NEC 2017, top of pole arrays, disconnects, and sanity check

I'm very confused about current disconnect requirements for top of pole mount arrays and local inspector also is unfamiliar with solar installations because there has been so few in my area and he'd have to consult with someone else.

This installation is NOT feeding back to the grid.

Adding (Phase 1):
- Adding 20 Kyocera KC265 purchased from NAWS on 2 top-of-pole mounts.  Each mount will have 5 in series and 2 parallel strings.  Location 300-360ft from house entry.
- Adding 8 KD315GX purchased from NAWS on 1 top-of-pole mount.  4 in series and 2 parallel strings.  Location 600ft from house entry.
- Adding 3 Midnite Classic 250s, 1 for each array on top-of-pole mount.

Adding (Phase 2, move to 100% off-grid):
- Additional 20 KC265s with additional 2 Midnite Classic 250s on top-of-pole mounts.

Currently have (which was done 8-10 years ago):
- 48V battery bank
- Outback GVFX3648
- 1.2KW top-of-pole mount connected to MX60
- BOS components mounted on old Outback panel system with AC breakers on left and DC breakers on right.  So all equipment has circuit breakers where necessary when required by code when initially installed.

1) At each pole it appears I would need a MNPV6-250-Disco with the 300V circuit breakers.  This would allow 1 switch to disconnect that array.  How would this work if I had 8 arrays and a requirement to only have to throw 6 switches to disconnect power to a residence?

2) What disconnect would be required on outside of house?  Having 6 separate disconnect boxes seems excessive and expensive.

3) Are there requirements for disconnect inside before it connects to a DC breaker before the Midnite Classic?

4) Does having a battery based system require installation of Rapid Shutdown equipment such as the Midnite birdhouse to trigger the battery to be disconnected?

Thanks for any insight.  All these additional requirements are making it more and more confusing for a DIY'er to install a code-compliant system (if I'm not mistaken I believe the code even states now a "qualified" person must install the system :(  ).


  • VicVic Solar Expert Posts: 2,938 ✭✭✭✭
    edited October 2017 #2

    Hi Dave,

    You might want to poke around on the MidNite Forum.   Here is an older Thread there:

    You probably have looked on the MidNite Solar site:


    You might also ask your own questions there,   as well.

    FWIW,   Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • EstragonEstragon Registered Users Posts: 3,120 ✭✭✭✭✭
    You may also want to check with the local fire dept. to see if they can provide any advice.  In some localities, they're part of the approval process anyway, and the disco requirements may be driven by their concerns.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • DaveBDaveB Solar Expert Posts: 48 ✭✭✭
    Thanks for the replies.  Did more checking with inspectors and am told to use combinder/disconnect combo on array itself and a non-fused disconnect on the house for each array.
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