As we promised in our last installment, we will continue the discussion on equipment failure.  We will continue to dive into various electrical components and how they work, their longevity, usage, and testing. 

Transformers

Transformers are large scaled pieces of equipment that are used to either reduce or increase the voltage produced by a current.  Liquid filled transformers are most often installed outdoors on a concrete slab, under a canopy to protect against the elements.  The liquid serves two purposes, it cools the transformer coils and provides insulation between the coils and the grounded tank. 

Older transformers use insulating mineral oils where as newer transformers use either a silicon based, fluorinated hydrocarbon, or combustion resistant vegetable oil based dielectric fluid or synthetic esters.  These insulating fluids break down first due to the entrance of moisture, impurities, and intermittent periods of heating and cooling.  Liquid transformers can deliver consistent service for more than 30 years with regular maintenance, fluid replacement, testing, and repairs.

Low Voltage Circuit Breakers

LV distribution systems commonly use molded case circuit breakers.  These systems contain two elements that deteriorate when used, a spring-loaded operating mechanism and copper contacts.  These two components will wear out from abrasion while closing and arching when the breaker is opened.  Larger breakers can be replaced. 

As these systems age the mechanisms that operate will start to slow down which delays clearing times.  The springs operating the mechanism are strong and hardly ever need to be fixed or repaired.  Lubrication however will deteriorate and need to be replenished to avoid the slower clearing times.  When a breaker operates above the normal trip rate it should be replaced.  These systems often last upwards of 20 years.  After 20 years replacement is most often recommended whether or not you are seeing slower clearing times during testing.

Low Voltage and Medium Voltage Cables

For most of us cables are quiet simple consisting of a stranded aluminum or copper conductor that is wrapped in insulation as well as a jacket that is resilient to the weather.  The manufacturing of electrical power and control cables sounds fairly simple however this industry is one that is in fact highly specialized.

Assessing the integrity of electrical cabling and its remaining longevity is important however can be quite complicated.  Cables can quickly lose electrical integrity while it is in use because of air pockets, gas pockets, and the voids found in the insulation.  This occurs due to thermal expansion and contraction.  If cables are in water their deterioration will occur at a faster rate.  Testing and analysis on these voids will offer up an estimate on the life that remains for the cable. J & P Electrical Company is a full-service electrical company that supplies contractors, end users, and supply houses with new surplus, quality reconditioned, and obsolete electrical equipment. We purchase a wide range of electrical equipment such as bus plugs, bud ducts, panel switches, substations, and transformers.  More information can be found at https://www.jpelectricalcompany.com



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