ELECTRICAL SAFETY, PULLEY
CALCULATIONS, AND NFPA 70E
STANDARDS. EXAM QUESTIONS AND
ANSWERS 100% PASS.
What is the Driving Pulley? - ANS The pulley attached to the motor shaft, which drives the
system.
What is the Driven Pulley? - ANS The second pulley that is turned by the Driving Pulley.
How is the speed of the Driven Pulley determined? - ANS It is determined by the speed of the
Driving Pulley and the diameters of both pulleys.
What is the formula to calculate the speed of the Driven Pulley? - ANS S' = (D x S) / d', where
D is the diameter of the Driving Pulley, S is the speed of the Driving Pulley, and d' is the
diameter of the Driven Pulley.
What does 'De-energized' mean in electrical safety? - ANS Free from any electrical
connection to a source of potential difference and from electrical charge.
What is an Arc-Flash Hazard? - ANS A source of possible injury or damage to health
associated with the possible release of energy caused by an electric arc.
2026 STUDY MATERIAL @COPYRIGHT RESERVED 1
, What is the purpose of establishing an Electrically Safe Work Condition? - ANS To ensure that
electrical conductors or circuit parts are disconnected from energized parts and verified to be
safe for work.
What does 'Incident Energy' refer to? - ANS The amount of thermal energy impressed on a
surface during an electrical arc event, expressed in calories per square centimeter.
What is the role of a Qualified Person in electrical safety? - ANS One who has demonstrated
skills and knowledge related to electrical equipment and has received safety training to identify
and avoid hazards.
What is the significance of the Working Distance in electrical safety? - ANS It is the distance
between a person's face and chest area and a prospective arc source, affecting the incident
energy experienced.
What is Lockout/Tagout? - ANS Specific practices and procedures to safeguard employees
from unexpected energization or startup of machinery during service or maintenance.
What does NFPA 70E require when multiple employers work together? - ANS They must
coordinate their safety procedures, especially within the limited approach boundary of exposed
energized electrical conductors.
What is an Electrical Hazard? - ANS A dangerous condition where contact or equipment
failure can result in electrical shock, arc-flash burn, thermal burn, or arc-blast injury.
What is the formula to determine the diameter of the Driven Pulley? - ANS d' = (D x S) / S',
where D is the diameter of the Driving Pulley, S is the speed of the Driving Pulley, and S' is the
speed of the Driven Pulley.
What is the formula to determine the diameter of the Driving Pulley? - ANS D = (d' x S') / S,
where d' is the diameter of the Driven Pulley, S' is the speed of the Driven Pulley, and S is the
speed of the Driving Pulley.
2026 STUDY MATERIAL @COPYRIGHT RESERVED 2
CALCULATIONS, AND NFPA 70E
STANDARDS. EXAM QUESTIONS AND
ANSWERS 100% PASS.
What is the Driving Pulley? - ANS The pulley attached to the motor shaft, which drives the
system.
What is the Driven Pulley? - ANS The second pulley that is turned by the Driving Pulley.
How is the speed of the Driven Pulley determined? - ANS It is determined by the speed of the
Driving Pulley and the diameters of both pulleys.
What is the formula to calculate the speed of the Driven Pulley? - ANS S' = (D x S) / d', where
D is the diameter of the Driving Pulley, S is the speed of the Driving Pulley, and d' is the
diameter of the Driven Pulley.
What does 'De-energized' mean in electrical safety? - ANS Free from any electrical
connection to a source of potential difference and from electrical charge.
What is an Arc-Flash Hazard? - ANS A source of possible injury or damage to health
associated with the possible release of energy caused by an electric arc.
2026 STUDY MATERIAL @COPYRIGHT RESERVED 1
, What is the purpose of establishing an Electrically Safe Work Condition? - ANS To ensure that
electrical conductors or circuit parts are disconnected from energized parts and verified to be
safe for work.
What does 'Incident Energy' refer to? - ANS The amount of thermal energy impressed on a
surface during an electrical arc event, expressed in calories per square centimeter.
What is the role of a Qualified Person in electrical safety? - ANS One who has demonstrated
skills and knowledge related to electrical equipment and has received safety training to identify
and avoid hazards.
What is the significance of the Working Distance in electrical safety? - ANS It is the distance
between a person's face and chest area and a prospective arc source, affecting the incident
energy experienced.
What is Lockout/Tagout? - ANS Specific practices and procedures to safeguard employees
from unexpected energization or startup of machinery during service or maintenance.
What does NFPA 70E require when multiple employers work together? - ANS They must
coordinate their safety procedures, especially within the limited approach boundary of exposed
energized electrical conductors.
What is an Electrical Hazard? - ANS A dangerous condition where contact or equipment
failure can result in electrical shock, arc-flash burn, thermal burn, or arc-blast injury.
What is the formula to determine the diameter of the Driven Pulley? - ANS d' = (D x S) / S',
where D is the diameter of the Driving Pulley, S is the speed of the Driving Pulley, and S' is the
speed of the Driven Pulley.
What is the formula to determine the diameter of the Driving Pulley? - ANS D = (d' x S') / S,
where d' is the diameter of the Driven Pulley, S' is the speed of the Driven Pulley, and S is the
speed of the Driving Pulley.
2026 STUDY MATERIAL @COPYRIGHT RESERVED 2
