Steve Merrick
Member
- Location
- Anchorage, AK
I have a few questions regarding the use of flexible cords on a mobile industrial trailer. We are operating a waste treatment facility where we have 15 or 20 acres of contaminated soil under cover awaiting cleanup. A small mobile trailer is used as a changing room and staging area for each day's work. The trailer is equipped with a 480/208Y-120V transformer and distribution panel supplying a heater, lights and receptacles. The trailer is fed from the main building by a 480V flexible STOOW cable connected to any of a number of 480V welding receptacles located around the building. The trailer is moved to wherever the work is being performed that day, and is rarely in one place longer than a couple of months. The need for the cord to be better protected was recently spotlighted when the snow-covered cord was run over by a snow-blower and entangled in its impeller. Fortunately, only the ground wire of the 480V cord was damaged in the event.
First of all, I believe that the trailer should be classified as ?utilization equipment? which would allow it to be supplied by a flexible cord under 400.7(A)(6). Our Industrial Safety Group disagrees and believes that the trailer should be classified as a building, but they differ as to whether its power supply should be classified as a temporary or permanent installation. If classed as a permanent building, the trailer power supply would have to be hard piped, which would be ridiculous, as it could no longer be moved to where it is needed. Am I wrong?
One final question: assuming that the trailer is classified as ?utilization equipment? under 400.7, the cord requires protection from damage. We would prefer to route the cord through a ramp-style cable protector. Does NEC 400.14 allow this as a means of protection?
I apologize for the length of this question.
Thanks,
Steve Merrick, PE
GForce Engineering
Idaho Falls, ID
First of all, I believe that the trailer should be classified as ?utilization equipment? which would allow it to be supplied by a flexible cord under 400.7(A)(6). Our Industrial Safety Group disagrees and believes that the trailer should be classified as a building, but they differ as to whether its power supply should be classified as a temporary or permanent installation. If classed as a permanent building, the trailer power supply would have to be hard piped, which would be ridiculous, as it could no longer be moved to where it is needed. Am I wrong?
One final question: assuming that the trailer is classified as ?utilization equipment? under 400.7, the cord requires protection from damage. We would prefer to route the cord through a ramp-style cable protector. Does NEC 400.14 allow this as a means of protection?
I apologize for the length of this question.
Thanks,
Steve Merrick, PE
GForce Engineering
Idaho Falls, ID
