Final answer:
The two major hazards of electricity are thermal hazards, which can cause fires, and shock hazards, which can harm or kill a person. Protection systems like circuit breakers and insulation are used to prevent these dangers.
Step-by-step explanation:
The two major hazards of electricity are thermal hazards and shock hazards. A thermal hazard occurs when excessive electric power causes undesired thermal effects, such as overheating that can lead to a fire. A shock hazard happens when electric current passes through a person, ranging from being mildly painful to potentially lethal. Understanding the severity of electric shocks involves considering factors such as the amount of current, the path it takes through the body, the duration, and the AC frequency.
Systems and devices like circuit breakers and fuses are designed to prevent these hazards. They work by interrupting the flow of electricity in the event of an overload or a short circuit, which prevents overheating and minimizes the risk of fire, while grounding and insulation are used to protect against shock hazards.