A clear weekly-to-annual preventive-maintenance cadence for standby and commercial generators — what falls in each interval, and why the governing standard and your AHJ, not a generic calendar, set the real requirements.
A commercial standby generator is typically maintained on a layered cadence: a brief weekly visual inspection, a monthly exercise run with an automatic-transfer-switch test, more thorough quarterly and semi-annual inspections, and a comprehensive annual preventive-maintenance service that often includes a load bank test. These groupings are a common framework, not a universal rule — the actual tasks and intervals for a given unit are set by the governing standard (such as NFPA 110), the authority having jurisdiction, and the manufacturer’s recommendations, and they vary by facility type.
A common way to organize generator preventive maintenance by interval. Treat it as a starting point and adjust every item to what your governing standard, AHJ, and manufacturer require.
Often on-site staff
Technician or trained staff
Service technician
Service technician
Service technician
Per manufacturer
These groupings are a framework, not a directive. A hospital, a data center, and a small office are not held to the same bar — and the same unit can carry different requirements depending on the facility it protects.
Three authorities set what your schedule must actually contain, and the cadence above only approximates them. The governing standard — most often NFPA 110 for emergency and standby power supply systems — defines the testing and maintenance a facility of a given type must perform. The authority having jurisdiction (AHJ) — the inspector or official who enforces the code locally — has the final say and can require more. And the equipment manufacturer specifies service intervals for the engine, controls, and transfer switch, many of them tied to runtime hours rather than the calendar.
Where these differ, the more stringent requirement wins. This is why no honest maintenance schedule can be one-size-fits-all, and why any vendor claiming their software “makes you compliant” is overselling. Software can hold and run the schedule; the requirements come from the standard, the AHJ, and the manufacturer.
For the requirements themselves in plain English, see the platform overview and its section on what the standards actually require.
Six steps to turn the framework above into a real, per-unit schedule you can run and defend.
Record make, model, serial, kW rating, automatic transfer switch, fuel type, install date, and current runtime hours for each generator. The schedule is built per unit, because a 40 kW office standby and a paralleled hospital plant are not maintained the same way.
Determine which standard applies to each facility — most standby power falls under NFPA 110 — and confirm what the authority having jurisdiction expects. This, not a generic calendar, sets the mandatory tasks and intervals, and it varies by facility type.
Layer in the engine and controls manufacturer’s service intervals — many are tied to runtime hours as well as calendar time. Where the manufacturer and the standard differ, follow the more stringent of the two.
Sort every task into weekly, monthly, quarterly, semi-annual, and annual buckets, plus multi-year and runtime-based items. Use the framework on this page as a starting point and adjust it to what your standard, AHJ, and manufacturer require.
Decide who performs each cadence — weekly visuals often fall to on-site staff, while quarterly and annual service is a technician’s job — and generate the work orders so nothing depends on someone remembering.
Record readings, findings, photos, and pass/fail results against the specific unit, attributed to the person who did the work, at the time they did it. That record is what you produce when a facility, insurer, or auditor asks.
A schedule only works if the work surfaces before it slips and the record is captured when it is done. That is the part generator service software automates.
Hold each unit’s own PM schedule — configurable per unit or unit type — to match what the standard, AHJ, and manufacturer require, instead of one blanket reminder for the whole fleet.
One fleet-wide view of what needs attention now, what is on deck, and what has slipped past its interval — plus a rolling forecast so you can plan crews and parts.
When a PM comes due, the work order is created with the unit, checklist, and history already attached — no one retypes the equipment or rebuilds the scope.
Readings, photos, and pass/fail land against the specific unit, attributed to the technician, in an append-only record you can produce on demand.
Most programs use a layered cadence: a weekly visual inspection, a monthly exercise run with an automatic-transfer-switch test, quarterly and semi-annual inspections, and a comprehensive annual preventive-maintenance service that often includes a load bank test. The actual intervals are set by the governing standard (such as NFPA 110), the authority having jurisdiction, and the manufacturer — and they vary by facility type.
A scheduled exercise run — often monthly — verifies the unit will start and run, and it is the routine most programs build around. The exercise should place a meaningful load on the engine; a diesel that only ever runs unloaded tends to wet-stack. Confirm your required exercise interval and load with the governing standard, the AHJ, and the manufacturer for your specific unit.
A load bank test applies an artificial load so the unit can be run at a meaningful percentage of its rating. It is commonly performed annually where the routine monthly exercise does not reach the load the governing standard requires. The exact interval and load threshold are set by that standard and your AHJ — not by a generic schedule.
No. Following a good cadence is diligence, but compliance is judged against the governing standard and the authority having jurisdiction, and it requires a permanent record you can produce on demand. A schedule tells you what to do; the record proves who did it and when. Software can systemize both, but it does not decide compliance for you.
Weekly visual checks are commonly handled by trained on-site staff, since they are largely observational. The monthly exercise and transfer-switch test can be run by trained staff or a technician. Quarterly, semi-annual, and annual service — fluid changes, load bank testing, and detailed inspection — is qualified-technician work. Match the task to the competency, and record who performed it.
For each service: the date, the unit it was performed on, the person who performed it, the readings taken (voltage, frequency, oil pressure, temperatures, transfer times), any load bank results with pass/fail, findings, and photos. Kept as an attributed, append-only record — one that cannot be silently edited later — it becomes the evidence an auditor or surveyor accepts.
Start a free trial and configure a cadence per unit, or book a demo and bring the fleet you maintain today.