Combiner box with split positive and common negative to MPP LV5048

[Jack2of3]

HI All,
I've looked in the MPP manual and didn't see any "don't do this".
I will have two PV Strings going to a MNPV6 with a split Positive bus bar with separate breakers for each string. The negative is not split so I am thinking they can be run in common (bonded) in the MNPV6.
I will then have the split positives and two "bonded" negative lines running to two MPPT on a single LV5048.

The question is: Can the negatives be "bonded" at the MNPV6 or should they be split also?

Thanks.

 

[Zil]

What do you mean by "bonded"? Try reading the MNPV6 manual. It details the connections from the panels. https://www.solar-electric.com/lib/wind-sun/MNPV3-6-Instructions.pdf

 

[MJSullivan]

HI All,
I've looked in the MPP manual and didn't see any "don't do this".
I will have two PV Strings going to a MNPV6 with a split Positive bus bar with separate breakers for each string. The negative is not split so I am thinking they can be run in common (bonded) in the MNPV6.
I will then have the split positives and two "bonded" negative lines running to two MPPT on a single LV5048.

The question is: Can the negatives be "bonded" at the MNPV6 or should they be split also?

Thanks.

So it appears you are not actually combining strings - correct?

 

[Jack2of3]

So it appears you are not actually combining strings - correct?

Correct. There will be two separate strings. Each going to one MPPT in the LV5048. The MNPV6 says the negatives can be bonded (AC term for neutral and ground on the same bus) in common for certain MPPT that have the circuitry but do not mention if the LV5048 is one of the models with the circuitry that has this capability. If no one knows definitively I'll add another negative bus and run them separately from the PV panel strings to the MNPV6.

 

[Jack2of3]

What do you mean by "bonded"? Try reading the MNPV6 manual. It details the connections from the panels. https://www.solar-electric.com/lib/wind-sun/MNPV3-6-Instructions.pdf

It does not cover if the LV5048 has the necessary circuitry to handle the Bonded/common negative bus thus the specific LV5048 question.

 

[Jack2of3]

I broke down and called MPP Solar support.
They strongly recommend separate negative bus bars to ensure the MPPT are isolated.