During the 2003 Blackout in the Northeast, reports indicate that 20% of the generators either failed to start or failed shortly after starting. The number one cause of the generator system failures was dead or weak batteries. Other causes were old or contaminated fuel, corroded cables, clogged radiators, deteriorated belts and hoses, and control panel circuit board and sensor failures.
While planned maintenance will not guarantee that you will never have a problem – routine inspections and testing enable us to find minor problems and correct them before they become major problems.
NFPA 110, Standard for Emergency and Standby Power Supply Systems (EPSS) covers performance requirements for power systems providing an alternate source of electrical power in the event the primary power source fails. The standard addresses installation, maintenance, operation, and testing requirements for generators and automatic transfer switches (ATS).
NFPA 110 stipulates several different site tests for compliance. The following are some highlights from NFPA 110 for the maintenance and testing of emergency and standby power systems:
- Emergency power sources (i.e. the generator set) are to be tested every month with available system loads.
- Diesel generator sets shall be tested monthly at not less than 30 percent of the rating. If 30 percent of the nameplate rating cannot be achieved with the available system loads, a load bank test shall be performed annually at 25 percent of the nameplate rating for 30 minutes, followed by 50 percent load for 30 minutes, followed by 75 percent load for 60 minutes for a total of two hours of continuous operation.
- Transfer switches and paralleling switchgear shall be subject to inspection, testing, and a maintenance program. Transfer switches shall be operated monthly. Maintenance programs for transfer switches include checking of connections, inspection or testing for evidence of overheating and excessive contact erosion, removal of dust and dirt, and replacement of contacts when required. An annual maintenance program including one major maintenance and three quarterly inspections is recommended. The major maintenance includes a thermographic infrared scan or temperature scan of the ATS.
- For Level 1 generator sets (i.e. where the failure could result in the loss of human life or serious injury), the main and feeder circuit breakers between the generator set and the transfer switch loads are to be exercised annually with the generator in the “off” position. Additionally, the main and feeder breakers in excess of 600 volts are to be exercised every six months and are to be tested under simulated overload conditions every two years. Further, a Level 1 EPSS shall be tested for at least four-hours, at least once every 36 months.
- Main feeder insulation resistance tests shall be performed during acceptance and repeated whenever damage is suspected.
- Lead acid batteries in the system shall be tested monthly for specific gravity and defective batteries shall be replaced immediately.
- Written records of all inspections and testing are to be maintained and available for inspection in the on-site maintenance log.
In addition to NFPA 110, the Joint Commission, which accredits and certifies healthcare organizations, recommends that all automatic transfer switches are tested 12 times per year at 20 and 40 day intervals. The monthly test consists of electrically operating the transfer switch from the standard position to the alternate position and then a return to the standard position. Additionally, the Joint Commission requires that a written emergency plan be in place with clearly defined responsibilities and assignation of adequate staff, including multiple backup personnel. All such persons must be trained. The Joint Commission maintenance requirements must conform to NFPA 110 for testing purposes, but in addition the Elements of Performance also call for monthly testing of generator and automatic transfer switches, as well as, a four-hour test of the EPSS at least once every 36 months.
Whether your facility is legally required to comply with NFPA 110 or you just want adopt the best practices in the industry for maintaining, operating and testing your emergency and standby power systems, Curtis Power Solutions can help you meet these requirements by providing:
- Assistance with establishing and refining your emergency contingency plans
- Maintenance contracts for your emergency power supply system equipment,
- EPSS testing programs that include load bank testing, ATS and electrical system testing, and fuel system testing and cleaning with certified records and reports.
- Competency training and testing for your maintenance personnel and operators
- Infrastructure planning recommendations to incorporate mobile generator sets during extended outages or for additional redundancy.
- New equipment or equipment replacement
For more information about NFPA 110 or Joint Commission requirements, please visit those sections of our website, download our Emergency Power System Maintenance Best Practices presentation, or Contact Us. We have also put together a collection of maintenance and testing schedules, forms and logs to help keep you in compliance with NFPA 110 recordkeeping rules.