40+ Electrical Project Engineer Interview Questions and Answers

Important factors in cable calculation, types of communication used in automation industry, difference between analog input 4-20mA & analog input (0-10v), DG synch control panel & its working philosophy, various types of starter used in control panel, testing of panel as an individual at site, ingress protection.

• Cable calculation factors include voltage drop, current carrying capacity, and cable length.

• Types of communication used in automation industry include Ethernet, Modbu...read more

For a load less than 20 kW in a 3 phase Distribution board, a main incomer MCCB of 32A and a cable size of 6mm should be given.

• Main incomer MCCB size should be 32A for a load less than 20 kW in a 3 phase Distribution board

• Cable size should be 6mm for the Distribution board from the panel

The rating of ELCB in the swimming pool distribution board for underwater lights and swimming pool lights should be at least 30mA.

• The ELCB rating should be at least 30mA to provide protection against electric shock in wet conditions.

• This is important for safety in swimming pools where the risk of electric shock is higher.

• ELCBs with higher ratings such as 100mA or 300mA may not provide adequate protection in wet environments.

• It is recommended to consult with a qualified electr...read more

The wire size installed in the Distribution board for lighting circuits is typically 1.5mm² or 2.5mm².

• Typically, 1.5mm² or 2.5mm² wire sizes are installed in the Distribution board for lighting circuits.

• The wire size is chosen based on the current rating and load requirements of the lighting circuit.

• Proper wire sizing is crucial to ensure safety and prevent overheating in the electrical system.

The rating of ELCB and MCCB in a distribution board for power circuits should be based on the load requirements and safety regulations.

• ELCB rating should be based on the maximum fault current that can occur in the circuit to ensure proper protection against electrical shocks.

• MCCB rating should be selected based on the maximum current that the circuit can handle without tripping.

• Consider the type of load connected to the circuit (e.g. motors, lighting, heating) when determinin...read more

Traffic barrier system can be integrated with Fire Alarm System to provide early warning and evacuation signals in case of fire.

• Traffic barrier system can be equipped with fire alarm sensors to detect smoke or fire.

• Once fire is detected, the barrier system can automatically open to allow for evacuation of vehicles and people.

• The barrier system can also trigger alarms and flashing lights to alert nearby individuals of the fire.

• Integration with Fire Alarm System ensures quick r...read more

Site management involves overseeing the construction site and ensuring that the project is completed on time and within budget. Site issues refer to any problems that arise during the construction process.

• Site management involves coordinating with contractors, managing resources, and ensuring compliance with safety regulations.

• Site issues can include delays due to weather, unexpected construction challenges, or issues with permits and approvals.

• Effective site management and p...read more

Yes, a shunt trip is required for Smoke Extract Fan Panel.

• A shunt trip is required for Smoke Extract Fan Panel to ensure the fan can be shut off remotely in case of emergency.

• It is a safety feature that allows for quick deactivation of the fan in case of fire or smoke detection.

• Without a shunt trip, there may be delays in shutting off the fan during an emergency situation.

Yes, galvanised cable tray and cable trunking should be earthed for safety reasons.

• Galvanised cable tray and cable trunking should be earthed to prevent electric shock hazards.

• Earthing helps in dissipating any fault currents that may occur in the system.

• It also helps in protecting the equipment and personnel from potential electrical faults.

• Proper earthing ensures the system meets safety standards and regulations.

• Examples of earthing methods include connecting the tray or tru...read more

The interview question is about 1.33kv&11kv BOQ, power transformer description, and the role of CT/PT.

• BOQ for 1.33kv and 11kv involves preparing a bill of quantities for electrical equipment and materials required for the project.

• Power transformer description includes its specifications, such as voltage rating, power rating, winding configuration, cooling system, etc.

