Employers and engineers / Recruitment field guide
Transfer schemes, ATS and STS: screening commissioning experience
Distinguish automatic transfer switches, static transfer switches and wider transfer-scheme experience when screening engineers.
01
Name the device and the wider scheme
Automatic transfer switches and static transfer switches use different technologies and may occupy different places in the power architecture. Ask the candidate to describe the project boundary without requesting a confidential single-line diagram.
A person can have extensive device start-up experience without having led the integrated scenario involving generation, UPS systems, controls and downstream loads. Record device and integration responsibilities separately.
02
Use a transition-evidence conversation
Keep the discussion at the level of intent, observation and responsibility. Site-approved sequences and safety procedures govern real testing.
- Which approved operating states and transitions were in scope?
- How were permissives, indications and alarms verified?
- What recorded evidence established the order of events?
- Which party owned device settings, controls logic and design interpretation?
- How was a disputed or incomplete transition investigated and retested?
03
Evaluate the reasoning, not a memorized setting
Different designs have different acceptance criteria and control arrangements. There is no universal transfer time or setting that a recruitment guide should prescribe for every site.
Ask how the engineer checked the requirement before judging a result. WBDG's documentation guidance supports project-specific procedures and acceptance; ASHRAE's L5 description places cross-system behavior in integrated testing.
Quick answers
Common questions
- Does ATS experience automatically cover STS commissioning?
- No. There may be relevant principles in common, but equipment, interfaces and direct experience must be verified separately.
- Why ask about event records?
- An observed transition needs traceable evidence against the approved requirements. Ask what data was captured and how it was interpreted, not only what appeared on a screen.
Further reading
Sources
- WBDG — Commissioning Documents: Process, Contents, and Acceptance
- ASHRAE — Commissioning & Performance Validation
- Vertiv — Commissioning Your Data Center (PDF)
Sources provide industry background. Loadbank Talent’s hiring prompts and editorial checklists are not source quotations or operating procedures.