MNDC125 & MNDC175 disconnect breaker stud size

[nlt999]

Hi!
I can't find info on the MS website, so asking here:  I need to know the size (diameter) of the terminal studs on the back of the factory-installed disconnect breakers in the MNDC125 and MNDC 175 disconnect boxes.  Also would like the size of the terminal bolts in the standard shunt if possible.  Installing on an island and everything has to be on-hand before starting the installation, so need to know what size connectors to put on the inverter and battery cables inside this box.

Thanks for your help!  Nick

[Vic]

Hi Nick,

At the link for the 125 A breaker,  says 1/4 Studs -- believe that this means 1/4" studs:
http://www.midnitesolar.com/productPhoto.php?product_ID=251&productCatName=Breakers&productCat_ID=16&sortOrder=20&act=p

The 175 and 250 A breakers say, "3/8 Studs":
http://www.midnitesolar.com/productPhoto.php?product_ID=578&productCatName=Breakers&productCat_ID=16&sortOrder=3&act=p

For the Deltec Shunt,  the bolts for the battery leads are 3/8-16:
http://www.solar-electric.com/batteries-meters-accessories/metersmonitors/mkb-500-50.html

Could not find the bolts speced for the MNSHUNT,  but those bolts almost have to be 3/8-16 also,  due to the current rating -- 500A -- and this is really has been the standard for decades.

I have no personal experience with these e-panels.

FWIW.    Vic

[nlt999]

Thanks Vic!

My bad for not digging hard enough.... didn't think of looking for the breaker itself, but should have.

Big help!

Nick

[Vic]

Hi Nick,

You are welcome.
Have fun with the installation.    Vic

[new2PV]

Is the  MNDC125A breaker non polarized? I want it to work as a protection device between 2 strings.  This is not a large frame breaker as the 175 and 250, so I was just wondering if it is safe it use it as this purpose.

[Vic]

Hi new2..,

There is,  IMO,  no reason to believe that the MNDC125 is not polarity sensitive,  that is,  I do believe that this breaker IS polarity sensitive.

This breaker appears to be 1" wide --  E-frame:
http://www.midnitesolar.com/pdfs/EA1-X0-17-708-22A-ZB.pdf

Believe that Schneider uses E-Frame breakers in their DC Conduit boxes for PV into the CC,  and as the output breaker on CCs.

Yes the MNDC 175 and MNDC 250 are wider,  1.5",   and are referred to as F-Frame,  IIRC.

We use a lot of E-Frame breakers here,  but do believe that they ARE polarity sensitive,  polarized,  and similar terms,  to the best of my knowledge.

Robin,  and several other MN folks would know for certain.

It has been stated on this Forum,  that the MNEDC breakers in ratings of 5 to 100 Amps are NOT polarity sensitive.

FWIW,  Good Luck,   Vic

[vtmaps]

Midnite's panel mount breakers are not polarized.  The din-rail breakers are polarized.

--vtMaps

[new2PV]

That is great to know, next question how can i find a enclosure to mount 2 of these breakers and have room for 3 sets of 4/0 cables. I want to use 1 breaker for each parallel string of batteries.  Also it be outdoors, but covered from rain, and I would need a bus that could hold 250 amps attached to the load side.

[new2PV]

I am going with fuses,  no one makes an enclosure to fit these breakers, in 3R.

[Vic]

I am going with fuses,  no one makes an enclosure to fit these breakers, in 3R.

Given your situation,  this seems to the best approach.  Good Luck,   Vic

[sledder]

Hi There
i have the mini disconnect and was wondering can the 125 amp mndc breaker be additionally mounted for the charge controller out disconnect.  I am getting the classic 150 controller.  I have a 175 amp breaker mounted currently in this panel as the invertor disconnect.
Also the incoming pv strings (two) requires two breakers.  what would you suggest as the best breaker?   din rail ?  panel mount ? i see the panel mount are not polarized but the din rail are.  looking for some guidance for the best selection.  if the 125 amp mndc cannot be additionally mounted, would the 100 amp MNEDC breaker work, suggest din rail or panel mount with this breaker as well ?  if panel mount what do i need to mount the breakers in the mini disconnect panel ?   
Thanks in advance for your help......

D

[Vic]

Hi sledder,  Welcome to the Forum,

I have never used any of the MidNite Mini DC panels.

It appears that NONE of these Mini DC panels  have space for two large DC breakers.

And,  IMO,  there is really no need to use a 125 Amp breaker for the Classic's output cable,   to the battery.   Even if you are using a cable that could safely carry 125 Amps of current,  sizing the breaker for 125 amps would not be required,  as,  in normal operation,  the Classic cannot deliver that much current.  As long as the Classic's output cable is sized large enough for the maximum amount of current that the Classic is rated to deliver,  plus a safety factor,   and the circuit breaker is sized to protect that cable from overheating,  then things should be fine,  as you probably know.

The Mini DC Manuals that I have looked at seem to be able to accept up to six DIN Rail breakers.   There is a reference to there being an adapter panel for the MNEDC breakers (Panel Mount),  but the manuals that I just looked at,   do not show anything other than DIN rail breakers.   If you need two breakers for PV inputs to the Classic (CC),  and you wanted the DIN 100 A breaker for the CC output,  then that would consume four breaker positions,  as the 80 and 100 A Din breakers use two positions on a panel.

If your Mini DC has an adaptor for Panel Mount breakers,  then this is probably a good approach,  as  it might possibly save you a bit of money,   verses using the double wide 80 or 100 A  DIN breakers ...   we do not know the details of your system.

Just some guesses from someone who has not ever used one of these Mini DC panels.   FWIW,   Vic