Solution:
•Before doing maintenance on your aquarium, turn the power off.
•Check equipment regularly for cracks, frayed wires, or broken bulbs, and repair or replace as needed.
•If equipment goes bad (i.e.: a heater breaks), shut off electricity to the tank before taking action.
•Plug equipment into GFCI (ground fault circuit interrupter).
•Use a drip loop to ensure water doesn’t travel to electrical outlets.
•Don’t lay power strips below the tank – mount them on the wall above the water level.
•Make sure the floor is dry, and wear rubber soled shoes when working on the aquarium
See
http://freshaquarium.about.com/od/problemsolving/a/grounding.htm?rd=1
The problem I faced is that even the brand new equipment such as pump have leaksge.... I have install the circuit breaker as a safety measure.