Codes for conveyor applications

I am designing a conveyor application that requires 24VDC @ 20A, I plan on using 12AWG wire for my dc power along the side frame with a metal cover over the side frame and will not run past 30'. I want to tap off of the 12AWG wire into different devices, which have onboard fusing, by using insolation displacements taps. The power supply is fused internally on the output side, which protects my circuit from overcurrent. With my design, are there any violations with codes, the only thing I was able to find was in Art.720-4. By using the sideframe with a cover, does that qualify it as a trough? Keep in mind that there are holes punched in the side frame for rollers and supports, but the cover will not have any holes. Any help would be appreciated.