Author Topic: single pole DC breakers.  (Read 1726 times)


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single pole DC breakers.
« on: December 15, 2019, 05:03:24 PM »
First question, What is the significance of the 63 amp breaker? Why is it the highest amp single pole breaker and why 63 amps. I had one in my solar - controller/controller - battery breaker box and one mid day, while a system was breaking up and my batteries were quite ready for a good charge  I watched cloud effect insolation take my potential 60 amp array pump over 70 amps into my batteries and pop the breaker.  I have remedied this with a Square D QOU 80 amp single pole breaker. This leads me to my next question....

 I'm curious why Midnite doesn't offer higher amperage 150 Vdc single pole breakers, seeing as the Classic charge controllers put out up to 96 amps.
12 Suntech 175's
   Classic 200
   Bogart Tri Metric
   Trace SW 4024 (brand new, sort of, first energized Feb. 2015)
  460 Ah. 24 volt LiFePo4  Battery bank


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Re: single pole DC breakers.
« Reply #1 on: December 15, 2019, 05:21:40 PM »
On the output side yes if you have 12v or 24v battery and have enough PV then you will want to install a 100 amp breaker .  It could be that the din rail type breakers can only take up to 6 gauge wire and that would be the max amps for that size wire.   Not sure what box you are using but I use Midnite MNDC boxes and it will fit either 5 MNEPV din rail breakers  or you can remove that mount for din rail and then use a supplied face plate that 3 MNEC panel mount breakers fit onto . The MNEC have 1/4 inch terminal studs so you can put ring terminals and larger gauge wire on them.    So for my 24v system I use the MNEC breakers 60 amp on the PV input and 100 amp on the output to battery. 

system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , Jakiper 48v LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batteries


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Re: single pole DC breakers.
« Reply #2 on: December 15, 2019, 05:30:26 PM »
Hello littleharbor2,

Am sure that you know of the MNEDC (Panel Mount)  breakers,   like this:

CBI makes the MNEPV DIN-Rail breakers for MidNite (and Outback).   Have not studied the CBI offerings,   but for a 150 VDC breaker,  perhaps that small physical size breaker cannot accommodate a higher current rating in a single breaker of that size,  or,  perhaps a somewhat larger terminal for a larger cable size.

It is good that you had the QOU in stock.

YES,   63 A seems to be a bit of a strange size,   but perhaps this is really the absolute  maximum continuous carry current that that package can handle.   There is probably another reason for this   ... perhaps some EU rating thing   ...   dunno.

FWIW,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!


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Re: single pole DC breakers.
« Reply #3 on: December 15, 2019, 11:02:39 PM »

I think it's that the  Midnite Solar MNEPV63 150VDC 63Amp Din Rail Mounted Breaker and smaller are mainly for PV input

The non-Din rail mount breakers are maybe what you wanted ?

Like the MNEDC 5A thru 100A panel mount breakers.

Hope this link works...

K7IQ 🌛  He/She/It


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Re: single pole DC breakers.
« Reply #4 on: December 20, 2019, 02:40:48 AM »
boB hit the nail on the head on this one.  You want to be using the panel mount breakers for the battery breaker.

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA