NCCCO Digger Derrick
Powerline Safety Practice
Exam Fall 2026| 250 Most
Tested Questions Collection &
Verified Detailed Answers
With Rationales| Tutor
Verified Success Exam) Graded
A+
Section 1 — Fundamental Powerline Safety
1. What is the primary electrical hazard when operating a digger
derrick near an overhead powerline?
A. Hydraulic overheating
B. Electrocution or electric shock
C. Excessive tire wear
D. Loss of engine power
Rationale: Contact or dangerous proximity to an energized powerline
can cause severe injury or death through electric shock or
electrocution.
,2. Unless the utility owner/operator confirms otherwise, how must
a powerline be treated?
A. Deenergized
B. Grounded
C. Insulated
D. Energized
Rationale: OSHA requires employers to presume that powerlines are
energized unless the utility owner/operator confirms that they have
been deenergized and visibly grounded at the worksite.
3. Which components must be considered when determining
whether a digger derrick could contact a powerline?
A. Only the boom
B. Only the load
C. Only the auger
D. Equipment, load line, load, rigging, and lifting accessories
Rationale: The powerline assessment must consider the entire
equipment/load system, not merely the boom.
4. Why can a load create a powerline hazard even when the boom
itself remains clear?
A. The load can become heavier
B. The load can damage the boom
C. The load or rigging may extend into the required clearance zone
D. The load automatically deenergizes the line
Rationale: Clearance applies to the equipment, load line, load,
rigging, and lifting accessories.
5. What is the safest assumption concerning an unidentified
overhead electrical conductor?
A. It is communication cable
B. It is insulated
,C. It is deenergized
D. Treat it as energized
Rationale: Treating an unknown line as energized prevents workers
from relying on an unsafe assumption.
6. What should an operator do if the powerline voltage is
unknown?
A. Assume it is less than 50 kV
B. Use the shortest clearance distance
C. Obtain voltage information from the utility owner/operator
D. Continue if a spotter is present
Rationale: Accurate voltage information is necessary when using
Table A clearance distances.
7. Who should normally provide requested powerline voltage
information?
A. The equipment dealer
B. The crane operator
C. The signal person
D. The utility owner/operator
Rationale: OSHA §1926.1407(e) addresses voltage information
provided by the utility owner/operator.
8. Under OSHA's rule, how quickly must the utility owner/operator
provide requested voltage information when Option 3 is used?
A. Within 1 hour
B. Within 24 hours
C. Within two working days
D. Within two weeks
Rationale: Section 1926.1407(e) specifies two working days for
requested voltage information.
9. What is the purpose of a pre-job powerline assessment?
, A. To determine fuel consumption
B. To calculate tire pressure
C. To identify electrical hazards and establish appropriate controls
D. To select the operator's seat
Rationale: Planning before operations helps prevent equipment or
loads from entering hazardous clearance zones.
10. What should be considered when identifying the work zone?
A. Only the operator's immediate view
B. Only the current boom position
C. The area in which the equipment will be operated
D. Only the parking area
Rationale: OSHA requires the work zone to be identified before
equipment operations begin.
Section 2 — OSHA Table A Clearance
11. Under OSHA Table A, what is the minimum clearance for a
powerline up to 50 kV?
A. 5 ft
B. 10 ft
C. 15 ft
D. 20 ft
Rationale: Table A specifies 10 feet for voltages up to 50 kV.
12. What is the minimum Table A clearance for a line over 50 kV
through 200 kV?
A. 10 ft
B. 15 ft
C. 20 ft
D. 25 ft
Powerline Safety Practice
Exam Fall 2026| 250 Most
Tested Questions Collection &
Verified Detailed Answers
With Rationales| Tutor
Verified Success Exam) Graded
A+
Section 1 — Fundamental Powerline Safety
1. What is the primary electrical hazard when operating a digger
derrick near an overhead powerline?
A. Hydraulic overheating
B. Electrocution or electric shock
C. Excessive tire wear
D. Loss of engine power
Rationale: Contact or dangerous proximity to an energized powerline
can cause severe injury or death through electric shock or
electrocution.
,2. Unless the utility owner/operator confirms otherwise, how must
a powerline be treated?
A. Deenergized
B. Grounded
C. Insulated
D. Energized
Rationale: OSHA requires employers to presume that powerlines are
energized unless the utility owner/operator confirms that they have
been deenergized and visibly grounded at the worksite.
3. Which components must be considered when determining
whether a digger derrick could contact a powerline?
A. Only the boom
B. Only the load
C. Only the auger
D. Equipment, load line, load, rigging, and lifting accessories
Rationale: The powerline assessment must consider the entire
equipment/load system, not merely the boom.
4. Why can a load create a powerline hazard even when the boom
itself remains clear?
A. The load can become heavier
B. The load can damage the boom
C. The load or rigging may extend into the required clearance zone
D. The load automatically deenergizes the line
Rationale: Clearance applies to the equipment, load line, load,
rigging, and lifting accessories.
5. What is the safest assumption concerning an unidentified
overhead electrical conductor?
A. It is communication cable
B. It is insulated
,C. It is deenergized
D. Treat it as energized
Rationale: Treating an unknown line as energized prevents workers
from relying on an unsafe assumption.
6. What should an operator do if the powerline voltage is
unknown?
A. Assume it is less than 50 kV
B. Use the shortest clearance distance
C. Obtain voltage information from the utility owner/operator
D. Continue if a spotter is present
Rationale: Accurate voltage information is necessary when using
Table A clearance distances.
7. Who should normally provide requested powerline voltage
information?
A. The equipment dealer
B. The crane operator
C. The signal person
D. The utility owner/operator
Rationale: OSHA §1926.1407(e) addresses voltage information
provided by the utility owner/operator.
8. Under OSHA's rule, how quickly must the utility owner/operator
provide requested voltage information when Option 3 is used?
A. Within 1 hour
B. Within 24 hours
C. Within two working days
D. Within two weeks
Rationale: Section 1926.1407(e) specifies two working days for
requested voltage information.
9. What is the purpose of a pre-job powerline assessment?
, A. To determine fuel consumption
B. To calculate tire pressure
C. To identify electrical hazards and establish appropriate controls
D. To select the operator's seat
Rationale: Planning before operations helps prevent equipment or
loads from entering hazardous clearance zones.
10. What should be considered when identifying the work zone?
A. Only the operator's immediate view
B. Only the current boom position
C. The area in which the equipment will be operated
D. Only the parking area
Rationale: OSHA requires the work zone to be identified before
equipment operations begin.
Section 2 — OSHA Table A Clearance
11. Under OSHA Table A, what is the minimum clearance for a
powerline up to 50 kV?
A. 5 ft
B. 10 ft
C. 15 ft
D. 20 ft
Rationale: Table A specifies 10 feet for voltages up to 50 kV.
12. What is the minimum Table A clearance for a line over 50 kV
through 200 kV?
A. 10 ft
B. 15 ft
C. 20 ft
D. 25 ft
