Avoid electrical contact when working in awkward positions. If you must work in an awkward or unbalanced position and reach with your tools, use insulating cover up material on the tools to avoid contact with live conductors. There is a device which can protect you even in these circumstances. This is known as a residual current device (RCD) or a ground fault interruptor (GFI). This measures the current to the load, in the phase conductor, and the current coming back from the load, in the neutral conductor, and if there is even a small discrepancy it assumes this is a fault current to earth or ground and switches off the supply. For protection against electric shock devices rated at 30 mA are reccommended as this is less than the current needed to stop a human heart.