• CT/PT (Current Transformer/Potential Transformer) are used for measuring current and voltage respectively in h...read more

Answering questions related to electrical engineering

• To find if a transformer is star or delta connected, check the connection of the primary and secondary windings

• APL/BPL/AGL materials refer to Above Poverty Line/Below Poverty Line/Anti-Graffiti materials used in construction

• ROW stands for Right of Way, which is the legal right to pass through a property or land

The rating of the Main incomer ACB in the previous plant is typically determined based on the total load requirements of the plant.

• Main incomer ACB rating is usually determined based on the total load of the plant

• It is important to consider factors like peak load, future expansions, and safety margins when selecting the rating

• For example, if the total load of the previous plant was 5000kW, the Main incomer ACB rating might be 6300A

Precautions for installation of distribution and power transformers.

• Ensure proper grounding and earthing

• Ensure proper ventilation and cooling

• Ensure proper alignment and leveling

• Ensure proper cable and wire connections

• Ensure proper labeling and identification

• Ensure proper safety measures are taken during installation

• Ensure proper testing and commissioning before energizing

• Ensure proper maintenance and inspection after installation

A weigh feeder signal control diagram is a schematic representation of the control system for a weigh feeder.

• The diagram typically includes components such as sensors, transmitters, controllers, and actuators.

• It shows how the signals from the sensors are processed by the controller to adjust the flow of material in the weigh feeder.

• The control diagram may also include feedback loops to ensure accurate and consistent feeding.

• Example: Sensors measure the weight of material on t...read more

Transformers, switchgear, and cables are essential components of electrical systems.

• Transformers are used to step up or step down voltage levels in electrical systems.

• Switchgear is used to control and protect electrical equipment.

• Cables are used to transmit electrical power and signals.

• Types of transformers include power transformers, distribution transformers, and instrument transformers.

• Types of switchgear include circuit breakers, fuses, and disconnect switches.

• Types of ca...read more

Electrical flow from MV to LC involves transmission of high voltage electricity to low voltage loads.

• MV (medium voltage) refers to the distribution of electricity at a voltage level between 1 kV and 36 kV

• LV (low voltage) refers to the distribution of electricity at a voltage level below 1 kV

• Electrical flow involves the use of transformers to step down the voltage from MV to LV

• The flow of electricity is controlled and monitored through switchgear and protection devices

• Examples...read more

Electrical panels are enclosures that contain electrical components and are used to distribute power to various circuits.

• Electrical panels are also known as switchboards, distribution boards, or breaker panels.

• They are typically made of metal and have doors that can be opened to access the components inside.

• There are several types of electrical panels, including main breaker panels, subpanels, and load centers.

• Main breaker panels are the primary distribution point for electri...read more

Electrical drive uses electricity to power a machine while mechanical drive uses physical components like gears and belts.

• Electrical drive uses an electric motor to power a machine while mechanical drive uses physical components like gears and belts.

• Electrical drive is more efficient and requires less maintenance than mechanical drive.

• Examples of electrical drive include electric cars, elevators, and conveyor belts while examples of mechanical drive include bicycles, cars wit...read more

I have specialized in project management and electrical design.

• I have completed multiple successful projects within budget and on time.

• I have expertise in designing electrical systems for commercial and residential buildings.

• I have experience in managing teams and coordinating with clients and contractors.

• I continuously update my knowledge and skills to stay up-to-date with the latest technologies and trends.

• I have a strong focus on safety and quality assurance in all my proj...read more

A zero export device in a solar installation is a device that prevents excess solar energy from being exported back to the grid.

• A zero export device is typically used in situations where the grid cannot handle the additional power generated by the solar installation.

• It ensures that the solar energy is consumed locally or stored in batteries instead of being exported.

• Zero export devices can be programmed to limit the export of energy to a specific threshold.

• These devices are c...read more

WTG stands for Wind Turbine Generator. It generates power by converting wind energy into electrical energy.

