The NETA “Maintenance Testing Specifications for Electrical Power Distribution Equipment and Systems”1 2005 Edition is an excellent source of information for performing the required maintenance and testing of these devices. Visit the NETA website (http://www.netaworld. org) for further information.
Because of the electrical hazards to which they may be exposed, all workers involved in electrical testing and maintenance must be qualified personnel as defined in the OSHA and NFPA standards. NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, states that equipment deterioration is normal, but equipment failure is not inevitable.
Normal deterioration begins as soon as new equipment is installed and if unchecked can eventually cause equipment failure. Deterioration can be accelerated by factors such as environment, overload, or
severe duty cycles.
A periodic maintenance program can identify these factors and provide measures for coping with them. There are other potential causes of equipment failure that can also be detected and corrected.
Among these are load changes or additions, circuit alterations, improperly set or improperly selected protective devices, and changing voltage conditions. Without an effective periodic maintenance and testing program, management assumes a greatly increased risk of a serious electrical failure and its consequences.
An effective electrical preventive maintenance program can reduce accidents, save lives, and minimize
costly breakdowns and unplanned shutdowns of production equipment. Failures can be averted by identifying and correcting impending troubles before they become major problems requiring more expensive, time consuming solutions.
The relationship between safety and preventive maintenance is not a difficult one to establish. Properly designed equipment that is properly installed is well capable of doing its job when it is new. As equipment ages however, several factors begin to take their toll on electrical equipment.
● Dust, dirt, and other contaminants collect on equipment causing the equipment to overheat and bearings and other moving parts to bind.
● Vibration causes hardware to loosen. Subsequent operations of equipment can cause joints and equipment to fail explosively.
● Heat and age can cause insulation to fail, resulting in shock hazards to personnel.
● Increased loads, motor starting surges, and power quality issues such as harmonics combine to increase the aging process and set the stage for equipment failure.
Unfortunately, the ultimate failure of unmaintained equipment usually occurs when the equipment is needed the most—during electrical faults. Such failures result in arc and blast events that can and do harm workers in the area.
They also result in significant downtime, loss of equipment, and construction cost incurred in rebuilding the equipment. The only way to ensure that electrical equipment continues to operate in an optimal manner is to maintain it so that it stays in factory-new-operating condition.