Role analysis
CxA, QCxP, controls engineer and startup technician
Hiring managers often call all four roles 'commissioning'. The people in them come from different backgrounds and are paid on different markets, so each one needs its own job description.
Founder & Principal Recruiter · Published September 14, 2026
CxA, QCxP, controls engineer and startup technician
A commissioning authority owns the process: plan, scripts, witness points, issue log, owner report. A QCxP is a certified agent who runs and documents testing. A controls engineer builds the BMS and EPMS software the tests run against. A startup technician brings each system online under the plan. Screen and pay each one separately, and hire them in the order the test scripts need them.
Responsibilities
The CxA answers to the owner for the whole commissioning outcome. The QCxP certifies that specific tests were run to standard. The controls engineer is accountable for whether the BMS and EPMS data can be trusted. The startup technician is accountable for safe, correct energization of the equipment in front of them.
One role can't cover for another. A controls engineer who has never witnessed L5 can't run your integrated systems test, and a startup technician can't stand in for a CxA.
- CxA: plan authorship, script approval, issue-log ownership, owner reporting
- QCxP: certified test execution and documentation to a defined standard
- Controls engineer: BAS/BMS platforms, PLC logic, point-to-point checkout, trending
- Startup technician: energization, initial operation, deficiency identification
Screening
For commissioning agents, ask which levels they carried on which systems and what their ISAT failure log looked like. For controls engineers, ask which platforms they configured themselves and how they handled a point database that did not match the drawings. For startup technicians, ask what they have personally energized and what went wrong.
A certification shows someone passed the exam. For the hiring decision, ask for their project history, what failed on site and how they handled it.
Hiring order
Hire these roles in the order the test scripts need them. Commissioning leadership should start while scripts are being written, controls engineers before point-to-point checkout, startup technicians before energization, and operations staff should shadow the work before turnover. If you hire the CxA after the GC's commissioning plan is already moving, your owner-side CxA ends up reviewing decisions that can no longer be changed.
The commissioning engineer
The commissioning engineer does the testing work under the CxA's plan. They review designs and submittals for testability, write test scripts, witness factory and site acceptance tests, run load bank and integrated systems tests, keep the issues log and close each item. At the end they put together the turnover package the owner and operations team use: completed scripts, a closed issues log, trend data from load testing and the as-built sequences of operation.
On smaller projects one person may act as both the commissioning engineer and the CxA.
Commissioning levels
Data center commissioning is usually described in five levels. To judge seniority, ask for the highest level a candidate has personally run.
- Level 1: factory acceptance testing at the manufacturer
- Level 2: delivery, installation and static checks on site
- Level 3: startup and pre-functional testing of each piece of equipment
- Level 4: functional performance testing of connected systems
- Level 5: integrated systems testing at load, including failure scenarios
Sources
By market
Markets
Candidate supply and pay differ by metro. These pages cover the markets where this comes up most.
Questions
Questions
- Do we need an owner-side CxA if our GC provides commissioning?
- Most programs end up with both. The contractor's commissioning team delivers the building and the owner-side CxA accepts it. Without an owner-side CxA, the contractor checks its own work right when schedule pressure is highest.
- What is QCxP certification worth in screening?
- It confirms baseline knowledge of the commissioning process and its terms. It says nothing about which levels the person has run on live projects, so use it as a first filter and make the decision on project history.
- How early should these hires start before turnover?
- Commissioning leadership before scripts are written, controls engineers before checkout begins, and startup technicians in the hiring wave before energization. Set each start date by working back from the turnover date.
- Is a commissioning engineer the same as a CxA?
- No. The commissioning engineer runs the tests. The CxA owns the commissioning plan and process, often on the owner's behalf. On smaller projects one person may do both.
- What background do commissioning engineers come from?
- Most come from electrical or mechanical engineering, MEP contracting, the military (especially Navy nuclear and shipboard electrical), or critical facilities and utilities work in semiconductor fabs, pharma or hospitals.
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Czarina Tabayoyong
Founder and principal recruiter, Critical Path Hiring. Czarina recruits commissioning, MEP, power and critical facilities people for data center builds. She previously recruited cloud and data center architecture talent at AWS Professional Services, and PMO and project delivery talent for hyperscale data center campuses in Texas and Virginia.
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