Describe how the third wire of the threewire power cord acts

Describe how the third wire of the three-wire power cord acts as a protective mechanism against electric shock hazards. Describe the difference between fuses and circuit breakers. Where might each type of device find its bost use?

Solution

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Both the fuse and the circuit breaker (CB) are intended to open a circuit for excessive current.

fuse is a small glass or plastic tube that contains a piece of wire. That wire is carefully calibrated so that it will only allow a certain level of current to pass through it. Any more, and the wire will melt from the heat, breaking the circuit. This means that if a power surge comes into your home, a circuit will be broken before it causes damage to your appliances.(CB) are intended to open a circuit for excessive current.

Circuit breakers are usually more costly and larger than fuses. Fuses are more likely to be abused because if blown and the user wants to return the equipment to operation AND there is not a spare fuse then he will substitute a fuse of higher value or short out the fuseholder in frustration and defeat the saftey of the fuse.