Half the House Lost Power and No Breaker Tripped? A Lost Leg

Half the house dead with no breaker tripped is a pattern, not a random outage. Homes are fed by two 120-volt legs from a 240-volt service. Lose one leg and roughly half the circuits die while the other half work. 240-volt appliances like the dryer, range, or AC fail or act strange. A dryer that runs but does not heat is a classic tell because the motor is 120-volt and the element is 240-volt.

First, map the pattern

Write down which rooms and which big appliances are dead. Check whether the dead half changes when a big load kicks on. Look at the lights. If some lights get brighter while others dim, that is a lost neutral, which is worse than a lost leg. A lost neutral lets voltages swing above and below normal and can cook electronics. Treat that as an emergency for anything plugged in.

Safe homeowner checks

1. Check the main breaker. Make sure it is fully on, not tripped to the middle. Do not open the panel cover.
2. Check GFCIs for a single room. A dead bathroom or kitchen counter is often a GFCI, not a lost leg. Reset it once. If it trips again, stop.
3. Check neighbors. If the neighbor has the same problem, call the utility first. The failure may be on their side.
4. Look at the meter and service drop from a distance. Do not touch. Note any burned smell, scorching, or hanging wire. That is utility territory.

Where the failure usually is

The failure is often outside the house: a utility connection, a burned lug at the meter, a failed service drop connection, or corrosion at the weatherhead. Inside, it can be the main breaker or panel bus. Diagnosis by pattern is what a tech does. If the dead half follows a big load, or the lights flicker and change brightness, stop and call. That is not a “reset it and see” problem.

Call the power company first

For a lost leg, call the power company first. It is their side more often than not, their check is free, and they can kill the service safely. Do not let a handyman open the meter can. Do not pull the meter. Do not touch the service drop. The utility will tell you whether the problem is theirs or yours. If it is yours, that is an electrician call.

What it costs

Utility checks are typically free. An electrician diagnostic visit is commonly $150–$350 depending on the area and after-hours charges. A main breaker or panel repair can run $300–$1,200 or more depending on parts and permit requirements. A service change is a bigger job. The exact number depends on what failed, but the diagnostic order is always the same: pattern first, utility second, electrician third.

Lost neutral warning

A lost neutral is the one that scares techs. Lights that brighten and dim, a buzzing panel, or electronics dying one by one are signs. Unplug sensitive gear until it is fixed. Do not keep running the dryer or AC to “test” it. The voltage swing can damage the compressor, the control board, and anything with a motor.

STOP: Nothing inside the panel beyond flipping a breaker. Never touch the meter, the meter can, or the service drop. Treat a lost neutral as an emergency: unplug sensitive electronics and call the utility. If you see scorching, smell burning, or hear buzzing at the panel, get out and call for help.