Generator testing under NFPA 110: weekly, monthly, annual, and the 3-year test
NFPA 110 sets the ITM schedule for emergency power supply systems: weekly inspections, a monthly 30-minute test under load at no less than 30 percent of nameplate, an annual load bank test where monthly loading falls short, and a 4-hour test every 3 years for Level 1 systems. The full schedule and the records that prove it ran.
By Hovermarks team
Quick answer. NFPA 110 requires the emergency power supply system (EPSS), generator set, transfer switches, and supporting systems included, to be inspected weekly, exercised monthly for at least 30 minutes under load at no less than 30 percent of nameplate kW (or to the manufacturer's recommended exhaust temperature), given an annual load bank test where the monthly test cannot reach that loading, and for Level 1 systems, a 4-hour test at least once every 3 years. Records of every inspection and test are required, and they are what an AHJ or accreditation surveyor actually asks for.
Hospitals, data-adjacent facilities, high-rises, and any building whose life-safety systems depend on standby power run under NFPA 110, usually pulled in by the fire alarm and life-safety codes. The schedule is not complicated; keeping the evidence straight across weekly, monthly, annual, and triennial cycles is where programs fail their surveys.
The schedule
- Weekly: inspection. The EPSS and its appurtenant components are checked: fuel level and system, lubrication, cooling, battery and charger, exhaust, and the general condition of the set and transfer equipment. A walk-round with a checklist, not a test run.
- Monthly: 30-minute exercise under load. The generator runs for at least 30 minutes carrying no less than 30 percent of nameplate kW, or loading that reaches the manufacturer's recommended exhaust gas temperature. Transfer switches are exercised as part of the monthly routine.
- Annually: load bank where the building cannot supply the load. Diesel sets whose monthly runs fall short of the 30 percent threshold take a supplemental load bank test each year, stepping up through higher loadings, so wet-stacking does not quietly degrade the engine.
- Every 3 years (Level 1): the 4-hour test. Systems where failure could cost life or serious injury run a continuous test of at least 4 hours under load at least once every 36 months.
Level 1 versus Level 2 matters throughout: Level 1 systems (life safety) carry the stricter expectations, and your fire alarm plan or occupancy code decides which level applies.
The records an AHJ asks for
Per generator and transfer switch: the weekly inspection trail, each monthly test with run time, loading achieved, and how the loading was evidenced (kW reading or exhaust temperature), the annual load bank report where applicable, and the date and result of the last 3-year test. Gaps in the monthly sequence are the finding surveyors write most, because a missing month cannot be backfilled honestly.
Where Hovermarks fits
Hovermarks ships a monthly NFPA 110 load-exercise template out of the box: the generator and each transfer switch are QR-tagged assets, the monthly run is a scheduled checklist with the readings captured as structured fields, and the complete ITM history sits on the asset for the surveyor. Each asset carries one recurring schedule and next-due date today, so the weekly walk-round and the annual and 3-year tests are not yet tracked on their own due dates. The fire safety solution shows how the generator schedule sits alongside NFPA 10, 25, and 72.