Final answer:
Contact between a foreign conductor and a live wire can cause electric shock and thermal hazards, potentially leading to appliance damage, fires, or electric shocks. Safety measures like grounding and circuit breakers help prevent these risks.
Step-by-step explanation:
When a foreign conductor comes into contact with a wire carrying current to an appliance, it can lead to a variety of dangerous outcomes, including electric shock and thermal hazards. If the foreign conductor has significantly different electrical properties, such as resistance, it can disrupt the circuit's functioning. This can cause an increase in the current (I) flowing through the wire, leading to overheating as per the formula P = I²Rw, where Rw represents the resistance of the wires. Overheating can damage both the conductor and the appliance, potentially leading to fires, melting of components, or failure of the device.
Furthermore, the risk of shock is prevalent, especially if the insulation on wires is worn and contact is made with a conductive case of an appliance that is not properly grounded. This can result in a dangerous situation where the circuit may not trip, exposing individuals to the risk of severe electric shocks. Proper grounding and the use of safety devices such as fuses and circuit breakers are essential to prevent such hazards.