Statistics indicate that more fires start from electrical system failure than from any other cause. Electrical equipment is usually well designed and properly installed. However, the principal reason for electrical system breakdown is the failure to maintain the installation in its designed state.
As soon as electrical equipment is installed, normal deterioration begins. If left unchecked, the deterioration process can cause malfunction or complete failure. Performance and life expectancy of the equipment are decreased by factors such as environmental conditions, system overload or excessive duty cycles on equipment. As a way to frame a basic electrical maintenance program, the fundamentals are a good place to start.
Fundamentals of Electrical Preventive Maintenance
Fundamental efforts must first be directed toward initiating an effective electrical preventive maintenance program to reduce the potential for a serious electrical interruption. The basic rule applying to all electrical apparatus is to keep it clean, keep it dry, keep it tight, and prevent friction.
Dirt is a common cause of electrical failure. Dirt is the day-to-day accumulation of particulate matter from the atmosphere consisting of dust, lint, chemical, metallic particles, oil mists, spray residues, etc. if allowed to accumulate, it can contaminate electrical equipment causing overheating and increased electrical resistance. In some applications heavy contamination cannot be avoided. This is typical of foundries, mills, quarries, cement plants, grain elevators, etc. in these applications, special apparatus designs are appropriate. Every effort, however, should be made to keep equipment free to particulate matter. This includes activities such as weekly cleaning of motor casings and keeping electrical cabinets free of dust by vacuuming. Every maintenance opportunity should include a thorough cleaning of apparatus.
Electrical equipment operates best in dry and corrosive-free atmospheres. Humidity accelerates the oxidation of metals used in the electrical gear. Oxide build-up increases resistance thus reducing effective contact and the resulting heat can lead to eventual failure. High moisture levels can lead to direct short circuiting and immediate failure. Humidity should be controlled if possible and guarded against by using equipment designed for use in damp or wet conditions. Some typical example of high moisture areas or where there is an exposure to moisture or corrosion included: dairies, mills, canneries, tanneries, meat packing plants, locations of high humidity, metal plating, and areas where acids and alkali chemicals are used, handled or stored.
Many electrical components operate with high speed movement while other electrical equipment may not move at all. Motion of operating equipment will eventually cause wear and imbalance. Appreciable imbalance tends to create vibrations in equipment and loosen vital connecting parts. Routine maintenance is necessary to detect wear and loosening of parts and connections. This should include a check for tightness of accessible hardware and bolted parts as a simple precautionary measure. Tightening a screw or connection can only take but a moment. It can prevent hours of searching for intermittent trouble.
Electrical equipment that is operating properly has minimum of friction, however, there is always the potential for mechanical breakdown as a result of increased friction. Friction can result from numerous causes. Some of the most common reasons include misalignment of equipment, excessive wear and the failure to properly lubricate. Some electrical apparatus does not require lubrication nor should it be performed unless specified by the manufacturer. Over-lubrication is a dangerous practice because excessive oil can collect dust and abrasive materials and even oxidize into difficult to remove deposits on the machinery. Lack of required lubrication will significantly add to overheating of the unit and may eventually lead to failure. Machinery must be properly lubricated at recommended frequencies. Alignment of machinery components is critical to help reduce friction. The key element ismaintenance