GFI Breaker MNDC-GFP63 as a PV input disconnect

[Riley]

Hi Folks - I need to install a PV disconnect switch/breaker indoors at the input to my Charge Controller (my 'expert' solar installer didn't put one in). There are rooftop breakers in the combiner box but I need one at my charge controller.

I am planning to use the Midnite Bigbaby box with a 150VDC breaker (6 AWG cabling). I see that GFI is now NEC code and seems like a good idea. Can I use the MNDC-GFP63 GFI 'breaker' to act as my disconnect switch OR should I buy a separate 60A DV breaker. I guess I have room to do both in the box if needed and maybe that's what I should do given the midnite diagrams they show both a breaker and a GFI used in series.

What I really need to do is to be able to disconnect the PV panels when I am shutting down my system. Right now I can't disconnect the PV panels when disabling the Charge Controller.

[Vic]

Hi Riley,  welcome to the Forum,

I forget,  are you using Schneider CCs,  Classics,  ...   or   ...

In either case,  I believe that Schneider CCs,  and know that the Classics have built-in GFP.  IIRC,  Schneider uses a FUSE,  and the Classics use a PTC resistor (this is a temperature-controlled resistor,  than is self-ressetting).

Believe that you were considering using a HV CC.  Have a look at the NEW MidNite Hawke's Bay,  and Barcelona CCs,  these are very slick,  and quite feature-rich !!

Perhaps my memory is failing about your system,  ans possible plans.

FWIW,  Vic

[Riley]

Hi Vic   
Thanks for the nice welcome and also the good memory. I thought I had my profile setup here but guess not. I was thinking of going high voltage but "the boss" talked me down to a smaller small system upgrade with more panels and my PV shutoff that's needed.

Job one is to get an indoor PV shutoff figured out. Then add panels but stay with my 150V system (Conext 60-150). I did checked the MPPT and it doesn't need the PV- disconnected.
If I end up upgrading the charge controller, I can change out the breakers at that time.

And next stop is to go read up on the Hawks Bay threads...

Also in my plans for upgrade is 50% more panels, hopefully that gets me further into the shoulder seasons.

After posting the above question, I checked the price of a 60A/150VDC breaker and it's super cheap. So
I guess my real question is, what's the difference (from an over-current protection standpoint) between a GFI breaker and just a plain breaker. Oerhaps the GFI doesn't really provide over current protection after-all?

I will wire one in. 

 

[ClassicCrazy]

If you just wanted a small box to hold some breakers you could also use a midnite combiner box to do that . You don't have to tie the breakers all together and can wire them separately .

Larry