Electric shock: a hidden danger in everyday shipboard work

An electric shock can cause burns, serious injuries, even death. The outcome depends on factors including the voltage, the amount of current, as well as the path and time that the current takes to pass through the body.

It does not take a large current through the body to cause serious harm. The US Occupational Safety and Health Administration notes that currents above 10 milliamperes can cause involuntary muscle contractions. At higher levels, consequences can include extreme pain, respiratory arrest and possible death. The rhythmic pumping of the heart ceases at around 1 amp.

Voltage also matters because it helps drive current through resistance. Electrical systems on ships operate at different voltages, from low-voltage signal equipment to switchboards operating above 1,000 volts. Generally speaking, care should be exercised when the voltage exceeds 50 volts. The actual danger depends on the circumstances, including the condition of equipment, the electrical system and the environment in which work is carried out. Water, sweat and humidity all increase conductivity on the body’s surface, thus increases the risk on ships.

The risk points onboard Ships have several electrical distribution systems and voltages vary from as low as 5 volts for signal power to well over 1000 volts in switchboards. This is typically stepped down to 440 volts for machinery and 220 volts for lighting and sockets used for portable equipment.

This story was originally published by Hellenic Shipping News. Read the full story at Hellenic Shipping News →