Electrical hazards are one of the many hazards that can occur in a flooding incident involving potential exposures to harmful substances, or contact with energized surfaces or energized water itself.  During a flood, a hazardous flow of electric current can occur from submerged or damaged electrical equipment and the associated risk of electrocution from water damaged appliances. During the cleanup and recovery phase, possible electrical hazards include using powered hand tools in a wet environment or reusing electrical appliances, lighting or other electrically powered equipment which was damaged and no longer safe to use.

Fatal factors

The electrocution hazard depends on factors including the position of the body in contact with various surfaces, the body parts in contact with the water, whether a Ground Fault Circuit Interruptor (GFCI) was used for personal and circuit protection, the nature of the damaged equipment which electrified the water, and dissolved components or contaminants in the water. In a flooding situation, GFCIs or dual function arc fault circuit interrupters and GFCIs installed in the main circuit board automatically shut off the electricity and are particularly important for creating safe conditions. 

Electricity can present a special hazard because of a likely or possible short circuit, electrical components under water, or water contacting electrically powered equipment, lighting, appliances or other electrically powered equipment.  Electrocution can occur when someone enters a flooded basement which contains the electrical panel.  Electrocution can also occur when standing in water while turning off a breaker, or turning off electrical equipment with submerged or damaged electrical outlets. 

Disconnect all the loads from the grid before flood recovery. Utilities must shut off power to the occupied structure before anyone can safely enter flooded areas. Removing a circuit breaker or disconnect does not eliminate the hazard. The only safe way to reduce the electrical hazard is to remove the grid feed meter. This should only be done by an experienced electrician. 

Nearly all electrically-powered equipment or utilities are not intended to be safe after submersion or saturation with water.  Potential replacements include the building’s electrical distribution system, wires, cables, circuit breakers and panels, switches, outlet receptacles, lights, damaged electrical furnaces, hot water heaters, appliances, motors, fans, or air conditioners.  In addition the grounding systems must be inspected for damage and functionality.1

What to do

To ensure safety:

• The power company or a licensed electrician must disconnect the grid-feed meter before entering the building. Then disconnect main switch and all circuits.

• Pump out all flood water before attempting any work on electrical systems.

• An electrician must check the electrical distribution system especially for ground faults, remove covers and clean all outlets and check and replace fuse or multi-breaker boxes.  Replace damaged circuit breakers or breakers that have been submerged.

1 Popular Mechanics: http://www.popularmechanics.com/adventure/outdoors/tips/a8231/4-rules-for-electrical-safety-after-a-flood-14261065/