Technical1 min read
How often should you load-bank test your standby generator?
NFPA 110 sets a floor. Your operations should set the ceiling.
By Megawatt Maintenance
Short version: once per year, at minimum, at 30% of nameplate or higher for the prescribed duration. That's the NFPA 110 baseline for Level 1 emergency power systems. Healthcare facilities under NFPA 99 follow adjacent rules.
But the floor isn't the answer for everyone. Here's the cadence we actually recommend, by use case.
Mission-critical standby (data centers, hospitals)
- Monthly exercise under building load.
- Quarterly inspection.
- Annual load bank to NFPA 110 — 30% / 50% / 75% / 100% step load, documented with a printed curve.
Continuous-duty industrial (bitcoin, behind-the-meter)
- Treat the engine like a prime mover, not a backup.
- PM cadence built around runtime hours, not the calendar.
- Load bank only after major work — top-end, in-frame, controls.
Standby for commercial property
- Annual load bank.
- Monthly automatic exercise via the controller.
- Visual + fluid inspection quarterly.
The point of load bank testing isn't to stress the engine — it's to verify your whole standby system can carry the load you expect when the utility goes away. Document everything.