Interview Questions and Answers for Electrical Design Engineers
Top 10 Interview Questions for Electrical Design Engineers
Table of Contents
- 1. Circuit breakers, relays, and fuses
- 2. Software tools for electrical design
- 3. Cable sizing
- 4. Single-line diagrams
- 5. Medium-voltage switchgear design
- 6. Safety in electrical design
- 7. Earthing vs grounding
- 8. Challenging project experience
- 9. Short-circuit current calculation
- 10. Future career goals
1. Can you explain the difference between circuit breakers, relays, and fuses?
Sample Answer: A circuit breaker interrupts current during faults and can be reset. A fuse melts when overloaded and needs replacement. A relay controls high-power circuits using a low-power signal.
Tip: Be concise and use real-world examples from your projects.
2. What software tools do you use for electrical design?
Sample Answer: AutoCAD Electrical, ETAP, EPLAN, and MATLAB/Simulink for circuit design, simulations, and load flow studies.
Tip: Mention at least 2–3 industry-relevant tools.
3. How do you size a cable for a given electrical load?
Sample Answer: Consider current-carrying capacity, voltage drop, and short-circuit withstand capability. Follow IS/IEC standards and ensure cable rating exceeds peak demand.
4. Explain single-line diagrams (SLDs). Why are they important?
Sample Answer: An SLD represents the electrical system with single lines and symbols. It helps in understanding system configuration, power flow, fault analysis, and maintenance planning.
5. What are the key considerations in designing medium-voltage switchgear?
- Voltage and current ratings
- Short-circuit capacity
- Insulation type (air, SF6, vacuum)
- Safety features like interlocks
- Compliance with IEC/IEEE standards
Tip: Always mention safety and standards compliance.
6. How do you ensure safety in electrical design?
Sample Answer: Follow IEC, IS, IEEE standards, use protective devices like relays/circuit breakers, proper grounding/earthing, and perform short-circuit studies.
7. What is the difference between earthing and grounding?
Sample Answer: Earthing connects equipment to the ground for safety. Grounding connects electrical systems to a common reference point to stabilize voltage.
8. Tell us about a challenging project you worked on.
Sample Answer: During an internship, I upgraded an old switchgear system, integrating modern digital relays. I analyzed compatibility, redesigned the SLD, and successfully tested the system.
Tip: Use the STAR method (Situation, Task, Action, Result).
9. How do you calculate short-circuit current?
Sample Answer: Use Isc = (MVA × 1000) / (1.732 × V × Z%). Tools like ETAP help improve accuracy.
10. Where do you see yourself in 5 years as an Electrical Design Engineer?
Sample Answer: I aim to specialize in smart grid and renewable integration, take leadership roles, and earn certifications like PMP and Chartered Engineer.
Conclusion
Interviewers look for candidates who not only know technical concepts but can also apply them practically. Preparing for these common questions will help you build confidence and stand out during the interview.
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