Inspection Detail

Inspection: 303082564 - Nabors Drilling Usa Inc, Gulf Coast Division

Inspection Information - Office: Baton Rouge Area Office

Investigation Summary

An oil well drilling company had been on a site for about 52 days, drilling an oil well. They were going to drill to a depth of approximately 3700 meters and were at a depth of 3123 meters. The employees would work 7 days on and 7 days off. The evening and early morning temperatures at the well site were near 0 degrees Celsius. A derrick operator had been on the site for only 5 days, though the company had employed him previously. The employee asked his supervisor if he could put the Dayton space heater at the site in the changing room because it was extremely cold in the room during the evening and early morning. The changing room was located in the front of a grounded metal structure that had a tool room in the rear. A metal wall separated the two rooms. A metal bench was located in the center of the changing room and metal lockers were attached to the walls. The structure was located next to the site power plant near the base of the drilling rig. The employer had the heater's power supply cord coiled and resting on the platform between the tool room and the power plant with a plastic bag over the attachment plug. To connect the heater to a receptacle outlet, the employee ran the cord through an opening near the ceiling of the changing room and through the tool room to the power plant. The employee plugged the heater into a 240-volt outlet, turned it on, and found it to be working. The metal-framed heater was resting on the metal bench in the center of the changing room, and the bench was welded to the metal floor. When the employee lifted the heater off the bench to hang it on the wall, he was electrocuted. An investigation found that the opening through which the employee ran the cord was too small to accommodate the heavy-duty, 240-volt, three-wire with ground, four-pin attachment plug on the heater's power supply cord. It was believed that the employee had removed the plug, passed the cord through the hole, and reinstalled the plug. (The employer's policy required any electrical work to be performed by an electrician.) The equipment grounding conductor had been connected to the pin for a circuit conductor, and the resulting ground fault had energized the frame of the heater. The wiring inside the heater had deteriorated, but that had not contributed to the accident.

Keywords: E GI V, REPAIR, ELECTRICAL, ELECTROCUTED, ATTACHMENT PLUG, GROUND FAULT, EQUIPMENT GROUNDING, UNTRAINED