NFPA 110

WINCO standby generators are designed to provide the electrical power demanded in modern life. Hospitals, nursing homes, utility and emergency response facilities must remain operational during power failures because of the risk to human life and well-being. NFPA 110 is a standard for generator performance during a power failure. Other NFPA standards specify which facilities are required to obtain emergency power supply systems (EPSS). Care should be taken to determine the proper EPSS requirements before bidding projects because NFPA 110 requirements will materially affect your bottom line.

The following outline of NFPA 110 standards is not a substitute for advice from a licensed electrician. It is intended as a general outline of NFPA 110 generator performance requirements. Standards and practices are constantly evolving. Contact your licensed electrician, local fire marshal or the building department for additional information. It is essential to remember that the local authority having jurisdiction has the ultimate responsibility to approve specific equipment for any given application.

The emergency power supply system (EPSS) is the engine generator set that provides emergency electrical power in the advent of a utility disruption. When reviewing design requirements for an NFPA 110 EPSS, it is essential to obtain the following three pieces of information that are required.

Class: Specifies the minimum time (hours) that the generator system must be able to provide full output without being refueled. Off-site storage of fuel is generally not allowed especially if it is likely that disruptions in off-site fuel sources are likely. The most common example would be a natural gas generator where an earthquake is likely to break natural gas lines. LP gas and diesel are the most common emergency generator fuel sources for NFPA 110 installations. Diesel systems are allowed to share fuel tanks with other equipment as long as the combined consumption will allow the generator to meet its class requirements. Vapor withdrawal LP gas systems require a dedicated tank for the generator. Make sure in frigid environments to properly account for slower vaporization rates in extreme cold. Liquid withdrawal systems may be required in some environments.

Type: Specifies the maximum amount of time (seconds) before the generator system must be able to provide full output to the designated load. Common designations are Type U (uninterruptible), Type 10 (10 sec), Type M (manual stationary) etc. Most WINCO and WINPOWER emergency generator systems are configured to meet Type 10. WINCO and WINPOWER do not manufacture Uninterruptible Power Supply (UPS) equipment, but our generators may be incorporated as secondary power in applications where UPS are required.

Level: Specifies the equipment features and capabilities required for each application. NFPA 110 has two levels.

Level 1: These generator packages are required when the loss of electrical power could result in loss of human life or serious bodily injuries.
Level 2: These generator packages are required when electrical power is less critical to human health and safety.

NFPA 110 establishes performance standards for the critical components of the generator system in order to provide the most reliable emergency generators. WINCO carefully meets or exceeds NFPA 110 standards to provide a product that will meet the most demanding applications head on.

Starting Systems: Meticulous care is given to the starting system in each WINCO generator to help ensure it will start when needed. The key differences between NFPA 110 and standard systems are outlined in this section. WINCO starting systems meet or exceed the NFPA 110 standards in the table.

Starting: Each WINCO generator is an electric start. We use a cycle crank system for Level 1 and Level 2 installations because we have determined it provides the best process to ensure reliable starting each time while preserving the life of critical starting equipment. After receiving the start signal, the generator cranks 15 seconds and then rests 15 seconds. The generator will attempt a maximum of three crank cycles before it will lock and and go into alarm.

Batteries: Each battery is generally sourced locally. The size recommended is available on the specification sheet for the appropriate model. The batteries are sized to be able to crank the engine through two complete lock out cycles from a full charge. The batteries are not to be installed until the battery charger is powered and properly configured to maintain the system.

Battery Charger: Each WINCO NFPA 110 generator has an upgraded SENS battery charger properly sized to the specifications of the table below. Each battery charger is capable of charging a completely discharged battery without damaging it. A DC voltmeter and ammeter are included in the battery charger. A charger fail contact comes standard which provides early warning of a battery charger failure before the battery is completely depleted.

Starting System Requirements Level 1 Level 2
Battery Unit X X
Battery Certification X NA
Cycle Cranking X or O O
Cranking Limiter Time-Outs    
   Cycle Crank (3 Cycles) 75 sec 75 sec
   Continuous Crank 45 sec 45 sec
Float-type Battery Charger X X
   DC Ammeter X X
   DC Voltmeter X X
Recharge Time 24 hr 36 hr
Low battery voltage alarm contacts X X
X: Required. O: Optional. NA: Not Applicable.


