Danem Engineering Works Electrical Technician Interview Questions and Answers

A power cable is an electrical cable used for transmitting electrical power.

• Power cables are used to connect electrical equipment to a power source.

• They are typically made of copper or aluminum conductors surrounded by insulation and protective sheathing.

• Power cables come in various sizes and types, such as single-core, multi-core, armored, or non-armored.

• Examples of power cables include extension cords, overhead power...read more

Control cable is a type of electrical cable used to transmit control signals in industrial automation applications.

• Control cable is typically made up of multiple conductors, each with its own insulation.

• It is commonly used to connect sensors, switches, and other control devices to programmable logic controllers (PLCs) or other control systems.

• Control cable is often shielded to protect against electromagnetic interferen...read more

The diagram that shows how lights work is called an electrical wiring diagram.

• Electrical wiring diagram shows the connections between electrical components and how they are wired together.

• It includes symbols for switches, lights, and other electrical devices.

• It helps electricians understand how the electrical system works and troubleshoot problems.

• For example, a wiring diagram can show how a light switch controls a lig...read more

MCC panel stands for Motor Control Center panel.

• It is an assembly of one or more enclosed sections having a common power bus and principally containing motor control units.

• It is used to control and distribute power to electric motors.

• It is commonly used in industrial and commercial settings.

• It can be customized to meet specific needs of the facility or application.

• Examples of MCC panel manufacturers include Siemens, Sc

A power panel is an electrical distribution board that receives power from a main source and distributes it to various circuits.

• It is also known as a distribution board or breaker panel

• It contains circuit breakers or fuses to protect the circuits from overloading

• It can be found in residential, commercial, and industrial buildings

• Examples include the main breaker panel in a house or the electrical room in a factory

A two-way switch is installed by connecting the wires to the appropriate terminals on the switch.

• Identify the two-way switch and its terminals

• Connect the live wire to the common terminal

• Connect the two switch wires to the two remaining terminals

• Ensure all connections are secure and insulated

• Test the switch to ensure it is working properly

XLPE cable is a type of electrical cable with cross-linked polyethylene insulation.

• XLPE stands for cross-linked polyethylene.

• XLPE cable has better electrical and mechanical properties than PVC cable.

• XLPE cable is commonly used in power distribution and transmission systems.

• XLPE cable can handle higher temperatures than PVC cable.

• XLPE cable is more expensive than PVC cable.

Cat 5&6 cables are used for high-speed data transmission in networking applications.

• Cat 5&6 cables have higher bandwidth capabilities than older cables like Cat 3.

• They can support faster data transfer rates and are less susceptible to interference.

• Cat 5&6 cables are commonly used in Ethernet networks, VoIP systems, and video surveillance systems.

• They are also used for home networking and internet connections.

• Cat 6 cabl...read more

Substations use various equipment for power distribution and control.

• Transformers: Step up or step down voltage levels.

• Circuit breakers: Protect the system from overloads and faults.

• Switchgear: Control and isolate electrical circuits.

• Busbars: Distribute power to different parts of the substation.

• Relays: Monitor and protect the system from abnormalities.

• Capacitors: Improve power factor and voltage stability.

• Disconnect s...read more

CTs, PTs, LAs, and Transformers are electrical devices used in power systems for measurement, protection, and voltage transformation.

• CTs (Current Transformers) are used to measure and transform high currents into manageable levels for instruments and relays.

• PTs (Potential Transformers) are used to measure and transform high voltages into low voltages for instruments and relays.

• LAs (Lightning Arresters) are used to prot...read more

Circuit breakers are safety devices that protect electrical circuits from damage caused by overload, short circuit, or ground fault.

• Circuit breakers are used to prevent damage to electrical equipment and wiring.

• They interrupt the flow of electricity when there is an overload, short circuit, or ground fault.

• Circuit breakers are commonly used in homes, businesses, and industrial settings.

• They come in different sizes and ...read more

The rating of copper and aluminium cables depends on their size, insulation, and intended use.

• Copper cables have higher conductivity and are therefore rated higher than aluminium cables of the same size.

• The rating of a cable also depends on its insulation material and thickness.

• Cables used for high voltage transmission have higher ratings than those used for low voltage applications.

• For example, a 10 AWG copper cable m...read more

Types of protection on Transformer side line side

• Overcurrent protection

• Differential protection

• Restricted earth fault protection

• Overvoltage protection

• Under voltage protection

Different types of relays are used for protection system such as overcurrent, differential, distance, and directional relays.

• Overcurrent relays are used to protect against overloads and short circuits.

• Differential relays are used to protect transformers and generators from internal faults.

• Distance relays are used to protect transmission lines from faults.

• Directional relays are used to protect against faults in specific...read more