Anyone who has access to live electrical equipment must be fully aware of first-aid and safety procedures related to electric shock as described in relevant safety acts.
Copies of these safety procedures should be displayed on board ship.
Electric shock is due to the flow of current through your body. This is often from hand to hand or from hand to foot.
A shock current as low as 15 mA a.c. or d.c. may be fatal. Obviously the size of shock current is related to the applied voltage and your body resistance.
Unfortunately, your body resistance goes down as the applied voltage goes up.
This means that the shock current is further increased at high voltages.
The size of your body resistance also depends on other factors such as your state of health, the degree of contact with live wires and the perspiration or dampness on your skin.
Typical dry full-contact body resistance is about 5000 Ohm at 25 V falling to about 2000 Ohm at 250V.
Voltages of about 60 V and below are regarded as reasonably safe for portable hand tools.
This is why special step-down isolating transformers are used with portable tools and hand lamps.
These transformers supply the tool or lamp at 110 V a.c. but because the secondary winding is centre-tapped to earth, the maximum shock voltage to earth is 55V a.c.
Electric shock is often accompanied by falling, which may cause additional physical injury and require first-aid action.
If the shock victim is unconscious, resuscitation must take priority over first aid methods.
Check the resuscitation techniques described on the electric shock posters displayed on your ship.