If you are using any form of electrical device in your home brewing setup, such as a march pump or heating element, you should always be using a GFCI device to help protect against the possibility of severe electrocution. During a normal home brewing session, there is a lot of liquid being transferred or used for cleaning and cooling. The possibility of that liquid coming into contact with an electrical device or exposed wire is a serious concern. GFCI adapters are relatively inexpensive (around $15), and they just might save your life. A GFCI or Ground Fault Circuit Interrupter is a device that cuts the flow of electricity when the electrical current is not balanced between the energized conductor and the return neutral conductor.
GFCI adapters are sold at home supply stores and are also available at most home brewing outlets. You can find a good deal on one here: