Interview questions: Electrical Commissioning Engineer

What does this hire really come down to?

The scope covers switchgear, transformers, protection settings, generators, UPS, and transfer schemes. Some firms expect the engineer to direct testing technicians, others expect hands on execution. Ask which, and who held switching authority. A training certificate in NFPA 70E, the electrical safety standard, does not by itself show they are qualified for a task. Your company decides that.

Where do we find these candidates?

Candidates come from electrical contractor startup teams, independent testing companies, commissioning firms, and utility or industrial plants. Testing company people go deep on equipment, while contractor people know interfaces with construction.

Energization questions

Walk me through the checks before first energization of medium voltage switchgear. Who signed the permit, who operated, and where were you standing?

What did the protection settings test show, and how did you confirm the relay matched the study? Tell me about a mismatch you found and who corrected it.

Describe a transfer test from utility to generator. What did you monitor, and what would have made you abort?

Integrated test questions

How did you stage load for a UPS and battery test, and what did you do about heat? Describe a failure in an integrated test and how you isolated the cause.

Which parts of the test did the vendor run, and which did you insist on witnessing?

Safety and authority

Tell me when you refused to proceed on electrical work. Who held switching authority on your last job? Ask about the OSHA Outreach card they carry only to learn what it is: a course completion card, not proof they can work on energized equipment.

Questions on documentation and handoff

What records did you keep for each piece of equipment, and who reviewed them? How did you record settings so operators could restore them after maintenance?

Which problems showed up only during the integrated test? Describe how you traced one to its cause.

Reading the credentials honestly

NETA certification applies to individual technicians employed by accredited companies, at Levels 2 to 4, and you should confirm current status and what they actually tested. A journeyman license depends on jurisdiction and scope. Neither tells you whether they can run an integrated systems test.

Questions on generators and power quality

What did you check on a generator before the first start, and what did a load bank test show about regulation and heat? Tell me about a paralleling or controls fault and how you found it.

How did you test a static transfer switch or automatic transfer scheme for loss of one source? What would you do if a breaker failed to open on command?

Questions on working with others

How did you coordinate with the mechanical team when load banks needed cooling? Which of your contractor's technicians did you trust, and why? Describe a time you disagreed with a manufacturer's field representative and who turned out to be right.

Finish by asking what they would want in place before they arrived on your site. Good answers include approved settings, a switching procedure, and a named person who can authorize operation.