On a sunny, warm, humid summer afternoon in the Northeast, the owner of a self-loading log truck was loading tree trimmings from a power line maintenance operation. The operator was performing the trimming operation as a contractor for an electric power company.
The operator was in his mid-50s and had over 20 years’ experience in logging and trucking, as well as in working around power lines in similar situations. He was a licensed arborist.
Unsafe Act or Condition:
The truck was parked perpendicular to and facing the road with the front of the truck cab extending under the power line. The loader operator’s seat was not directly under the line, but the operator was very close to the phone line, which was below the power line.
While reaching for a bucket of wood, the loader boom came close enough to the power line to allow an electric arc to energize the loader. The arc jumped several feet, according to witnesses. Humid weather conditions contributed to this incident.
The operator was electrocuted immediately and slumped over in the loader seat. He was declared dead at the scene. Power was knocked out in the nearby area.
Position landings well away from energized power lines, such that no part of the loader or logs being loaded can come within 100 feet of an energized line.
For other logging equipment, OSHA has published a table establishing minimum allowable distances between equipment and power lines, relating allowable minimums to known voltages. If it is not possible or practical to determine voltage, it is advisable to treat all power lines as being at the highest voltage and taking the maximum precaution, which is to maintain a 50-foot distance.
Before beginning equipment operations near power lines, determine if any part of the equipment, load line, or load, if operated up to the equipment’s maximum working radius in the work zone, could get closer than 50 feet. If it should be necessary to operate closer than that, arrange with the utility owner/operator to de-energize and visibly ground the power line at the work site.
Source: Forest Resources Association