First, carefully evaluate the situation before doing anything.
1. Never go into a basement even partially filled with water. Wait for the electric company, fire department or other professional to shut down all electricity and remove the meter.
2. Keep in mind that water damaged electrical equipment is likely ruined. This type of equipment is just not able to withstand damage caused by submersion. Much depends on the type of equipment, the depth of the water, and how long submerged. Even equipment that appears to be fine may be dangerous to operate and have a much shorter life span.
. Have your home's entire electrical system carefully checked over by a qualified electrician to make sure all wires are in good condition and properly grounded.
4. Never go into a water filled basement alone. It will be dark and you can easily lose your balance and fall. Use rubber chest waders and bring a clip-on flashlight so your hands will be free. Watch for contaminated water getting into the waders and be wary of tripping hazards. Alway have someone nearby in case you need help.