Electrically Driven or Controlled Irrigation Machines

Article 675 addresses irrigation machines, most famously the center pivot, a quarter-mile of pipe on wheels with drive motors at each tower and control wiring running the length of the span. It defines how to size the supply for the collective motor load, how the traveling and collector-ring connections are made, and how the whole metal structure gets bonded so a fault cannot leave it energized.

This is agricultural work with a serious shock angle, because the machine is wet, grounded to the earth it rolls on, and touched by workers. I make the equipment grounding conductor continuous through every tower and bond the structure thoroughly, so if a conductor chafes through, the breaker clears it instead of a farmhand finding the fault.

When it applies

Article 675 covers electrically driven irrigation machines, the big center-pivot and linear systems that crawl across a field. You have a traveling power connection feeding a long metal span, multiple drive motors spaced along it, and all of it standing in a wet, grounded field. The rules focus on the moving supply, the motor circuits, and thoroughly bonding that large metal structure.

Common mistakes

• Weak or corroded bonding between spans, so part of the machine is not tied into the grounding system.
• Undersizing the supply for the combined pull of all the drive motors starting.
• Neglecting equipment grounding on a structure that people touch while standing in wet soil.

In the field

On a pivot I check the bonding across every span joint. It is a giant metal frame in a wet field, and if the bond between sections corrodes through, someone touching it can complete the circuit the ground is supposed to carry.