Generator inspection, exercise and load tests
A reading of NFPA 110 8.4 as it is commonly cited on an inspection report. The reading explains the section; it does not certify a building or close a citation. The inspector's finding and the code text govern.
MatchExact section: the decoder holds a reading for NFPA 110 8.4.
Evidence reviewReading prepared from the published text, NFPA 110 2025 edition; readings dated Oct 14, 2026; line-by-line source check pending. Text: NFPA free access (nfpa.org).
AdoptionWhether this standard is in force depends on the state or city that adopts it, and on the edition adopted. The decoder reads it against any of the 51 state records.
What it coversWeekly inspection of the emergency power supply system; a monthly exercise under load for at least 30 minutes (diesel: at least 30% of nameplate or the manufacturer’s minimum exhaust temperature); where the monthly runs cannot reach that load, an annual supplemental test of 50% of nameplate for 30 minutes, then 75% for 60 minutes; transfer switches operated monthly; Level 1 systems also run for 4 hours (or their class duration if shorter) at least every 36 months.
What usually closes itKeep the weekly and monthly logs; order the annual supplemental load test if the monthly load falls short; schedule the 36-month test for Level 1 systems.
Who can do the workGenerator service contractor; trained in-house staff for the weekly inspection
Proof at re-inspectionWeekly and monthly logs; load test reports.
Questions to ask next: which edition and section the finding is written against, in writing; what exactly was observed and what the inspector expects at re-inspection; the correction deadline on the notice. Disagree with the reading of the code? Ask the inspector for the section and edition in writing, then the fire or building official for a written interpretation.