How short circuits occurs?
A short circuit usually occurs when the insulation between wires breaks down and they become accidentally connected together.
Short circuits cause extreme amounts of electrical and mechanical stresses on equipment. Equipment that will regularly carry 100amps of current can be exposed to thousands of amps of current. transformers explode, lines vaporize, poles start on fire, etc. if short circuits are not removed as soon as practical.
To avoid any short circuit in a house we suppose to have electrical panel with proper size of circuit breakers. These breakers installed to feed a number of circuits in the house which is controlled by the Electrical Code. The breaker ampacity is depend on the load size (light circuits, outlets, microwave, dryer, furnace, cenral vacuum). The individual circuits are calculated depend on the size of the load (like motors, transformers sucking a lot more…