200+ Electrical Supervisor Interview Questions and Answers

The fuse rating for a 22 kW motor depends on the starting current and the type of motor.

• The starting current of the motor should be considered when selecting the fuse rating.

• The type of motor (e.g. induction, synchronous) also affects the fuse rating.

• Consult the motor manufacturer's specifications or a qualified electrician for the appropriate fuse rating.

• A general rule of thumb is to use a fuse rating of 125% of the motor's full load current.

HT, LT, and DG transformers are used for power distribution. Load changeover is done by switching between transformers.

• HT transformers are used for high voltage distribution, while LT transformers are used for low voltage distribution.

• DG transformers are used as backup power sources in case of power outages.

• Load changeover is done by switching between transformers based on the power demand.

• Proper safety measures must be taken while performing load changeover.

• Load changeover c...read more

PAC stands for Precision Air Conditioning, HVAC stands for Heating, Ventilation, and Air Conditioning, and AHU stands for Air Handling Unit.

• PAC is used in server rooms to maintain a constant temperature and humidity level to protect sensitive equipment.

• HVAC is used to control the temperature, humidity, and air quality in buildings.

• AHU is a device used to circulate and regulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.

• PAC temperature is typical...read more

CTs and PTs are devices used in electrical systems to measure current and voltage respectively.

• Current Transformers (CTs) are used to measure current in electrical circuits by stepping down the current to a safe level for measurement.

• Potential Transformers (PTs) are used to measure voltage in electrical circuits by stepping down the voltage to a safe level for measurement.

• CTs and PTs are commonly used in power distribution systems to provide accurate measurements for protecti...read more

Yes, a 3-phase line voltage can be converted to single-phase, but it requires specific methods and considerations.

• Using a transformer, you can step down the 3-phase voltage to a single-phase voltage.

• Phase conversion can be achieved using a rotary phase converter.

• In some cases, you can use two phases of a 3-phase supply to create a single-phase supply.

• Example: A 3-phase motor can be run on single-phase power using a phase converter.

An Air Circuit Breaker (ACB) is a type of circuit breaker that operates by using air as the medium to extinguish the arc formed when the circuit is interrupted.

• ACB is designed to protect electrical circuits from overloads and short circuits.

• When a fault occurs, the ACB trips and interrupts the flow of current by separating the contacts.

• The arc formed during interruption is extinguished by the blast of compressed air.

• ACBs are commonly used in industrial applications due to the...read more

I have experience in repairing electrical hand drill machines, focusing on troubleshooting and maintenance.

• Conducted routine maintenance on hand drill machines to ensure optimal performance.

• Diagnosed electrical issues in machines, leading to timely repairs and reduced downtime.

• Replaced faulty components, such as switches and motors, to restore functionality.

• Implemented safety protocols during repairs to prevent accidents and ensure compliance.

I see the layout of the building and plan the conduiting accordingly.

• I look for the location of the electrical room and the main distribution panel.

• I identify the areas where electrical outlets and switches will be needed.

• I plan the conduiting route based on the layout of the building and the electrical requirements.

• I consider any obstacles such as beams or columns that may affect the conduiting.

• I ensure that the conduiting is installed in compliance with local electrical cod...read more

The question is unclear and lacks proper grammar.

• The question seems to be asking about changing the VFD mother and TBM machine oil and the number of motors involved.

• However, the question is poorly phrased and lacks clarity.

• It is difficult to provide a specific answer without more information or clarification.

Star-delta and DOL starters have distinct wiring configurations for controlling motor operations efficiently.

• DOL Starter: Directly connects the motor to the power supply, providing full voltage.

• Star-Delta Starter: Initially connects the motor in star configuration to reduce voltage, then switches to delta for full power.

• DOL is simpler and used for smaller motors (up to 5 HP).

• Star-Delta is preferred for larger motors (above 5 HP) to reduce starting current.

• Control wiring for D...read more

The ten delta test is a diagnostic test used to assess the condition of power transformers.

• The ten delta test measures the change in power factor between the initial and final stages of a transformer's life.

• It is used to detect insulation deterioration and moisture content in the transformer oil.

• Equipment used for the ten delta test includes a power factor test set, a transformer turns ratio tester, and a megohmmeter.

Current in a motor can be found using an ammeter.

• Connect the ammeter in series with the motor

• Turn on the motor and measure the current

• Current can be found using the formula I = V/R

• Use a clamp meter to measure current without breaking the circuit

VCBs use vacuum as the arc quenching medium while ACBs use air. VCBs are more reliable and require less maintenance.

• VCBs use vacuum as the arc quenching medium, while ACBs use air

• VCBs are more reliable and require less maintenance compared to ACBs

• VCBs have higher breaking capacity than ACBs

• VCBs are more suitable for medium voltage applications, while ACBs are commonly used in low voltage applications

An Electrical Supervisor oversees electrical systems, ensuring safety, compliance, and efficient operation in various projects.

• Knowledge of electrical codes and standards (e.g., NEC, IEC) is crucial for compliance.

