Step # 1. Check for Torn or Damaged Wires
Before you plug the string to check if it's working fine and there are no dud bulbs, examine the string for damaged insulation or torn wires. Problems in the wire, if not tackled beforehand, can cause leakage of current and result in electrocution. And if you do find exposed or torn wires along the length of the string, then get down to fixing the leak.