ElectricalPreventiveMaintenance
Protecting Equipment, Workers,and the Bottom Line
By Diane M. Calabrese
While it is possible to design and specifyreliability and maintainability into electricalsystems, without an effectiveelectrical preventive maintenance (EPM) program,electrical systems will fail. This can resultfrom normal equipment deterioration, changesin environmental conditions, lack of equipmentexercise, installation deficiencies not identifiedduring commissioning, factory defects, orchanges in functional system operations.
“Without planned maintenance, building owners assume a greater risk of electrical-system failures, explosions, and fires, which can lead to property damage, injury, loss of production, and costly repairs,” says Roy Rockvam of Parsons Technical Services.
Recent estimates approximate losses from outages or other electrical mishaps at between $30 billion and $200 billion, a staggering sum even at the range’s low end.
So how are costly electrical-system failures, shutdowns, and repairs avoided? Ensure EPM is regularly scheduled and performed. Simply stated, every business, no matter its size or critical function, should have an EPM program in place, says Rockvam. It’s no different than taking a car in for an oil change or tire rotation.
Identifying Potential Hazards
A well-administered EPM program can reduce accidents, save lives, and minimize costly breakdowns and unplanned shutdowns of production equipment. Impending problems are identifiable — and solutions are applied — before they develop into more expensive, time-consuming problems. Refer to NFPA 70B, “Recommended Practices for Electrical Equipment Maintenance,” 2002 edition.
EPM focuses on identifying potentially hazardous areas. Some of these may seem insignificant at first glance, but they could lead to disastrous events. “In low-voltage settings, for example, overcurrent protective devices [circuit breakers] require the most conscientious attention,” says Rockvam. “Circuit breakers that are not initially tested or properly maintained, for instance, have a failure rate of one in eight during a five-year period.”
In typical, low-voltage office settings (120 to 600 volts), EPM discovers problems that differ somewhat from high-voltage environments (more than 600 volts). For example, overloading, code violations, loose connections caused by thermal expansion and contraction, destructive harmonics, and trash accumulation around components often occur in low-voltage workplaces. Stress-cone failure, voltage corona, and loose connections, as well as dirt and contamination issues, often crop up in highvoltage settings.
The consequences of ignoring problems in either case are often dire. According to the Institute of Electrical and Electronics Engineers (IEEE), poorly maintained electrical systems fail three times more often than systems receiving preventive maintenance. In other words, no matter what type of electrical equipment is operating, it needs an EPM program. “Whether a component is linked to the grid or derives its power from a diesel generator, it belongs under an EPM umbrella,” says Rockvam.
Performing Regular Checkups
The fundamental concept of EPM is to keep it clean, dry, and tight. This means checking equipment for deterioration, exercising mechanisms to ensure proper function, cleaning and tightening all connections, and keeping equipment enclosures free of dirt and debris. In other words, EPM involves regular inspection, testing, and maintenance of electrical components. An EPM program’s success depends on a number of critical factors:
• Concurrently maintainable electrical systems
• Having qualified personnel perform the work
• Conducting inspections regularly
• Making informed decisions when correcting problem conditions
• Performing the work in a timely manner
• Keeping meticulous records
EPM Worker Guidelines
Individuals who conduct EPM analyses should have proper training to work on the specific equipment that is tested or maintained. This means they must understand how the equipment functions electrically and mechanically. Working on high-voltage equipment and protective relay devices often requires special training.
Every EPM worker must also thoroughly understand safety practices and procedures. For example, any individual performing EPM should have CPR (cardiopulmonary resuscitation) training and know the procedures for locating and operating emergency shutdowns and power disconnects. Workers must also follow basic safety practices, such as using personal protective equipment and performing work carefully in a timely manner while following written procedures for every action.
The most fundamental safety procedure when dealing with electrical components is to assume they are “hot,” or “live,” until otherwise verified. Whenever possible, before any EPM begins, it is highly recommended to de-energize the piece of equipment for an added level of safety. EPM practices focus on protecting both EPM and non-EPM workers alike — and for good reason. “A safe work environment is priceless,” says Rockvam. “That’s the first and foremost goal of any EPM program.”
Function and Structure Dictate Frequency
EPM frequency depends on environmental conditions and the importance of the equipment, as well as loading and use. Mission-critical facilities, such as data centers, hospitals, and radio stations, require ongoing EPM, while other facilities, such as office buildings, may only require annual or biannual EPM. The type of building structure is not as critical as the function it serves and its importance to the survival of its owner, occupants, and customer base.
NFPA 70B provides initial guideline maintenance intervals for various pieces of electrical equipment. Typical programs involve complete visual inspections and thermographic imaging of electrical and major mechanical equipment as well as cleaning and functional operation of electrical equipment wherever possible to verify proper system operation.
Prior to acceptance and operation, new equipment should undergo performance testing and commissioning. Additional performance testing should be completed at intervals recommended in NFPA 70B as well as during the equipment manufacturer’s planned maintenance based on equipment age and usage.
Evaluating Results, Implementing Corrections
Facilities management/owners must take action to correct deficiencies identified during routine inspections, thermographic surveys, testing, and commissioning. Proper and timely resolution to identified problems will assure system reliability and decreased cost of repairs, as well as guard against unplanned shutdowns, loss of production, etc.
Why Keep Records?
Clear record keeping keeps an EPM program cost-effective because it ensures all work is performed on time, and tracking test findings over time often leads to preemptive action that prevents future equipment failures. Typically, manufacturers provide guidelines for routine maintenance on their equipment. Following those protocols to the letter, including keeping a record of what maintenance procedures were performed and when, is the best place to start, says Rockvam.
EPM: Not Why, but Why Not?
EPM programs benefit companies in many ways. First, repairing equipment before it fails protects other sensitive components, like circuit breakers and relays, from damage. Second, replacing failed equipment with new components rather than repairing or maintaining existing ones often raises compatibility issues that require costly modifications. Third, replacing failed equipment is not always quick or easy, which adds to downtime and negative financial impact. Finally, making emergency repairs racks up much higher bills than normal maintenance.
EPM programs also increase equipment efficiency and reduce utility bills. Just cleaning and tightening electrical connections alone can lower energy costs. With oil prices hitting $60 and higher, every bit of energy efficiency translates into significant savings.
Perhaps the greatest gain from implementing EPM, however, is increasing system reliability and reducing equipment failures. According to the IEEE, EPM can cut the likelihood of unexpected outages by two-thirds. EPM also lowers the risk of sparks and flames.
All of this points to EPM as one of the soundest investments a company can make. To put it simply, the adage, “if it ain’t broke, don’t fix it,” does not apply to electrical components.
For more information on EPM, visit the National Fire Protection Association’s Web site at www. nfpa.org or the IEEE Web site at www.ieee.org. Both organizations offer help in initiating EPM programs. The Occupational Safety and Health Administration provides competence guidelines for EPM workers. For more information, visit www.osha.gov/SLTC/electrical.