• WTG consists of blades that capture wind energy and spin a rotor connected to a generator

• The generator converts mechanical energy from the rotor into electrical energy

• The electrical energy is then transmitted through power lines for distribution

• Examples of WTG include onshore and offshore wind farms

A control circuit diagram for a Direct-On-Line (DOL) starter with PLC involves connecting the PLC to control the operation of the DOL starter.

• The PLC is used to control the start and stop functions of the DOL starter.

• Input signals from sensors or switches are sent to the PLC for processing.

• The PLC then sends signals to the DOL starter to start or stop the motor.

• The control circuit diagram will show the connections between the PLC, sensors, switches, and DOL starter.

A transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction.

• Transformers are used to increase or decrease voltage levels in electrical circuits.

• There are two main types of transformers: step-up transformers and step-down transformers.

• Step-up transformers increase voltage levels, while step-down transformers decrease voltage levels.

• Examples of transformers include power transformers used in electrical substations an...read more

Electrical system work involves designing, installing, and maintaining electrical systems for buildings, machinery, and equipment.

• Designing electrical systems for buildings, machinery, and equipment

• Installing electrical systems and ensuring they meet safety standards

• Maintaining and repairing electrical systems to ensure they function properly

• Working with other engineers and professionals to ensure electrical systems integrate with other systems

• Examples include designing and i...read more

SFRA test is a diagnostic test performed on power transformers to assess their mechanical and electrical integrity.

• SFRA stands for Sweep Frequency Response Analysis.

• It is a non-intrusive test that measures the frequency response of a transformer to a swept sinusoidal input signal.

• The test helps in identifying mechanical and electrical faults in the transformer windings.

• SFRA test results can be compared with baseline measurements to detect changes or abnormalities.

• It is useful...read more

Types of conductors include copper, aluminum, and silver.

• Copper: most commonly used due to its high conductivity and corrosion resistance

• Aluminum: lighter and cheaper than copper, but not as conductive

• Silver: best conductor but expensive and not commonly used in electrical wiring

Transformer is a device that transfers electrical energy between two or more circuits through electromagnetic induction. Star delta connection is a method used to connect three-phase electrical motors. Electrical insulators are materials that resist the flow of electric current.

• Transformer: device that transfers electrical energy through electromagnetic induction

• Star delta connection: method for connecting three-phase electrical motors

• Electrical insulator: material that resis...read more

Transformers work on the principle of electromagnetic induction to transfer electrical energy from one circuit to another.

• Transformers have two coils of wire, a primary coil and a secondary coil, wrapped around a magnetic core.

• When an alternating current flows through the primary coil, it creates a magnetic field that induces a voltage in the secondary coil.

• The voltage induced in the secondary coil is proportional to the ratio of the number of turns in the secondary coil to t...read more

Power is the rate at which energy is transferred. Current is the flow of electric charge. Voltage is the electric potential difference.

• Power is measured in watts and is calculated by multiplying voltage and current.

• Current is measured in amperes and is the flow of electric charge through a conductor.

• Voltage is measured in volts and is the electric potential difference between two points in a circuit.

• Ohm's law relates power, current, and voltage: P = VI and V = IR.

• Power can be...read more

A motor is a device that converts electrical energy into mechanical energy, while a generator does the opposite.

• Motors use electrical energy to create rotational motion, while generators use rotational motion to create electrical energy.

• Motors are commonly used in appliances, vehicles, and industrial machinery, while generators are used in power plants and backup generators.

• Both motors and generators use electromagnetic principles to function.

• Motors and generators are often u...read more

A transformer is an electrical device that transfers electrical energy from one circuit to another through electromagnetic induction.

• Transformers are used to increase or decrease the voltage of an alternating current (AC) power supply.

• They work on the principle of electromagnetic induction, where a changing magnetic field induces a voltage in a coil of wire.

• Transformers consist of two coils of wire, called the primary and secondary coils, wrapped around a magnetic core.

• When a...read more

Quality process of work execution involves ensuring that all work is completed to a high standard and meets the required specifications.

