Backfeed

Backfeed happens when a generator is wired or plugged into a house without a proper transfer switch. Power can travel back through the meter onto the lines outside. CPSC says to never try to power the house wiring by plugging the generator into a wall outlet, a practice known as backfeeding.

This is extremely dangerous. It puts utility workers and neighbors on the same utility transformer at risk of electrocution. A line that looks dead can be live. Use a portable generator only with cords to appliances, or have a licensed electrician install a transfer switch. See emergency electrical help.