Joinfworld Heavy Duty 500A Bus Bar Waterproof Power Distribution Block with 4*5/16"(M8)+2*3/8"(M10) Studs 48V DC Automotive Marine Battery Terminal Distribution Block with Cover - Negative&Positive

This is a well built busbar that I'm using on the load side of my battery cutoff in my solar install. It says that it is rated at 500A, but according to I = w x t x MF, where MF for CU is 1.2, I get 454A. Close enough for my install. One of the pictures shows 4x3/8" (M10) and 2x5/16" (M8). This is exactly backwards as the two center posts are M10 and the 4 outside ones are M8. The written description is correct. I like how close the posts are, tight, but they minimize distance to keep losses down and my lugs fit fine. The only downside is that mine came missing a few blanks and a few rubber grommets. I would suggest this is water "resistant" rather than water "proof". While the lid fits VERY snug, there isn't any gasket. The busbar is plated and believe this should work well for marine application - just don't submerge! For the money, it's a great value.

The build quality is surprisingly good. I didn't look for markings to see what kind of plastic it's made from, but it feels a lot like glass fiber reinforced nylon, the type of plastic quality power tools are made from. I expected it to be cheap and flimsy, but it's actually pretty rigid. The box ships with plastic knockouts that slide in and out and fit well enough that you can easily remove them, but they don't just fall out when you let go, so they're very convenient to work with. It also ships with grommets you can cut to suit your needs. I expected to get something that would work well enough and I'd just tuck it in a corner, but the quality is high enough that I'd be happy with it being displayed in a prominent location.

Quality product

I put this two busbar box on the tongue of my trailer. It was easier to use this than a couple of power posts because I had more than four cables to connect. The busbars themselves are good and thick. I'll never put anywhere close to the rated amps through it, but it's nice to know that it could handle it. I wouldn't call this box waterproof, but it will keep moisture off the cable lugs better than a power post. The first issue I had is that the holes for the fasteners that will hold the box to the trailer are too close to the corners. With a #8 screw, the nut is just barely touching the corner which meant that I couldn't get a socket on it and had to use an open end wrench to keep the nut from spinning. See the photo for a visual example. I would like to see the cable entry holes be just a bit larger in diameter. I had some larger cables (~2 awg) where the end of the cable lug came into contact with edge of the entry hole. As another reviewer said, it should come with rubber grommets for all 10 entry holes. I'm using 8 of the 10 holes but it came with only four grommets.

Worked out perfect for solar cables with low resistance and secure connection

excellent heavy duty bus bar at a reasonable price.

Great product quality, using it with 3x 280kwh batteries.

Works good and haven't gotten hot yet, though I did have to do some modification to use in my project, as some lugs are just to big (4/0 and fuses)

Solide et tres vient fait