HV/MV Sector Interviews: Technical Questions Every M&E Professional Should Prepare For

HV/MV Sector Interviews: Technical Questions Every M&E Professional Should Prepare For

If you are preparing for an interview in the High Voltage (HV) or Medium Voltage (MV) sector, you already know it is not the kind of meeting where you can wing it. Employers in Ireland’s Mechanical and Electrical (M&E) industry want candidates who are sharp, confident and ready to back up their CV with real-world examples.

At Breagh Recruitment, we speak with candidates and employers across the sector every day. We know the questions that regularly come up and the mistakes that can cost you the job. Here is the straight-talking advice you need to walk into your next HV/MV interview ready to impress.

Focus on Single-Line Diagrams

One of the most common technical tests is being asked to explain or break down a single-line diagram. Interviewers are not looking for hesitation or guesswork. They want to see clarity in your explanation and an understanding of how the system operates in practice.

If you cannot walk them through a diagram confidently, it will raise red flags straight away. This is one area to revise thoroughly before your interview.

Be Ready to Discuss Equipment Selection

Expect questions around transformers, switchgear and cable runs. Employers want to know how you size and specify equipment for a given project and why you made those choices. Waffling will not cut it. You need to show you understand both the technical reasoning and the practical application.

Own the Grid Connection Process

Grid connections are often a sticking point, so be prepared to explain how you have managed them from start to finish. This could include liaising with the Distribution Network Operator (DNO), planning timelines, and overseeing commissioning.

Remember, they do not want to hear that you were “involved” in the process. They want to know what you actually did and the outcomes you delivered.

Show How You Handle Integration with Mechanical Services

Another area you may be tested on is how you coordinated MV electrical systems with mechanical services. This is about avoiding clashes on congested sites and ensuring smooth commissioning. Being able to speak about clash detection, BIM tools or manual coordination, and how you worked with other teams, shows strong practical experience.

Demonstrate Problem-Solving Under Pressure

Ultimately, the technical questions are not just about knowledge. Employers want to see how you think, how you approach risk, and how you solve problems when things go wrong. Structure your answers clearly: what was the context, what action did you take, and what was the result?

Do not shy away from sharing messy project examples. These are often the most powerful stories if you can show how you resolved them and what you learned.

Final Thoughts

An HV/MV interview is a chance to prove you are more than just a CV. Preparation is key. Employers in Ireland’s M&E sector want to see confidence, ownership and a clear track record of delivering under pressure.

At Breagh Recruitment, we help M&E professionals across Ireland secure roles with leading contractors and developers. If you are looking to take the next step in your career, get in touch with our team today.