Main Power Terminal Blocks?

[K.Porter]

I've been laying out some diagrams for the electrical on this year's robot, and the only components that I haven't been familiar with are the new terminal blocks.

These are the modular square boxes that are intended to be attached to a supplied rail.
On FIRST's supplied diagram, they are wired between the main breaker/switch and all of the breaker panels and components. I've never used terminal strips like this, I've just wired directly from the positive output on the main switch to the positive input on the component boards, and then used a separate terminal block to return on the negatives to.

So really, my question is, does anyone know if these terminal blocks have to be wired to the positive side of the circuit out of the main breaker?

Thanks.
-Kevin