Final answer:
The assembly mentioned is a power distribution unit for controlling and supplying power to mobile setups and temporary equipment. It includes components like circuit breakers, receptacles, and GFCIs to manage electricity flow and prevent hazards. Circuit breakers and GFCIs specifically interrupt excessive currents and guard against electric shocks.
Step-by-step explanation:
The assembly described in the question is a power distribution unit designed to safely supply and control electrical power for mobile homes, recreational vehicles, park trailers, boats, or temporary equipment. They typically feature a combination of receptacles, circuit breakers, fuseholders, buses, and watt-hour meter mounting means. These components work together to manage the flow of electricity and protect against excessive currents that can cause thermal hazards.
Circuit breakers and fuses are safety devices that act as automatic switches, opening to interrupt current when it exceeds safe levels. Fuses melt and need replacement when triggered, whereas circuit breakers can just be reset. Ground fault circuit interrupters (GFCIs) quickly respond to changes in current, particularly in situations where there is a difference in the current entering and leaving a circuit, which could indicate a leakage often associated with electric shock. This makes GFCIs especially valuable in areas with high moisture like bathrooms and kitchens.
The power distribution units utilize a three-wire system with live/hot, neutral, and earth/ground wires; the appliance's neutral wire and case are grounded, which helps to protect against both thermal and shock hazards. Isolation transformers and ground fault interrupters (GFIs) are examples of devices using induction to prevent shock by detecting unintended paths for current flow or by insulating the device from the power source.