I found this info on another website but i am surprised this question hasnt been put forward to the Electrical Forum :dizzy2:
"Building sites need flexible power but the chance of contact is much greater from choppping cables, etc., so it is transformed down to 110V, BUT it is also connected to earth at the centre tap of the 110V winding. This means that unless you are most unfortunate and touch both wires at once (110V), the most shock you should get to earth is only 55V Much safer, but needs heavier wires to carry the power."
"The reason why building sites use 110 is partly safe of the centre taped transformer and mostly due to the current being higher to power more powerful tools I.e.6000watt drills that pull only 4-8amps instead of 26amps at 230volt that's all,"