Don’t Neglect Electrical Equipment Maintenance
Maintenance Technology | May 10, 2017
Electrical equipment that is not properly maintained is not NFPA 70E compliant and, therefore, dangerous to personnel and business operations.
By James Godfrey, CESCP, Craft Electric & Maintenance
Since the release of the 2015 edition of NFPA 70E, “Standard for Electrical Safety in the Workplace,” there seems to be a tremendous push by companies to achieve compliance, and rightfully so. As noted in this standard, more than 2,000 people each year are admitted to burn centers with severe arc-flash burns.
NFPA 70E states that an arc-flash risk assessment shall be performed and shall determine if an arc-flash hazard exists. Arc flash is the result of an arcing fault that bridges the air gap between conductors such as phase to phase, phase to neutral, or phase to ground. In an article published in Safety and Health Magazine (August 2009) the most common cause of arc-flash accidents is human error. However, such things as the accumulation of conductive dust inside an enclosure and equipment failure, most likely the result of inadequate maintenance, can also cause these arc-flash events. In short, if electrical-equipment maintenance is neglected, something is going to blow. When that happens, it can be catastrophic.
OSHA CFR 1910.303(b)(1) states that electrical equipment shall be free from recognized hazards that are likely to cause death or serious physical harm to employees. Simply put, condition of maintenance must be considered. NFPA 70E states that electrical equipment shall be maintained in accordance with manufacturer instructions or industry-consensus standards to reduce the risk associated with failure.
The term “industry-consensus standards,” typically refers to a standard that has been accepted as recommended practice such as NFPA 70B, “Recommended Practice for Electrical Equipment Maintenance.” This standard addresses such things as development and implementation of an electrical preventive-maintenance (EPM) program, recommended intervals for maintenance, testing and test methods, reliability-centered maintenance (RCM), and acceptance testing.
When having an arc-flash risk assessment performed and not addressing the maintenance component of an electrical safety program, some assumptions must be made. These include, but are not limited to, equipment that is operating properly, equipment that has been properly maintained, and condition of maintenance, as well as opening times of over-current protective devices.
NFPA 70E states that over-current protective devices that have not been properly maintained can cause increased opening times, thus increasing the incident energy in the event of a fault in the electrical-distribution system. This creates a major safety concern for personnel and their interaction with energized electrical equipment, as well as lost revenue due to equipment failure. As a result, careful consideration must be given to the development and implementation of an effective electrical-safety program to maximize benefit and minimize cost. The arc-flash risk assessment can be a costly endeavor and the results obtained can be misleading or inaccurate because of improper or inadequate maintenance.
Surprisingly, a high percentage of facilities are not OSHA and NFPA compliant and have little knowledge of what it takes to be compliant in the area of electrical safety. Furthermore, some are doing very little in terms of electrical-equipment maintenance and are satisfied with having infrared scans done on the electrical panels because it has been recommended by their insurance company. Infrared thermography is very effective at identifying heat-related issues, but does not satisfy the requirement to maintain electrical equipment in accordance with manufacturer instructions or industry-consensus standards.
Infrared technology generally requires a direct line of sight to the target area, which raises another safety concern. Pursuant to the NFPA 70E requirements, the level of risk must be assessed before removing equipment covers and exposing energized conductors and circuit parts. To properly assess the risk, such things as available fault current and opening times of over-current protective devices must be considered.
Available fault current is the amount of current that may be present at any point in the electrical system as a result of a short or fault condition. If a fault were to occur in the electrical system as a result of equipment failure or human error, the equipment affected may not be rated to handle the fault current and this could be catastrophic. If an arc-flash risk assessment has been performed, then the amount of incident energy (typically expressed in calories/cm2) must be observed and personal-protective equipment selected and put on before removing equipment covers.
At this point, a decision must be made, based on personnel risk, to open or not open equipment and expose energized conductors and circuit parts. If it is determined that removing equipment covers could expose personnel to an unacceptable risk, the equipment should be de-energized before performing any type of preventive maintenance. An infrared scan would be ineffective in this case.
An effective preventive- and proactive-maintenance program should take into consideration safety, the age of the equipment, operating environment, and the criticality of the asset. If infrared scanning is the only form of preventive-maintenance approach that’s been employed, equipment reliability and safety have been compromised. That type of situation should be of great concern to plant managers, maintenance managers, technicians, and other employees.
As outlined in NFPA 70B, several available maintenance and testing options are specific to the targeted equipment. Take, for example, low-voltage service-entrance equipment, often referred to as switchgear. Some of the maintenance recommendations outlined in NFPA 70B include energized/de-energized inspection and de-energized cleaning. While the equipment is in a de-energized state, all bolted connections and cable terminations should be torqued, in accordance with manufacturer specifications.
During de-energized maintenance, molded-case/insulated case circuit breakers should be exercised manually to keep the contacts clean and help the lubrication perform properly. This simple maintenance procedure is often overlooked, and breaker failure is a common result. In addition, breaker testing (primary and secondary injection) and protective relay testing are also recommended. These and other factors must be considered when determining what compliance means and developing an electrical-safety program that satisfies the OSHA and NFPA requirements.
We’ve heard that, “an ounce of prevention is worth a pound of cure.” This phrase should have significant meaning when management is struggling with how to comply with the latest regulations imposed by OSHA as it relates to safety in the workplace.
Among the several elements that make up an effective electrical-safety program, electrical-equipment maintenance is one that cannot be ignored. When the decision is made to have an arc-flash risk assessment performed, consider the condition of maintenance of the electrical equipment and the affect it will have on the results of the risk assessment. This will ensure that employees stay safe and assure management that money appropriated is well utilized. The result of a well-administered electrical-safety program will reduce life-safety risk, cut business interruptions, and extend the life of electrical equipment. MT
Jay Godfrey, CESCP, has more than 25 years of experience in the electrical-contracting industry and is a licensed electrical contractor in Georgia. Godfrey is OSHA trained, NFPA certified and, for the past eight years, has been working as a preventive-maintenance and electrical-safety consultant with Craft Electric & Maintenance, Atlanta.