Control System: NFPA 110

Each WINCO liquid-cooled emergency generator uses a sophisticated microprocessor control system that carefully monitors the generator system and provides warnings when maintenance is required. The main control panel is located on the generator set and visually displays performance data. It also monitors key performance parameters to provide early warning if a mechanical or electrical problem develops. The main controller will automatically shut down the system if necessary to help protect the equipment and facility from damage. More details are available in the emergency generator specification sheets. The remote annunciator is mounted in an area of the facility (IE nurse's station) and provides audible and visual generator information to alert the staff to maintenance needs.

Indicator Function Level 1 Level 2
Panel Shutdown Remote Panel Shutdown Remote
Overcrank X X X X X O
Low Water Temp X NA X X NA O
High Engine Temp (Pre-Alarm) X NA X O NA NA
High Engine Temp X X X X X O
Low Oil Pressure X X X X X O
Overspeed X X X X X O
Low Fuel X NA X O NA O
Low Coolant X O X X O X
Generator Supplying Load X NA NA O NA NA
High Battery Voltage X NA NA O NA NA
Low Cranking Voltage X NA X O NA O
Low Battery Voltage X NA NA O NA NA
Battery Charger AC Failure X NA NA O NA NA
Not In Auto X NA X X NA X
Lamp Test X NA NA X NA NA
Audible Alarm Silence NA NA X NA NA O
Remote Emergency Stop NA X NA NA X NA
Notes: (1) All panel pre-alarms and alarms are visual and audible. The main control panel is located on the generator set in WINCO applications. (2) Shutdowns will immediately stop the generator to prevent damage to the generator set and to the facility. (3) All remote alarms and pre-alarms are audible and visible through the remote annunciator panel. (4) X-Required, O-Optional, NA-Not applicable.




























Automatic Transfer Switch (ATS): WINCO uses ASCO transfer switches for NFPA 110 applications. It is essential that a high quality switch with adequate withstand ratings is used to ensure that a safe and effective transfer to the emergency generator is accomplished. It is important to remember that the initial load can be substantial because all of the facility's loads are attempting to start simultaneously. The ASCO Series 300 switches are designed to meet all applicable standards and have adjustable time delays that allow flexibility for each unique application. The transfer switch will exercise the system on a weekly basis. Exercise cycles generally last for 20-30 minutes.

Acceptance Tests: Before a Level 1 emergency generator installation is accepted the generator set must be tested on site. When bidding the job it should be clear who is responsible for the acceptance tests and who will pay for the fuel consumed during testing. The following outline is not intended to be all-inclusive and a copy of the most recent publication of NFPA 110 should be obtained for complete details. 

  • A simulated power failure is created by shutting off the utility supply breaker to at least one transfer switch and applying the intended load or a simulated load equal to the intended load. The time it takes to start, reach operating speed, reach steady state after accepting load, retransfer delay, and cooldown are recorded. The load will be applied for at least 1.5 hours and performance parameters are logged.
  • A full load test is performed for two hours at full nameplate load minus applicable derating factors. A load of at least 30% is applied for 30 minutes after which a load of at least 50% is applied for an additional 30 minutes. The final 60 minutes are at 100% load. Performance parameters are recorded every 15 minutes throughout the duration of the test.
  • The generator is run through one complete cycle crank test and is observed. The generator is normally prevented from starting by interrupting the fuel supply.
  • After the cycle crank is completed the battery charge rate is recorded at 5 minute intervals until the rate stabilizes or for at least 15 minutes.

The authority having jurisdiction should be informed of the tests so that they are able to witness the assessment.

Maintenance: The maintenance requirements for NFPA 110 machines are extensive and designed to ensure the equipment is always in working order. Before quoting maintenance contracts for this type of equipment it is essential to understand the requirements. The most recent copy of the NFPA 110 will provide complete maintenance standards. It is required that maintenance and exercise periods are recorded in a log that is readily available. The most recent NFPA 110 publication should be consulted for the frequency of the required tests.