What can a shock beyond 20mA lead to?

A shock beyond 20 mA can lead to muscular contractions that make it difficult for a person to escape from the source of the electrical current. This occurs because the electrical current can interfere with the normal electrical signals in the body, causing muscles to contract involuntarily. When these contractions happen, the affected individual may find themselves unable to release their grip on the electrical source or move away, which increases the duration of exposure to the current and heightens the risk of severe injuries or complications.

In understanding this phenomenon, it's important to recognize that different levels of electrical current have varying physiological effects. At lower currents, individuals may experience tingling or minimal discomfort, but as the current increases, the risk of more severe muscular and systemic responses escalates significantly. In essence, the danger presented by currents greater than 20 mA primarily revolves around the potential for sustained muscle contractions that can compromise a person’s safety and ability to react appropriately during an electrical incident.