Final answer:
A three-phase, four-wire system supplies voltage and current from power lines for residential and commercial use, with elaborate safety measures designed to protect against electrical hazards, including the use of circuit breakers, fuses, and GFCIs.
Step-by-step explanation:
A three-phase, four-wire system can provide power to several different types of loads. This type of electrical system is designed to supply voltage and current from power lines for use in homes, businesses, and other settings. The system typically comprises three live/hot wires and one neutral wire, which is grounded.
This setup allows for both single-phase and three-phase equipment to be powered. Comprehensive safety measures are incorporated to prevent shocks and thermal hazards, most notably through the use of a circuit breaker or a fuse to interrupt any excessive currents. Another safety feature is the ground fault circuit interrupter (GFCI), which protects against electric shock by quickly shutting off the power if a loss of current to unintentional paths is detected.
In the context of electrical safety, the three-wire system ensures that the neutral wire is grounded, creating a zero voltage reference and a safe return path for the current through the earth. Additionally, the grounding of the appliance case minimizes the risk of shock hazards. Isolation transformers and devices like GFCIs and circuit breakers are some of the safety systems that use principles of induction in their operation to protect against electrical hazards.