Outdoor Control Enclosure Minimum Height

[graczka]

I am working with a solar company. We are installing 17,000 heliostats in the solar field. On each heliostat, there is a NEMA 4X enclosure with various control equipment that power a pair of 480 VAC motors.
My question is about the minimum height. Currently, the drawings show the enclosure about 12" above grade. This would be very difficult to service at this height. Is there a code that mandates the minimum height of an outdoor control enclosure such as this?

 

[Dennis Alwon]

I don't believe you will find a minimum height.

 

[Jraef]

I've never seen a code reference to that, but your concern is something I wish more people thought about. I just had to commission a 600HP soft starter and the manufacturer put the controls and keypad/display at about 18" off the ground. I had to lay down on the floor to program the damed thing. When I complained, they said it was because the factory where it was made uses an elevated roller conveyor as the products move through the assembly line. So for the factory worker it was at chest height... BFD as far as I was concerned, they had no regard for the poor guys in the field who have to work on it.

But if you need some other reason to point to other than the installer's and service person's convenience, certainly if there is even a small a chance of flood, 12" above grade would pose a damage risk. I've used that argument before. Arguably though, the places where they put solar farms tend to be places where flooding is not generally an issue. Still might be worth looking into though. Where its it at?

 

[petersonra]

I have had to put stuff that low before. Didn't want to but it just ended up that was where it would fit.

I don't take any credit for it, but I did a project a long while back where the spec required a terminal strip for field devices to be run horizontally across the bottom of a control panel mounted on the floor. One of the field electricians called me personally to thank me for it. They had to lay on the ground and work over the edge of a 6" lip to wire the TS that was maybe 8 inches off the floor on the panel that was 2 feet away from the door.

I eventually asked the guy who wrote the spec why he did it that way. He said so it would be easier to wire the field devices as they came up through the floor. As you might guess, they actually came in through the top of the cabinet.