• Establishing clear quality standards and procedures

• Regularly monitoring and reviewing work to ensure compliance with standards

• Providing training and support to staff to ensure they understand and can meet quality requirements

• Using quality control tools and techniques such as inspections, testing, and audits

• Addressing any issues or non-conform...read more

Digital signals are discrete, representing data as binary numbers, while analog signals are continuous, representing data as a continuous wave.

• Digital signals use discrete values (0s and 1s), while analog signals use continuous values.

• Digital signals are less prone to noise interference compared to analog signals.

• Examples of digital signals include computer data, while examples of analog signals include audio signals.

• Digital signals are easier to store and manipulate compared...read more

Single phase has one live wire and one neutral wire, while three phase has three live wires and one neutral wire.

• Single phase has a sinusoidal waveform, while three phase has three sinusoidal waveforms with a phase difference of 120 degrees.

• Single phase is commonly used in residential buildings for lighting and small appliances, while three phase is used in industrial applications for heavy machinery and equipment.

• Single phase systems have lower power capacity compared to thr...read more

Transformer works on the principle of electromagnetic induction to transfer electrical energy between two or more circuits.

• Transformers have two coils of wire, known as primary and secondary coils, which are wound around a core usually made of iron.

• When an alternating current flows through the primary coil, it creates a changing magnetic field around the coil.

• This changing magnetic field induces a voltage in the secondary coil, which results in the transfer of electrical ener...read more

Substation protection includes overcurrent, earth fault, differential, distance, and backup protection.

• Overcurrent protection is used to detect and isolate faults caused by excessive current flow.

• Earth fault protection is used to detect and isolate faults caused by current leakage to earth.

• Differential protection is used to detect and isolate faults between two parts of a system.

• Distance protection is used to detect and isolate faults based on the distance from the protection...read more

Switchgear protection is a system designed to protect electrical equipment from faults and abnormal conditions.

• Switchgear protection involves detecting faults and abnormal conditions in electrical equipment.

• It includes devices such as relays, circuit breakers, and fuses to isolate faulty equipment.

• The protection system ensures the safety of the electrical network and prevents damage to equipment.

• Examples of switchgear protection include overcurrent protection, earth fault pro...read more

The number of amps required for 1kVA depends on the voltage.

• The formula to calculate amps is: Amps = kVA / Voltage

• For example, if the voltage is 120V, then the amps required for 1kVA would be 8.33A

• If the voltage is 240V, then the amps required for 1kVA would be 4.17A

Load calculation is the process of determining the electrical load requirements for a project.

• Identify the electrical devices and equipment that will be used in the project

• Determine the power requirements (in watts) for each device

• Calculate the total power demand by summing up the power requirements of all devices

• Consider factors like diversity factor and demand factor to account for variations in usage

• Ensure that the electrical system can handle the calculated load without o...read more

Smart City Device configuration involves setting up various sensors, communication protocols, and data management systems to enable efficient city operations.

• Configure sensors for monitoring traffic flow, air quality, noise levels, etc.

• Implement communication protocols such as LoRaWAN, NB-IoT, or WiFi for data transmission.

• Set up data management systems like cloud platforms or edge computing for processing and analyzing collected data.

The selection of a contactor depends on the load type, voltage, current, and duty cycle.

• Consider the type of load (inductive, resistive, capacitive)

• Calculate the voltage and current ratings of the load

• Determine the duty cycle of the load (continuous, intermittent)

• Select a contactor with appropriate voltage, current, and duty cycle ratings

• Consider additional features like overload protection and coil voltage

Type 2 coordination chart is used in electrical engineering to show the coordination between protective devices.

• Type 2 coordination chart shows the coordination between protective devices in an electrical system.

• It helps in ensuring that the protective devices operate in the correct sequence during a fault.

• The chart typically includes time-current curves for different protective devices.

• It is important for preventing unnecessary tripping of protective devices and ensuring pro...read more