For a facility manager, a backup generator can be easy to overlook when it starts reliably during routine checks. The real test comes when utility power fails and critical equipment, safety systems, or business operations depend on the emergency power system.
Without a consistent testing schedule and accurate records, hidden faults can often go unnoticed until the generator is needed most. Understanding NFPA 110 generator testing requirements helps facility managers to organize inspections, schedule operational tests, maintain accurate records, and prepare for compliance reviews.
This checklist by Curtis Power Solutions covers the key testing activities, documentation practices, and compliance checks to include in your facility’s emergency power maintenance program.
NFPA 110, Standard for Emergency and Standby Power Systems, establishes requirements for the installation, performance, maintenance, and testing of emergency power systems.
The table below includes a brief overview of the Routine Maintenance and Operational Testing required under NFPA 110.
The table provides general guidance. Exact requirements for a particular generator installation depend on the applicable NFPA 110 edition, manufacturer instructions, and the Authority Having Jurisdiction (AHJ).
See our complete guide on NFPA 110 Requirements for more information.
The checklist below covers the NFPA 110 generator testing requirements for emergency power supply systems (EPSS) that facility managers must take care of.
Weekly procedures focus on visual and operational readiness to ensure a seamless cold start when normal power fails. A cold start means the EPS starts and accepts full load without any manual pre-warming or idle period.
Visual Inspection - Check for fluid leaks (oil, coolant, fuel), belt wear, loose connections, and structural integrity.
Monthly Testing requires exercising the entire generator system under specific load conditions to prevent "wet stacking" (carbon buildup from unburned diesel fuel).
Duration - Run the generator for at least 30 continuous minutes under load, followed by a 5 minute cool-down period.
Load Criteria - Apply at least 30% of the generator's nameplate kW rating or the engine must reach the minimum exhaust gas temperature recommended by the manufacturer.
Documentation - Keep a record of complete operational data, such as oil pressure, water temperature, output voltage, and frequency.
You can also download our NFPA 110 Forms to get your maintenance and testing schedules, forms, and logs for recordkeeping.
An automatic transfer switch (ATS) moves designated loads between the normal utility supply and the emergency power source. The required ATS testing includes:
Monthly Initiation - The monthly operational test should be initiated by simulating a power failure at the ATS.
Time-Delay Verification - Document the applicable time-delays for engine start, transfer to the emergency source, retransfer back to utility power, and engine cool-down.
When the monthly load testing does not meet the recommended 30% nameplate capacity during monthly tests, you may need a supplemented load bank test. For NFPA 110, 2025 edition, this includes running the generator at 50% load for 30 minutes, then increasing to 75% load for 1 hour (1.5 hours total run time).
Compliance to NFPA 110 requires tracking several longer-term maintenance milestones and fuel health audits too, this includes:
Triennial Testing (36 Months) - Level 1 systems must undergo a continuous, full-system run of at least 4 hours (or the duration of its designated Class specification).
Annual Fuel Quality Test - Sample fuel from the bottom of the storage tank to ensure it remains viable, clean, and reliable for emergency backup power systems
Breaker Exercising - Exercise circuit breakers annually (or every 3 years for breakers rated greater than 1,000V).
Record Retention - Maintain required written logs of all inspection and testing data on-site for immediate inspection by the AHJ.
Healthcare facilities may also have requirements under NFPA 99, accreditation standards, or other adopted regulations. Keeping a forward-looking calendar of every applicable test, inspection, and maintenance deadline helps ensure compliance.
A generator testing log provides evidence that the facility has carried out its scheduled inspections, exercises, and maintenance. It also helps technicians identify recurring problems and compare performance over time.
Your NFPA 110 generator testing form or equivalent record should capture the following information, as applicable:
Equipment details - Generator identification, location, rated capacity, and associated transfer switches.
Test details - Date, start and finish times, test type, duration, and responsible technician.
Operating conditions - Load level, voltage, frequency, and relevant engine readings.
Transfer switch results - Transfer and retransfer performance, alarms, and observed time delays.
