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Almot's avatar
Almot
Explorer III
Aug 04, 2014

Breakers box and bus bars, round 2

Still scratching my head how to install 2 short insulated bus bars from Midnite Solar into "Big Baby" enclosure from the same Midnite. You people warned me that this Baby isn't big enough for 2 bars, now I believe it.

Here how I thought to mount it: one bus bar next to Din breakers, another one - across.



The red bus is in manufacturer's suggested location. The black bus is where I hoped to fit it - doesn't look good, no room to put the wires in either black bus or Din breakers on the left end.

My choices:
A) Mount red Positive bus in the box, and put this fancy $12 insulated black Neg bus on the wall next to the box, and cover it with some yogurt cup. It's Neg anyway, not much danger of short. Dammit, could've bought $3 terminal in Home Depot, maybe even with cover.

B) Try and return Big Baby box with Din breakers to Az WindSun, lose half of the money between shipping cost and possible store fines, and order a 1" longer MNEDC box. Same width, 1" longer. Squeeze that black bus where I wanted. Still a bit cramped. Also, this longer box is for panel mount breakers, I'm not familiar with those but it seems that to do anything on them, you have to unscrew them all from the box cover. Din breakers look like easier to access.

I think - plan A?
  • Almot's avatar
    Almot
    Explorer III
    Westend - yes, Neg bus is a pass-through, can place it anywhere, can even eliminate it. I like your generous space, but I'm trying to fit controller, and breakers box, and leave a room for possible 2nd controller, - all in 12"-16" length of the wall because this is my only "dirty" closet.

    Greenrvgreen - this box is smaller than it looks. Any option with the 2nd bus on the left or on the right, would require a jeweler's skills.

    It's difficult to route the wires to the left bus directly through the left knock-out (or another drilled hole), the bus is too close to the left wall.
    It's difficult - with left Pos bus - to connect wires in that 3/4" crack between the left bus and left breakers. The terminals of Din breakers on the left are at the same level with the wire holes in the bus bar - same height from the box rear wall.
    The "lip" on the top won't let me work from above.

    Now visualize this box bolted to the FRONT wall of trailer crawl space accessible through the 14" high hatch from the SIDE trailer wall, so to do anything after it's been installed, I need to half-crawl in and turn to the side. It has to be not just a jeweler, but a yoga trainer with jeweler's skills :)
  • Option (C): Switch proposed locations of NEG and POS bars. POS on left with straight shot to left breakers and routing up and around to right breakers. NEG out of the way at the bottom.

    Option (D): POS on left (or bottom), NEG on right SIDE PANEL (if room available).

    Either way, considering how close everything's going to be, if there aren't knockout holes already perfectly placed I would drill and add strain relief nuts.
  • Assuming that this is for 12V solar installation and that the negative phase will basically be "pass through" with the red buss positive phase being protected by the breakers, I would locate the red buss in line with the breaker terminals and the black buss anywhere out of the way.

    I broke out the two phases into three 4" plastic buss boxes, two are positive phase and one is negative phase. A yogurt cup or Tupperware container will work as well.

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