What should a generator test log record?

The date and start time, how long the set actually ran, what kind of test it was — a routine exercise, a transfer test, a load test — whether it ran under load and at roughly what percentage of nameplate, whether automatic transfer was observed, the fuel level and condition, any alarms or faults with the exact panel message, anything you saw or heard that was not right, the result, and what was done about it. Then who ran it.

How often does an emergency generator have to be tested?

NFPA 110 describes a weekly inspection of the emergency power supply system and a monthly exercise under load for systems within its scope, and this tool shows that baseline with the edition it was checked against. Whether it applies to your set — and at what interval — depends on the code edition your jurisdiction has adopted, the system's classification, the manufacturer's instructions, your facility policy and your authority having jurisdiction. This tool records what you ran; it does not decide what you owe.

Why does running the generator with no load matter?

A diesel set run repeatedly at light load does not get hot enough to burn off unburned fuel and carbon, which accumulates in the exhaust — commonly called wet stacking — and it is one of the more common reasons a generator that has been exercised every month for years fails when it is needed. That is why the log asks whether the run was under load and at roughly what percentage, rather than just how long it ran.

Generator test & run log

Cited baseline

Record generator tests, run time, transfer and issues — one running log per set, printed for the file.

One log per set

A building with two generators has two maintenance histories, and a single sheet interleaving them is a sheet nobody can read when it matters. Add each set once; each keeps its own entries and prints its own log, so “the log for the north generator” is a thing that exists.

Record what actually happened

The duration you really got, the alarm text as the panel showed it, the weep at the upper hose. A log of thirty perfect runs tells an inspector that nobody was looking, and it tells you nothing about a machine whose whole job is to work on the one day you find out.

The load question is the one worth answering honestly. A diesel set exercised repeatedly at light load does not burn off carbon, and that is a common reason a generator with a spotless run log fails under real demand.

Where the intervals come from

EPSS inspection — fuel, oil, coolant, batteries, charger, leaks. Walk the generator without starting it: fuel level and no leaks, oil and coolant levels, battery terminals clean, charger showing float, block heater warm, louvers clear, and the switch still in AUTO. NFPA 110 §8.4.1 (weekly inspection), cited from the 2022 edition; CMS holds certified nursing facilities to the 2010 edition (42 CFR §483.90), and elsewhere the edition your state or AHJ adopted governs. Record: checklist log. Retention: per authority.

Exercise under load — ≥30 min, ≥30% nameplate (diesel). Run the generator under real load for at least 30 minutes at 30% or more of its nameplate rating. Running it unloaded is what causes wet stacking and eventual failure, so light load does not count. NFPA 110 §8.4.2 (monthly load run), cited from the 2022 edition; CMS holds certified nursing facilities to the 2010 edition (42 CFR §483.90), and elsewhere the edition your state or AHJ adopted governs. Record: run log: load, duration, transfer. Retention: per authority.

This is the national consensus baseline, with the edition each figure was checked against. Whether it applies to your building — and at what frequency — depends on the code edition your jurisdiction has adopted, your occupancy, your equipment's listing, the manufacturer's instructions and your authority having jurisdiction. Confirm it with them. This tool records what you did; it makes no determination that any facility is compliant.

The semi-annual EPSS inspection, the load bank test — owed only where the monthly exercises did not meet the NFPA 110 load criteria, and a gap in this log is a reading to find rather than proof that it is owed — and the three-yearly four-hour full-load test for a Level 1 system are separate exercises, usually by a contractor, and nothing here performs or certifies them.

The rest of the round

The two monthly walks that go with this are the extinguisher inspection log and the emergency lighting test log. The compliance calendar puts all of it on dates with the code behind each, and the PM checklist covers the mechanical rounds.

A record of tests you ran. CompliMaint issues no certifications and makes no determination that any facility is compliant — your authority having jurisdiction does that. Everything runs on your device.

Questions people ask

What should a generator test log record?: The date and start time, how long the set actually ran, what kind of test it was — a routine exercise, a transfer test, a load test — whether it ran under load and at roughly what percentage of nameplate, whether automatic transfer was observed, the fuel level and condition, any alarms or faults with the exact panel message, anything you saw or heard that was not right, the result, and what was done about it. Then who ran it.
How often does an emergency generator have to be tested?: NFPA 110 describes a weekly inspection of the emergency power supply system and a monthly exercise under load for systems within its scope, and this tool shows that baseline with the edition it was checked against. Whether it applies to your set — and at what interval — depends on the code edition your jurisdiction has adopted, the system's classification, the manufacturer's instructions, your facility policy and your authority having jurisdiction. This tool records what you ran; it does not decide what you owe.
Why does running the generator with no load matter?: A diesel set run repeatedly at light load does not get hot enough to burn off unburned fuel and carbon, which accumulates in the exhaust — commonly called wet stacking — and it is one of the more common reasons a generator that has been exercised every month for years fails when it is needed. That is why the log asks whether the run was under load and at roughly what percentage, rather than just how long it ran.