OSHA Accident Investigation · Summary #14482020
ELECTRICAL,REVERSE POLARITY,CORD SET,ELECTROCUTED,ATTACHMENT PLUG,E C,GROUND FAULT,EQUIPMENT GROUNDING,ELECTRIC DRILL
Event description
ELECTRIC SHOCK - UNGROUNDED ELECTRIC DRILL
Investigation abstract
A CARPENTER WAS DRILLING A HOLE IN A METAL DOOR CASING TO MOUNT 4-INCH METAL HIN THIS CORD SET WAS PLUGGED INTO A PERMANENT, 120-VOLT, 20-AMPERE RECEPTACLE. THE MOLDED ATTACHMENT PLUG ON THE EXTENSION CORD SET HAD ITS GROUNDING PRONG REMOVE D. IN DARKNESS, THE CARPENTER INSERTED THE ATTACHMENT PLUG INTO THE PERMANENT RE CEPTACLE IN A REVERSE POLARITY POSITION. THIS CAUSED THE UNGROUNDED CIRCUIT COND UCTOR TO BE CONNECTED TO THE GROUNDED POLE OF A STANDARD SINGLE-PHASE, THREE-WIR E CIRCUIT. A GROUND FAULT PERMITTED THE ELECTRIC DRILL CASE TO BECOME PART OF TH E CIRCUIT THROUGH THE IDENTIFIED GROUNDED CONDUCTOR (WHICH WAS CONNECTED TO THE UNGROUNDED CONDUCTOR AT THE POINT OF REVERSE POLARITY). THERE WAS NO EQUIPMENT G ROUNDING CONDUCTOR TO PROVIDE A PATH TO GROUND. WHEN THE EMPLOYEE, WHO WAS HOLDI NG THE DRILL, GRABBED THE METAL STAIR RAILING, HIS BODY COMPLETED THE ELECTRIC C GES. HE WAS USING A 3/8-INCH-DRIVE, METAL-CASE ELECTRIC DRILL. THE EMPLOYEE WAS IRCUIT TO GROUND. THE EMPLOYEE COLLAPSED; THE ENERGIZED DRILL LANDED ON HIS CHES T; AND HE WAS ELECTROCUTED. STANDING IN A DOORWAY, WITH HIS LEFT FOOT ON A CONCRETE SURFACE AND HIS RIGHT FO OT ON A METAL-GRATE STAIRWAY LANDING. THE EMPLOYEE WAS LEFT HANDED. IT IS BELIEV ED THAT HE HELD THE ELECTRIC DRILL IN HIS LEFT HAND AND HELD THE METAL STAIR RAI LING (TO THE RIGHT OF THE DOOR) WITH HIS RIGHT HAND. THE ELECTRIC DRILL HAD A 3- CONDUCTOR, 6-FOOT FLEXIBLE CORD BETWEEN THE GROUNDING-TYPE ATTACHMENT PLUG AND T HE DRILL. THE DRILL WAS CONNECTED TO A 3-CONDUCTOR TEMPORARY LIGHTING CIRCUIT, W HICH IN TURN WAS ENERGIZED BY A STANDARD 3-CONDUCTOR, ROUND, EXTENSION CORD SET.
Victim
-
#1 Fatality Age 48 M
- Nature of injury
- 10
- Part of body
- 4
- Event type
- 12
- Source
- 15
- Occupation code
- 567
- Human factor
- 12
- Environmental factor
- 18
- Task assigned
- 1
Codes shown verbatim from OSHA's accident-investigation database. A human-readable decoder is coming in a future release once the accident_lookup2 dictionary is loaded.