• Experience with troubleshooting electrical systems, such as identifying faults in wiring or equipment.

• Familiarity with safety protocols, including lockout/tagout procedures to prevent accidents.

• Ability to read and interpret electrical schematics and blueprints for e...read more

Electrical panels can be used by various types of contractors.

• Electrical contractors are the most common type of contractors who use electrical panels.

• General contractors may also use electrical panels for specific projects.

• HVAC contractors may require electrical panels for their heating and cooling systems.

• Plumbing contractors may need electrical panels for water heaters or pumps.

• Fire protection contractors may use electrical panels for fire alarm systems.

• Security system con...read more

We are delivering electrical products and equipment for various industries and applications.

• Our products include transformers, switchgear, motors, and control panels.

• We provide electrical solutions for industries such as manufacturing, construction, and energy.

• Our equipment is responsible for powering machinery, lighting, and other electrical systems.

• We ensure that all our products meet safety standards and are installed correctly.

• Examples of our work include installing elect...read more

The process of fixing modular box in Mivan sheet for wall conduiting in RCC involves several steps.

• First, mark the position of the box on the Mivan sheet.

• Then, drill a hole in the Mivan sheet at the marked position.

• Insert the modular box into the hole and secure it with screws.

• Connect the conduits to the modular box and run them through the RCC wall.

• Finally, seal the gap between the modular box and the Mivan sheet with sealant.

• Ensure that the box is level and flush with the M...read more

Single phase and three phase are two types of electrical power distribution systems.

• Single phase has one live conductor and one neutral conductor, while three phase has three live conductors and one neutral conductor.

• Single phase is commonly used in residential applications, while three phase is used in industrial and commercial applications.

• Single phase systems provide a lower power capacity compared to three phase systems.

• Three phase systems are more efficient and provide a...read more

Star delta starter is used to reduce starting current and torque in induction motors.

• Reduces starting current and torque in induction motors

• Protects motor windings from damage

• Increases motor lifespan

• Used for high power motors

• Commonly used in industries such as oil and gas, mining, and manufacturing

The question is unclear and does not make sense.

• The question is grammatically incorrect and lacks clarity.

• It is difficult to understand what the interviewer is asking.

• There is no clear context or topic mentioned in the question.

• It is not possible to provide a descriptive answer based on the given question.

Transformer safety parts include fuses, circuit breakers, and grounding systems.

• Fuses protect against overcurrent and short circuits.

• Circuit breakers protect against overloads and faults.

• Grounding systems prevent electrical shock and protect equipment.

• Other safety parts may include temperature sensors and pressure relief devices.

Yes, I have experience in handling all types of LV HV panel fixing and substation cable joining works.

• I have worked on various types of LV HV panels and substation cable joining projects.

• I am familiar with the safety protocols and procedures involved in such works.

• I have experience in troubleshooting and resolving issues related to panel fixing and cable joining.

• I have worked with different types of cables and connectors.

• I am well-versed in reading and interpreting electrical...read more

Lightning protection is provided in cable tray to prevent damage to electrical equipment and ensure safety.

• Lightning protection in cable tray helps divert lightning strikes away from the cables and equipment.

• It reduces the risk of electrical surges and voltage spikes caused by lightning.

• By providing a path of least resistance, it helps dissipate the electrical energy from lightning strikes.

• It protects the cables, preventing them from melting or catching fire due to high curre...read more

Maintenance types include preventive, corrective, predictive, and condition-based, each with specific safety protocols.

• Preventive Maintenance: Regularly scheduled tasks to prevent equipment failure, e.g., routine inspections and part replacements.

• Corrective Maintenance: Repairs made after equipment failure, ensuring safety protocols like lockout/tagout are followed during repairs.

• Predictive Maintenance: Uses data analysis tools to predict equipment failures, requiring safety ...read more

A transformer is an electrical device that transfers electrical energy between circuits through electromagnetic induction.

• Types of transformers include: Step-up, Step-down, Isolation, and Auto-transformers.

• Step-up transformers increase voltage while decreasing current, e.g., used in power plants.

• Step-down transformers decrease voltage while increasing current, e.g., used in residential power supply.

• Isolation transformers provide electrical isolation between circuits, enhancin...read more

Assessing motor health involves monitoring parameters like vibration, temperature, and current to ensure optimal performance.

• Vibration analysis: Excessive vibration can indicate misalignment or bearing issues. Typical values are below 0.1 in/sec.

• Temperature monitoring: Motors should operate below 80°C. Higher temperatures can signal overload or insulation failure.

• Current draw: Compare actual current to rated current. A significant increase may indicate mechanical issues or ov...read more

Troubleshooting is the systematic process of diagnosing and resolving issues in electrical systems.

• Identify the problem: Gather information about the issue, such as symptoms and error messages.

• Analyze the system: Review schematics and documentation to understand the system's design and operation.

• Test components: Use tools like multimeters to check the functionality of individual components.

• Isolate the fault: Narrow down the potential causes by testing different sections of th...read more