Why Electrical Equipment Maintenance is Important?
This blog offers a comprehensive insight into the maintenance requirements for protective, overcurrent devices and the probable impact on the arc flash incident energy when maintenance isn’t carried out properly. Electrical testing and preventive maintenance are one of the fundamental functions to be performed for maintaining the integrity and reliability of electrical distribution systems, along with the protection of personnel and equipment. However, preventive maintenance of electrical equipment and systems, particularly with respect to overcurrent protective devices is usually overlooked or is performed inadequately or infrequently. Due to a sticky operating mechanism, an unintentional time delay in the operation of a circuit breaker may cause the arc flash’s incident energy to rise, often drastically.
The overcurrent protection for equipment and conductors is offered to open the circuit if the current approaches a value that will cause a dangerous or excessive temperature in conductor insulation or conductors. With respect to circuit breakers, the only way to achieve this is through proper testing and maintenance of these devices based on the instructions of the manufacturer.
Testing and Maintenance Considerations
This blog will not address particular testing and maintenance procedures. However, there are two important steps that must be taken into consideration when taking into account the testing and maintenance requirements for overcurrent protective devices.
- The first step in appropriately maintaining overcurrent protective devices and electrical component is to understand the recommendations and requirements for electrical equipment maintenance from various sources.
- The subsequent step is to offer sufficient qualification and training for employees. Employees who perform maintenance on electrical installations and equipment shall be qualified persons and shall be familiar with and trained in the specific tests and maintenance procedures required.
Arc Flash Hazard Considerations
Testing and maintenance are mandatory to ensure proper safety of personnel and protection of equipment. With respect to personnel protection, NFPA 70E entails an arc flash risk assessment to be carried out before anyone reaches circuit parts that haven’t been placed in an electrically safe work condition or energised, exposed electrical conductors. According to the 130.5 of NFPA 70E, the opening time of the overcurrent protective device, its condition of maintenance, and its design must be taken into consideration by the arc flash risk assessment.
Every calculation for identifying the incident energy of an arc flash entails the arc clearing time of the overcurrent protective device. This clearing time is derived from the time-current curves and device settings. This information may also be acquired from an existing engineering protective device coordination study, which is established on what the protective devices are expected to do. If, for instance, a low-voltage power circuit breaker hasn’t been maintained or operated for many years and the lubrication had become hardened or sticky, the circuit breaker could take a number of additional minutes, seconds, cycles, or longer to get rid of a fault condition. This time delay, though unintentional, may have catastrophic consequences because of the incident energy, if an arc flash occurs.
If an unintentional time delay occurs, and the worker is protected based on what the circuit breaker is required to do, the worker could be killed or seriously injured because he/she was under-protected. The importance of maintenance in an electrical safety program cannot be overemphasised. Maintenance must be carried out based on the industry consensus standard or instructions of the manufacturer for minimising the risk of having an unintentional time delay in the operation of the circuit protective devices.
To protect personnel and electrical equipment, it’s important to perform appropriate electrical equipment preventive maintenance. The industry consensus standards or the instructions of the manufacturer exist to facilitate users with the testing and maintenance of electrical equipment. When the overcurrent protective devices are properly tested and maintained for appropriate operation and adjustments, arc flash hazards and equipment damage may be restricted as expected. Unluckily, a lot of people in the industry think that only because the machines are running or the lights are on that maintenance isn’t needed, and everything is okay because the circuit breaker is not at fault. No, the circuit breaker we closed, it isn’t working. Working is when a short-circuit, ground-fault or overload occurs and the circuit breaker automatically opens in the specified time, or closed, or manually opened. It is important to maintain the overcurrent protective devices to ensure that the electrical systems and equipment remain reliable. It also ensures that the personnel are safe.
If you’re on the lookout for an electrical maintenance engineer, Night Owl Electrical Controls is always there to assist you.