Basic Electrical Safety

Circuit Breakers and Electric Shock

This model can be used to help illustrate a point about electric shock and circuit breakers.  Figure #4 shows the circuit diagram of an unfortunate individual whose body has provided a ground path for a 220VAC source.  In this case the current that this individual is drawing will not even be enough to cause the circuit breaker to trip, as a result the current will be continuous.  This will be a case of electrocution where not only will the heart normal cycle stop, but internal organs will be heated in a destructive manner.

There is another reason why a circuit breaker tripping will not protect the human body from an electric shock.  Even if the current was enough to trip the circuit breaker, circuit breakers normally take a minimum of 1-1/2 cycles to open.  That means that the full voltage will contact the body and the resulting full current will still pass through the body, causing a potentially lethal electric shock.  Although circuit breakers are important safety devices, they do not provide protection from electric shock.