This guide covers the records an owner should keep for an emergency diesel generator: what they are, what each entry should say and how to keep them in good order. Requirements differ by country and by type of facility, so check with the authority that applies to you.
Why records matter
Records show that the set was maintained and tested as planned. They give evidence to inspectors, insurers and facility owners, and they provide trend data for engineers: slow starts, rising temperatures or falling battery voltage are visible only if they are written down.
In health care, data processing, water and industrial sites, regulators or customers may set minimum testing and record keeping rules. In the United States, standards such as NFPA 110 set expectations for emergency power systems, and many other countries apply similar rules or adopt them by reference.
Types of tests
Most programmes include several kinds of test. A no-load or light-load exercise run checks that the set starts and runs. A loaded run, either on a load bank or on the building load, shows that the set carries power at the needed level. A transfer test proves that the automatic transfer switch moves the load to the set and back.
Longer annual runs and fuel system checks complete the cycle. Each test should be recorded as its own entry with its own result.
What each log entry should contain
A good entry shows the date and time, the name of the person, the set identity, the type of test, the hour meter reading before and after, the load, key readings such as oil pressure, coolant temperature, voltage, frequency and battery voltage, and the result. It should also note any alarms, leaks, unusual noise or anything else that was seen.
Add the time to start and time to take load for each start. These are among the best early indicators of trouble.
Transfer switch records
The automatic transfer switch is as important as the generator. Record every transfer test with the time delay settings, the time to transfer and the retransfer to utility. Note whether the switch was exercised under real load and whether any manual bypass was used.
Keep records of ATS inspections, contact checks and control setting reviews. If the settings change, the new values and reason should be written down.
Fuel records
Diesel in storage ages, collects water and grows microbes. Record fuel level checks, water drain results, fuel quality test results, filter changes and fuel deliveries. If the fuel is polished or replaced, write down the date and the volume.
Our guide to how long a diesel generator can run continuously explains why fuel supply planning is part of readiness, and why a record of tank levels is useful in an emergency.
Battery and starting system records
Starting failure is the most common cause of standby generator failure. Keep records of battery voltage, charger operation, electrolyte checks where relevant, load tests of batteries, cable and terminal inspections and replacement dates.
Batteries should be replaced on a schedule, not only after failure. A record of installation date makes the schedule possible.
Deficiencies and corrective actions
Every test will sometimes find a problem. What counts is whether the problem is recorded, assigned and closed. Keep a deficiency list with date found, description, owner, due date and closure date. Auditors look closely at open items and at items that recur.
If the system cannot meet its duty until a repair is made, record the interim measures, such as a temporary generator, extra staff or notices to affected parties.
Retention and format
Keep records for as long as the authority, insurer or contract requires, and at least for the life of the set. Paper logbooks are fine if they are legible, bound and signed, while electronic systems should have access control, back-ups and a record of changes.
Whatever the format, store records where they can be found quickly. A cabinet in the generator room with a key held by the facility manager is better than a folder in somebody’s car.
Common record keeping mistakes
The most frequent mistakes are logs filled in weeks later from memory, entries with the same values every month, missing hour meter readings, no record of who performed the test and tests that were run but never written down. Each one weakens the value of the whole log.
Make the log easy to complete. A one-page form at the set, a clear list of readings and a habit of filling it out during the test reduce errors. Review a sample of entries each quarter to confirm they are complete and credible.
Digital versus paper logs
Paper logs are simple and robust, but they are hard to analyse. Electronic logs, whether a spreadsheet or a maintenance system, allow trend charts, reminders for overdue tests and quick searches during audits. The best choice is the one that your staff will actually use every month.
If you move to electronic records, keep copies of the old paper logs and note the date of the changeover so the history stays continuous.
Being audit-ready
Before an inspection, review the last year of records for gaps. Look for missed tests, entries without values, unexplained changes and open deficiencies. Fix what can be fixed and prepare an honest explanation of what cannot.
Our installation guide and the sizing chart help new projects set the baseline data that later records are compared with.
Who writes this
Testing programmes and their records are what our service planners help facility managers organise. Compiled by the USP&E service team of USP&E, a contractor that carries EPC and O&M scopes directly rather than reselling them, and that cites 25,000 MW contracted since 2002, 150+ power projects in 45+ countries and 24+ years in the field. Learn how our operations and maintenance team supports standby power.
Offices: Colorado Springs (1755 Telstar Dr, Suite 300), Knoxville (800 S Gay St, Suite 700), London (162-168 Regent Street), Johannesburg (22 Kildoon Rd, Bryanston), Cape Town (31 Brickfield Road, Woodstock) and China (No. 1 Ningzhou Road, Wuxi). Regions: USA | AFRICA | UK | UAE | CHINA. ISO 9001 and ISO 45001 certified.
Questions about emergency generator records
How often should an emergency generator be tested?
Many programmes use monthly exercise runs and an annual longer or loaded test, but the schedule must follow the rules that apply to your facility and the manufacturer’s advice.
What is the most important record?
The test log with readings, because it shows trends and proves that the set was exercised.
Do I need to record transfer switch tests separately?
Yes. The switch is part of the emergency system, and its operation and settings need their own records.
How long should records be kept?
As long as the authority, insurer or contract demands, and in practice for the life of the set.
Need help with a testing programme?
Send us the site type, set details and current logs, and our service engineers will suggest a test schedule and a clear record format.
Phone +27 10 822 2324, email info@uspeglobal.com with your site data, or go through the service enquiry form. See the diesel generator inventory for units available now.