Commissioning is the controlled energize-and-verify of a three-phase UPS, not the install. Here is what a proper commissioning covers, in the order it happens, and why skipping it costs you the warranty.
These two jobs get confused, and the confusion causes problems. A licensed electrician installs the UPS: sets it in place, lands the input and output feeders, connects the battery cabinet, and terminates the cabling to code. That is electrical work, and it ends with a unit that is wired but de-energized.
Commissioning is the next step, and it is a different discipline. It is the controlled process of energizing the system and verifying that every subsystem behaves the way the design intends, usually performed by a factory-trained field engineer, often as a condition of the warranty. The electrician proves the wiring is correct. The commissioning engineer proves the UPS is correct. On a three-phase system the two roles are almost never the same person, and they should not be.
Nothing gets powered until the static checks pass. With the system dead, the engineer works through a checklist that is mostly about catching install errors before they become faults under load.
A torque audit on power terminations comes first, loose lugs are a leading cause of UPS fires, and a torque wrench with a witness mark is the only honest way to confirm them. Phase rotation is verified on the input so the rectifier and any bypass source see the sequence they expect. Insulation resistance is checked with a megger where the manufacturer calls for it, to catch damaged cable or a tracking path before energization. The engineer confirms the settings and configuration against the design: voltage, frequency, bypass thresholds, battery parameters. Finally, battery polarity and connections are verified cell-string by cell-string, reversed polarity on a DC bus is a destructive, expensive mistake, and it is found here or not at all.
Energizing a double-conversion UPS is a sequence, not a switch. Each stage is brought up and confirmed before the next.
The rectifier soft-starts, ramping its draw so it does not slam the upstream breaker or a generator with inrush. The DC bus comes up to its target voltage and is checked for ripple and balance. The inverter starts and synchronizes to the bypass reference, building a clean output in phase with the source. The static bypass is synchronized so a transfer either way is glitch-free. Only then is the load transferred onto the inverter. At each step the engineer is reading meters and watching for alarms, not just pushing buttons, the value of commissioning is the verification between the steps.
The battery is the part most likely to fail you when it matters, so it gets its own attention. The engineer confirms charger output, float and boost voltage, current limit, temperature compensation, and verifies the string voltage and per-block readings are even. A weak or reversed block shows up here.
Then come the functional tests, which prove the UPS does what it is for. Transfer to and from static bypass is exercised in both directions. A loss-of-utility test simulates a real outage so the system rides through on battery with no break to the load. Alarms are triggered and confirmed at the panel. And the comms and monitoring path is proven end to end, SNMP card, network management, dry contacts, and shutdown signaling to whatever it protects. A UPS that carries the load but cannot raise an alarm is only half commissioned.
The final stage puts real or simulated load on the system and watches it hold. A load bank lets the engineer verify the UPS carries rated kW, that the battery delivers its rated runtime, and that thermals stay in spec.
For a multi-module or parallel UPS there is extra work. The engineer confirms the modules share load evenly, an imbalance points to a sync or sense-lead fault, and then proves the N+1 redundancy behaves as designed: pull a module and the rest must pick up the load without a transfer to bypass. That single test is the whole point of a parallel system, and it is the one most often skipped. (For how the redundancy schemes differ, see N, N+1 and 2N; sizing the modules is covered in how to size a three-phase UPS.)
Commissioning ends with documentation: a signed report, the as-left settings record, battery and charger readings, and the test results. That record is the baseline every future service visit measures against.
Most three-phase UPS manufacturers make factory-authorized startup a condition of the full warranty. Energize the unit yourself and the warranty can be reduced or voided before the system ever carries load. There is engineering logic behind the rule, not just paperwork: the startup checks catch the install errors, loose terminations, reversed battery, wrong settings, that would otherwise turn into a warranty claim or a failure six months in. Proper commissioning protects the manufacturer’s warranty and protects your uptime, which is the same thing in the end. Tell us the make, model and site, and we will arrange commissioning by a factory-trained engineer.
Installation is the electrical work, an electrician sets the unit, lands the feeders and battery, and terminates the cabling to code. Commissioning is the controlled energize-and-verify that follows, usually by a factory-trained engineer, confirming every subsystem behaves as designed. The electrician proves the wiring; the commissioning engineer proves the UPS.
Yes. Most manufacturers require factory-authorized startup as a condition of the full warranty, and the pre-energization checks, torque audit, phase rotation, battery polarity, settings, catch install errors that would otherwise become faults under load. Self-energizing a three-phase system risks both the warranty and the equipment.
With the system dead, the engineer runs a torque audit on power terminations, verifies input phase rotation, checks insulation resistance with a megger where required, confirms voltage/frequency/bypass and battery settings against the design, and verifies battery polarity and connections string by string before any power is applied.
After confirming the parallel modules share load evenly, the engineer pulls one module and verifies the remaining modules carry the full load without transferring to bypass. That test proves the N+1 redundancy actually works, it is the whole point of a parallel system and the step most often skipped.
Tell us the application and we will come back within one business day, sizing, the right system, install and a price. Three-phase installs usually need a licensed electrician, so let us know if you have one.