DC Negative and Grounding Question.

[SolarBro]

Im getting closer to finishing my lv5048 install and i have another bonding/grounding question.

Some say that the DC negative bus bar from my MNPV6 combiner box should be bonded with the ground bus bar.

The reason for is a path for the DC positive to find a path to DC negative to trip the breaker in the MNPV6 box. However im not sure about this.

Some also suggest bonding the ground and negative terminal on my battery bank. I have tesla modules and i dont like that idea of sending possible voltage to it if there is a ground fault somewhere.

Have you or how have you handled bonding the ground and DC negative on MPP solar arrangements?

Or is the DC negative and positive "floating" from the MNPV6 combiner to my mpp LV5048?

(All metal boxes and PV panels are grounded together and combined in the MNPV6 ground bus bar currently btw. I do not have a DC neg to Ground bond however)

 

[SolarBro]

Also since MPP solar doesnt have GFDI protection, what is the most practical way to set that up? Id like to know if any of my PV DC circuits have a ground fault.

 

[waktaylor]

I dont think the dc and ac need to interact at all.

The MPP LV2424 puts out "120" AC as 60 vac on each leg to ground instead of what you would be used to having which is 120 on the hot and "zero" on the neutral. Because of this I used 2 pole breakers in a sub panel box so each leg is protected.

No idea why you would tie the battery negative to anything but there are a few things I dont know.

 

[SolarBro]

Its not a very touched on subject. Im strictly speaking abou the DC side of things. GFDI protection and negative/ground bonding.

 

[iceledoar]

I would never connect my battery to earth ground. It would be like grounding your car. On the other side of the circuit I would not want any part of an AC circuit, bonded to the DC for a couple reasons.
1. Safety, any unprotected short on the AC circuit would apply 120vac to the -vdc side of the bus, at best it will smoke some.
2. Noise, both on the AC and DC circuits as the square and sin waves interact.

 

[SolarBro]

I would never connect my battery to earth ground. It would be like grounding your car. On the other side of the circuit I would not want any part of an AC circuit, bonded to the DC for a couple reasons.
1. Safety, any unprotected short on the AC circuit would apply 120vac to the -vdc side of the bus, at best it will smoke some.
2. Noise, both on the AC and DC circuits as the square and sin waves interact.

Its why im asking. Especially with GFDI since mpp solar doesnt have GFDI.

 

[SolarBro]

Anyone have knowledge about this GFDI breaker warning about the DC negative to Ground Bonding?