By Maj (r) Muhammad Ali
Lahore: A short circuit is an abnormally low resistance circuit, allowing massive current flow, which overheats the electric wire. It is assumed to cause electrical fires. This assumption, however, is incorrect. An electrical circuit consists of a power source, a rotection device like a fuse and circuit breaker, wiring and load.
Electric wires are often wrongly blamed for electrical fire. Whenever there is an excessive flow of current, the circuit breaker, if designed correctly, must trip off and save the circuit thus avoiding the possibility of fire. An electrical fire only breaks out when the entire system has design faults: low quality wiring, circuit breaker of incorrect amperage, and sub-standard circuit breaker mechanism.
Sub-standard wires are sold under fake names of high quality brands. It is difficult for the architect/designer to verify the quality of the cable. The copper used for such spurious cable is of low conductivity, heating the cable. This, in turn, melts the insulation, which is again of low quality, leading to short circuiting.
The circuit breaker must trip off to avoid disaster in case of short-circuiting. Circuit breakers available locally are usually not of standard quality and do not trip off.
Electrical fires usually break out because of faulty circuit breakers. There are again no means to verify the quality of the breakers by the field staff supervising construction.
Quality control at the construction site is an expensive and laborious job. Sample test of cable and circuit breakers should be conducted after delivery at site. Branding alone does not help.
The cable and circuit breaker conforming to BSS should be specified by the designers and architects after delivery and checked accordingly. Brand myth should be avoided. Bilal Ganj in Lahore is littered with spurious manufactures. They, in collaboration with the contractors, are causing a colossal loss at national level in addition to sporadic disaster to buildings and installations. Invisible loss in the form of power wastage goes unnoticed.
Source: Daily Times