 Answers
Alexandra avatar image
Alexandra answered ·

@AlaskanNoob

You would wire your two in parallel up to an incoming breaker. You need equal lengths for good current sharing to each unit.

Then wire the generator into the breaker as the source. Or if you also have grid then into a change over switch.

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alaskannoob avatar image alaskannoob commented ·

We are off grid. Are you saying we'd wire the generator into the breaker box and not to the MP2 directly?

And at the breaker box the two legs would go one each to an MP2's AC-IN?

So the Breaker Box would take the four wires from the generator (two hots, neutral, and ground) and then output that into one hot, a ground, and a neutral for AC-IN to MPIIA, as well as one hot, one ground, and one neutral to the AC-IN to MPIIB?

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sharpener avatar image
sharpener answered ·

I don't know the generator in question but it sounds like the output is 120-0-120V so if the Multis are 230V input (you don't say despite the request above) then connect the two lives to the L and N of both Multis and leave the neutral disconnected but insulated.

As you are off grid the N side of the Multis should be bonded to their earth terminals, not sure if that is achieved by the internal bonding relays in yourEd circumstances, @Alexandra will know! And to the genny earth and to an earth electrode in the ground.

Edit: in this thread it is explained that the internal bonding relay is closed only if there is no power on the AC-In. So in your case you need to do it externally.

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alaskannoob avatar image alaskannoob commented ·
Okay, connecting a generator is far more complicated than I thought it was going to be!


Thanks for that info, I'll try to digest it.

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sharpener avatar image
sharpener answered ·

It is not that complicated but it would help us to help you if you answer @Alexandra's question "So what model inverters do you have exactly? "

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alaskannoob avatar image alaskannoob commented ·

@sharpener, we have two Multiplus II 48/8000s. But we learned recently that they cannot operate in parallel as the dealer had told us. So we are now in the process of trying to determine what inverter(s) to get to replace them.


If we were to get a single Multiplus II 48/15000 inverter, if I am understanding your response, we could wire the two hots of the generator cable to the L and N of the AC-IN on the Multiplus, leave the neutral disconnected but insulated (and I assume not put a terminal on that wire), and I assume we would also hook the ground wire into the ground bar of the Multiplus?

Thanks for trying to help me out, sorry for my ignorance and the delay. It has been a hectic few days.

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sharpener avatar image sharpener alaskannoob commented ·
Yes I see you have had big issues with the parallel 8kWs but a single 15kW will solve yr problems. I believe the above will work fine assuming the new Multi will take 230 - 240V between L and N - which I presume to be the case as you were talking about using an autotransformer on the output to get 120V. Good luck!
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alaskannoob avatar image alaskannoob sharpener commented ·

@sharpener and @Alexandra,

We settled on replacing the two MP II with a single 48/15000 Quattro.

The Quattro takes generator input with 187-265VAC, 45-65Hz, Power Factor 1.

Our Honda 7000 puts out two legs of 120V as discussed above. So, just to confirm, if I wire the Honda with one hot going into the AC1 L and the other hot going into the AC1 N, then the ground connected, and then the neutral wire not connected, that should work?

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sharpener avatar image sharpener alaskannoob commented ·
Yes I believe so.
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keaton85 avatar image keaton85 alaskannoob commented ·
How are you not able to run them in parallel?
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alaskannoob avatar image alaskannoob keaton85 commented ·
The Multiplus II 48/8-15K units do not operate in parallel as I recently learned. It's in the data sheet and the manual is being updated to reflect that information as well.
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