MPP LV6048 circuit breaker questions

[Jazzmonger]

I'm installing 2 of these in 180 degree/240v parallel configuration giving me 12kw total production, what is the maximum size of the circuit disconnect beaker I use on each output leg? 12kw= 100A at 120v and 50A at 240v. So 2 x 50A breakers, one on L1 and one on L2?

or do I put 25 A breakers on each L1 & L2 output on both inverters (total of 4). The parallel config is giving me heartburn.

I’m also confused as to why the bypass current breaker is only 40A, not 50A? Esp if these units are rated for 6kw each?

Jeff

 

[iamrich]

Not much help I am afraid, but I would run four 25a breakers. You just have to be super careful to match each line to the same bus. I think there is a thread someone on this topic.

 

[BentleyJ]

or do I put 25 A breakers on each L1 & L2 output on both inverters (total of 4).

Jeff

The 4 breaker approach as you stated gives you the most flexibility because you can turn off L1 & L2 on either individual inverter if it needs to be isolated for servicing while the other Inverter is still powering your loads.
Take a look at the Midnight Solar combiner boxes. They sell the breakers and the "finger" style combiner bus bars with mechanical lug.

 

[BentleyJ]

I'm installing 2 of these in 180 degree/240v parallel configuration giving me 12kw total production, what is the maximum size of the circuit disconnect beaker I use on each output leg? 12kw= 100A at 120v and 50A at 240v. So 2 x 50A breakers, one on L1 and one on L2?


I’m also confused as to why the bypass current breaker is only 40A, not 50A? Esp if these units are rated for 6kw each?

Jeff

1) I'm not an MPP Brand expert but have read through the literature fairly thoroughly. According to the MPP 6048 Manual this model is split phase capable with only 1 unit as it has L1, L2 & N lugs. When used in parallel, the amperage doubles but both inverters are still each individually outputting both 120 & 240V. I could be wrong, please feel free to let me know.

2) The 40A bypass breaker is sized to protect the internal transfer relay which is rated at 40A according to MPP specs. 6kW at 240V would imply a 2 pole, 25A breaker with a handle tie so the 40A is upsized quite a bit anyway.