Final answer:
Circuit breakers indicate whether they are open or closed and are essential for electrical safety, preventing thermal overload and safeguarding against electrical shocks. They are resettable components unlike fuses and are a standard part of modern electrical systems.
Step-by-step explanation:
All circuit breakers must clearly indicate whether they are in the open (OFF) or closed (ON) position. Circuit breakers are critical safety features in electrical systems, preventing thermal overload by automatically opening when sustained current exceeds safe limits. They are designed to be reset, unlike fuses which need to be replaced after they are blown due to an excessive current. The presence of a circuit breaker or fuse is standard in modern household and industrial three-wire systems, which protect against electrical shocks and thermal overload. Additionally, Ground Fault Circuit Interrupters (GFCIs) quickly respond to changes in current, particularly useful in bathrooms and kitchens, contributing to electrical safety.