I have a shed in my back garden that has both lighting and power outlets that do not work. The fuse swith on the main fuse board in the house has not tripped the fuse box in the shed is on and the wiring appears to be in place. I have an Earth Leakage Curcuite Breaker next to the main fuse box with is OFF. Could this be the reason for my power shortage and if not what else could i check?