ONTARIO ELECTRICIAN LICENSING EXAM
QUESTIONS AND CORRECT ANSWERS
1. Which of the following is the primary purpose of grounding in
electrical systems?
A. To reduce electricity costs
B. To provide a safe path for fault currents
C. To increase voltage levels
D. To regulate current flow
Grounding protects people and equipment by providing a safe path for
fault currents to earth.
2. According to the Ontario Electrical Safety Code (OESC), how often
must inspections of electrical installations be conducted?
A. Every 3 years
B. Every 5 years
C. As required when changes or new installations occur
D. Annually
Inspections are required whenever new installations or significant
changes are made, rather than on a fixed schedule.
3. Which conductor color is typically used for the neutral wire in
residential wiring in Canada?
A. Black
B. Red
C. Blue
D. White
The neutral conductor is generally white or natural grey, as per
Canadian electrical standards.
4. What is the maximum allowable voltage drop for branch circuits
supplying sensitive electronic equipment?
, A. 3%
B. 5%
C. 2%
D. 10%
Voltage drop should be minimized for sensitive equipment, generally not
exceeding 2%.
5. Which device is designed to protect people from electric shock due
to leakage currents?
A. Circuit breaker
B. Residual Current Device (RCD) / Ground Fault
Circuit Interrupter (GFCI)
C. Fuse
D. Contactor
RCDs detect leakage currents to ground and disconnect power to prevent
shock.
6. When installing aluminum wiring, what precaution must be taken?
A. No special precautions
B. Use anti-oxidant compound and properly rated connectors
C. Only use fuses
D. Only for lighting circuits
Aluminum can oxidize and expand, so connectors rated for aluminum and
anti-oxidant compounds are required.
7. What is the main purpose of a circuit breaker?
A. To reduce power consumption
B. To store electrical energy
C. To protect wiring and equipment from overcurrent
D. To increase voltage
Circuit breakers prevent damage from excessive current by interrupting
the flow when it exceeds a set value.
8. In a three-phase system, what is the phase-to-phase voltage if the phase-
, to-neutral voltage is 120 V?
A. 120 V
B. 150 V
C. 200 V
D. 208 V
Phase-to-phase voltage in a balanced three-phase system is √3 times the
phase-to-neutral voltage: 120 × 1.732 ≈ 208 V.
9. What type of conductor is most commonly used for residential
branch circuits in Ontario?
A. Aluminum
B. Copper
C. Steel
D. Silver
Copper is preferred due to its high conductivity and durability.
10. According to the OESC, which of the following areas requires
GFCI protection?
A. Living room outlets
B. Bathrooms, kitchens, and outdoor outlets
C. Bedrooms
D. Hallways
Areas with water presence require GFCI protection to reduce shock
hazards.
11. What is the maximum length of flexible cord that can be
used for a portable appliance?
A. 5 meters
B. 15 meters
C. 25 meters
D. 50 meters
Flexible cords are limited to 15 meters for safe handling and to prevent
voltage drop and overheating.
QUESTIONS AND CORRECT ANSWERS
1. Which of the following is the primary purpose of grounding in
electrical systems?
A. To reduce electricity costs
B. To provide a safe path for fault currents
C. To increase voltage levels
D. To regulate current flow
Grounding protects people and equipment by providing a safe path for
fault currents to earth.
2. According to the Ontario Electrical Safety Code (OESC), how often
must inspections of electrical installations be conducted?
A. Every 3 years
B. Every 5 years
C. As required when changes or new installations occur
D. Annually
Inspections are required whenever new installations or significant
changes are made, rather than on a fixed schedule.
3. Which conductor color is typically used for the neutral wire in
residential wiring in Canada?
A. Black
B. Red
C. Blue
D. White
The neutral conductor is generally white or natural grey, as per
Canadian electrical standards.
4. What is the maximum allowable voltage drop for branch circuits
supplying sensitive electronic equipment?
, A. 3%
B. 5%
C. 2%
D. 10%
Voltage drop should be minimized for sensitive equipment, generally not
exceeding 2%.
5. Which device is designed to protect people from electric shock due
to leakage currents?
A. Circuit breaker
B. Residual Current Device (RCD) / Ground Fault
Circuit Interrupter (GFCI)
C. Fuse
D. Contactor
RCDs detect leakage currents to ground and disconnect power to prevent
shock.
6. When installing aluminum wiring, what precaution must be taken?
A. No special precautions
B. Use anti-oxidant compound and properly rated connectors
C. Only use fuses
D. Only for lighting circuits
Aluminum can oxidize and expand, so connectors rated for aluminum and
anti-oxidant compounds are required.
7. What is the main purpose of a circuit breaker?
A. To reduce power consumption
B. To store electrical energy
C. To protect wiring and equipment from overcurrent
D. To increase voltage
Circuit breakers prevent damage from excessive current by interrupting
the flow when it exceeds a set value.
8. In a three-phase system, what is the phase-to-phase voltage if the phase-
, to-neutral voltage is 120 V?
A. 120 V
B. 150 V
C. 200 V
D. 208 V
Phase-to-phase voltage in a balanced three-phase system is √3 times the
phase-to-neutral voltage: 120 × 1.732 ≈ 208 V.
9. What type of conductor is most commonly used for residential
branch circuits in Ontario?
A. Aluminum
B. Copper
C. Steel
D. Silver
Copper is preferred due to its high conductivity and durability.
10. According to the OESC, which of the following areas requires
GFCI protection?
A. Living room outlets
B. Bathrooms, kitchens, and outdoor outlets
C. Bedrooms
D. Hallways
Areas with water presence require GFCI protection to reduce shock
hazards.
11. What is the maximum length of flexible cord that can be
used for a portable appliance?
A. 5 meters
B. 15 meters
C. 25 meters
D. 50 meters
Flexible cords are limited to 15 meters for safe handling and to prevent
voltage drop and overheating.
