Select the rating of the fuse, keeping in view the standards of fuse rating manufactured by manufacturers, to protect a resistive circuit having 18 A full load current.
Multi Line Text.
Without a direct short, it is feasible for the circuit current to rise. When the value of a resistor, capacitor, or inductor varies, so does the overall circuit impedance. When the ohmic value of a resistor falls, so does the overall circuit resistance. The capacitive reactance of a capacitor diminishes when there is dielectric leakage. Inductive reactance drops when an inductor's winding is partially shorted. Any of these circumstances will increase circuit current. Because the wiring and components of the circuit are intended to tolerate regular circuit current, an increase in current would result in overheating (just as in the case of a direct short).
The heat created by the increased current causes most difficulties connected with a direct short or excessive current. Excessive heat causes damage to circuit components, the threat of a fire, and the release of harmful gases from electrical components. High heat can arise in the absence of a direct short or excessive current. If a motor or generator's bearings fail, the motor or generator will overheat. Excessive heat would be a concern if the temperature around an electrical or electronic circuit rose (due to the failure of a cooling system, for example).