What is considered a fatal electrical current flowing through the human body?

The threshold of 20 milliamperes is considered to be a fatal electrical current flowing through the human body because it aligns with the commonly accepted understanding of how electric shock can affect bodily functions. At this level of current, individuals may experience muscular contractions that can prevent them from escaping the source of the shock, leading to prolonged exposure. Additionally, around this amount of current, there is a significant risk of ventricular fibrillation, which can result in cardiac arrest if not treated promptly.

Understanding electrical safety and the effects of current on the human body is crucial for anyone working with or around electrical systems, especially in amateur radio operations. Recognizing these thresholds helps in implementing safety measures to prevent accidents.