Do you have a boat with a European type 220 volt AC system?

Beware of boatyards using American type 220 volt 3 phase power systems, they may be fatal. In Europe single-phase power is used. In the United States, 220 volt is 3 phase (110 volt is single phase). These are not the same. European single phase will have three wires, hot, neutral and ground. American 110/220 volt systems have four wires, hot, hot, neutral and ground. A marina using the 3 phase system may supply power to a boat using the 220-volt single phase system simply by connecting it to the two hot wires and the ground. This will indeed give you 220 volts on your boat. However, eliminating the neutral wire means that the neutral to ground circuit will not be 0 volts as you would expect but 110 volts. If the neutral wire on your boat is connected to the boat’s ground system (which it should not be) and the boatyard’s ground is less than perfect then the entire ground system of the boat will be at a potential of up to 110 volts; you could get a lethal shock by touching just about anything metal on your boat. Also, stray currents could cause a similar problem.

This can happen as the following shows:

Recently a boat hauled at “Trinidad’s largest boatyard” experienced a near fatality. The boatyard electricians had connected up the “American style” 220, to a “European style” 220 yacht. Apparently, the boatyard grounding system was incomplete and failed. One of the owners climbed a ladder to board the boat, and when she reached for a stay to climb on-board, she became the ground path – taking the shock and being unable to release or move. Her yells were heard by others who went immediately to her aid, only to receive shocks as soon as they touched her. Finally, welders nearby heard the commotion and ripped all the power connections from the source panel, breaking the circuit. Luckily, she received only burns and spent days recovering from muscle damage. It was very nearly fatal. It was later learned that a similar incident had occurred in this same boatyard about a year earlier – that person was not so lucky and died, from a brain hemorrhage that resulted from his fall when he experienced the same electrical ground fault. The boatyard has accepted no responsibility for either event, has not responded to letters from those involved, and refused to compensate for any of the expenses – even the additional lay days that were a result of this electrical system failure.

What can you do to protect yourself?

Make sure your boat’s electrical system, especially the ground, is correctly wired and in good condition. Don’t “bet your life” on the quality of the boatyards ground system, create your own boatyard ground by driving a copper pipe several feet long into the ground and connecting it directly to your boat’s ground system. Best of all use an isolation transformer between boatyard power and your boat.

http://www.safetyandsecuritynet.com/