Electrical Hazards and Utility Line Safety Flashcards

What is 'step potential' in the context of electrical hazards during tree work?

Answer: The voltage difference between two points on the ground that a worker's feet can span

Step potential is the voltage difference between two ground points separated by a step distance, which can drive current through a worker's body when a downed energized line contacts the ground.

When trimming trees near distribution lines, which condition requires an arborist to STOP work and notify the utility?

Answer: Discovering that a conductor's insulation is cut, abraded, or missing

Damaged or missing conductor insulation creates an immediate electrocution hazard; work must stop and the utility must be notified before any further operations.

A tree crew is asked to remove a tree whose trunk leans toward a 7,200-volt primary distribution line. What is the FIRST action?

Answer: Establish the minimum approach distance and assess whether the work can be done safely without contacting the line

Before any cutting begins, the crew must establish whether the minimum approach distance can be maintained; if it cannot, the utility must be contacted to de-energize or guard the line.

Which personal protective equipment is SPECIFICALLY required when an arborist must work within the electrical hazard zone of an energized line?

Answer: Rubber insulating gloves and sleeves rated for the voltage present

Rubber insulating gloves and sleeves rated to the line voltage are the required PPE when a qualified electrical worker must contact or come within the restricted approach boundary of an energized conductor.

Under ANSI Z133, what is the minimum approach distance for a qualified line-clearance arborist working near a 4,160-volt (phase-to-phase) distribution line?

Answer: 1 foot 0 inches (0.30 m)

ANSI Z133 Table A-1 specifies a minimum approach distance of 1 foot 0 inches for voltages up to 4,999 volts (phase-to-phase) for qualified line-clearance arborists.

What does the term 'qualified line-clearance arborist trainee' mean regarding electrical hazard work?

Answer: A worker in training who may only work within the minimum approach distance under the direct supervision of a qualified line-clearance arborist

ANSI Z133 defines a qualified line-clearance arborist trainee as someone who works inside the MAD only under direct supervision of a qualified line-clearance arborist.

A limb falls and drapes across a 12,000-volt primary line, but does not sever it. What is the CORRECT crew response?

Answer: Evacuate the area, establish a safety perimeter, and contact the utility to de-energize before any limb removal

A limb in contact with an energized primary conductor creates an extreme electrocution risk; only the utility can safely de-energize the line before removal attempts.