Inspection findings - Battery and charger condition, fuel status, leaks, alarms, and visible defects.
Issues and corrective actions - Failed tests, unusual readings, repairs required, and follow-up dates.
Verification - Technician name, sign-off, and any required review or approval.
The record should reflect what actually happened during the test and not simply indicate that generator testing was completed.
Even when a testing schedule exists, gaps in execution or documentation can undermine system readiness.
Watch out for these common mistakes that facility managers can make:
Testing without sufficient load - A successful start does not establish that the generator can support the required load.
Overlooking transfer equipment - A functioning generator cannot supply emergency loads as intended if the transfer system fails.
Treating every installation the same - Testing requirements can differ according to the applicable standard, system classification, and facility regulations.
Leaving faults unresolved - Repeated alarms, abnormal readings, and failed tests need documented investigation and corrective action.
Keeping incomplete records - Missing test dates, load readings, durations, or repair details can make it difficult to demonstrate that required procedures were followed.
Ignoring manufacturer guidance - Routine maintenance and testing must account for equipment-specific instructions as well as applicable code requirements.
Review the entire EPSS, not just the generator engine. Fuel systems, controls, batteries, transfer switches, and supporting equipment all contribute to the reliability of emergency power systems.
Before an inspection or compliance review, compare your maintenance program with the applicable NFPA 110 edition, adopted codes, manufacturer documentation, and the requirements of the applicable AHJ.
Use this preparation checklist for your compliance review:
Confirm the applicable requirements - Identify the adopted standard edition, EPSS classification, and any additional regulatory obligations.
Review the testing schedule - Check weekly inspections, monthly exercises, transfer switch tests, and any required extended-duration or supplemental tests.
Organize records - Gather completed testing forms, service reports, maintenance logs, and evidence of corrective actions.
Check outstanding issues - Identify unresolved faults, missed tests, overdue maintenance, and planned remedial work.
Verify system documentation - Ensure relevant equipment manuals, procedures, and contact details are available to authorized personnel.
Coordinate with qualified service personnel - Arrange any specialist testing, repairs, or technical assessments needed before the review.
Do not wait until an inspection is scheduled to discover missing records or overdue tests. Perform regular reviews to identify gaps early and keep the programme on track.
Meeting NFPA 110 generator testing requirements isn’t just about maintaining a calendar of inspections. A dependable emergency power system also requires consistent testing, accurate records, timely maintenance, and attention to the entire system.
At Curtis Power Solutions, we support businesses and facilities with our power generation expertise, including generator rental, service, maintenance, and testing support. If you need help reviewing your generator's maintenance programme or planning testing for your facility, Contact Curtis Power Solutions to discuss your requirements.
Generator testing requirements for NFPA 110 includes:
Weekly - Visual inspection of fluids, battery, and components.
Monthly - Run for 30 minutes under a minimum 30% nameplate load.
Annually - A 1.5-hour load bank test (if the monthly 30% load threshold is not met).
Triennially (Every 3 Years) - A continuous 4-hour full-load test for critical (Level 1) systems.
An NFPA 11o generator testing checklist should include visual inspections, operational run tests, load bank requirements, and required maintenance and testing records.
Yes, NFPA 110 requires monthly generator load testing for a minimum 30 minutes. The generator must operate at a minimum of 30% of its standby nameplate kW rating or if 30% load cannot be reached, the generator must draw enough building load to meet the manufacturer-recommended minimum exhaust gas temperature.
For NFPA 110 compliance, facility managers should maintain written records of all inspections, testing, maintenance, and repair activities for the emergency power system.
No. NFPA 110 applies to emergency and standby power systems when required by applicable codes, standards, or the Authority Having Jurisdiction. Optional standby systems may fall under different requirements.
Facility owners and operators are generally responsible for ensuring required testing and maintenance are completed, while the AHJ determines and enforces applicable code requirements.
Facility managers can prepare for an NFPA 110 compliance inspection by ensuring regular testing and physical inspections are performed on time and keeping records of all relevant data.