Power Out in Half the House? Why It Happens and Who to Call

Half the lights work and half do not. The refrigerator runs, but the living room is dark. The dryer hums without heating, and the central air will not start. Having the power out in half the house while nothing in the panel looks tripped is one of the most telling electrical symptoms a homeowner can see, and it usually has nothing to do with a single circuit. In most cases, the home has lost one of the two “legs” of its incoming 240-volt utility service, or the main breaker is failing.

That distinction matters because the fix is not flipping breakers. It is a phone call to your utility, and sometimes to a licensed electrician after that. The homeowner side of the job is short: confirm the pattern, check whether neighbors are affected, reset the main once if it looks tripped, turn off large appliances, and report it. Everything beyond that involves the meter, the service drop or the panel interior, which only the utility or an electrician should touch.

Power Out in Half the House: What It Usually Means

Most North American homes receive power as split-phase service. Three wires run from the utility transformer to your meter: two “hot” legs and a neutral. Each hot leg carries about 120 volts relative to the neutral, and the two together supply 240 volts for big appliances. Inside the panel, breakers alternate between the two legs, so roughly half your 120-volt circuits ride on one leg and half on the other.

When one leg is lost, every circuit on that leg goes dead at once, while the other half of the house keeps working normally. Large 240-volt appliances like an electric range, dryer, water heater, well pump or heat pump receive only partial power, so they may hum, run weakly, show their display but not heat, or refuse to start. That pattern is the signature of a lost leg.

Common causes include:

• A blown fuse or failed connection on the utility transformer, often after a storm, high winds, a tree branch contact, or heavy heat-wave loads
• A damaged or corroded service drop (the overhead wires) or a failed underground service cable
• A loose or burned connection at the meter base
• A failing main breaker that has stopped conducting on one side

Only the last of those is inside your panel, and even that one is not something a homeowner should open up.

Quick Safety Checks You Can Do

These steps take about ten minutes and require no tools beyond a flashlight. Do not remove the panel cover, touch the meter, or use a meter or tester on anything.

1. Confirm the pattern. Walk through the house and note which rooms and outlets work. If the dead areas are scattered across the home rather than grouped in one room, and big appliances are acting strangely, a lost leg is likely.
2. Check the neighbors. Look outside or text a neighbor. If others on your street have partial power or dim lights too, the problem is on the utility side. Report it right away.
3. Look at the main breaker. Open the panel door and look at the large main breaker at the top (or in a separate box near the meter). If it is off or in a middle position, push it firmly to OFF and then back to ON, one time only. If it trips again, or does not change anything, leave it alone.
4. Turn off large 240-volt appliances. Switch the thermostat to OFF and turn off the electric dryer, range, water heater (at its breaker, if labeled) and any well pump control. Motors and compressors can be stressed by running on partial voltage, and some appliances can feed odd voltages back into the dead half of the house.
5. Unplug sensitive electronics on the working half if lights are flickering, dimming or brightening, which can signal unstable voltage.
6. Look for obvious outside damage from a distance: a sagging service wire, a tree limb on the line, or a scorched or damaged meter. Stay well away from any downed or low wires and report them to the utility as an emergency.

When the Circuit Breaker Is Not Tripped but There Is No Power

People often search “circuit breaker not tripped but no power” expecting a single bad breaker. If the outage is confined to one room or one run of outlets, that may be true, and the cause is usually a hidden tripped GFCI or a loose connection on that circuit. When the outage spans many rooms with no common thread except that they are on alternating breakers, the problem is upstream of the branch breakers entirely.

The same logic applies if the whole house went dark with nothing tripped. A whole-house outage with the main breaker still on almost always means the utility has lost power to your service. Check the utility’s outage map or call their outage line. A tripped main breaker is less common, and if it trips again after a single reset, an electrician needs to find out why.

Who to Call First

When you have the power out in half the house, call the utility first for any partial-house or whole-house outage. Tell them you have “partial power” or “half power” and that large appliances are not working correctly. That phrase helps the dispatcher recognize a lost-leg problem. Utility crews are responsible for everything from the transformer up to and including the connections at your meter, and most utilities do not charge for repairing their own equipment.

Call a licensed electrician if the utility confirms their side is fine, if the meter base or main breaker is damaged, or if you see scorching at the panel or meter. Repairs to the meter base, service entrance cable or main breaker are generally the homeowner’s responsibility and often require a permit and coordination with the utility to disconnect service safely.

Warning Signs That Mean Act Now

• Lights in some rooms becoming very bright while others dim, which can indicate a lost neutral (a dangerous condition that can damage electronics and overheat wiring)
• A burning smell, buzzing or crackling from the panel or meter
• Visible scorching, melted plastic or a warm panel cover
• Sparking at the service drop or meter

Any of these is a fire hazard. If you can safely reach the main breaker, turn it off, keep everyone away from the panel and meter, and call the utility immediately. If anything is smoking or sparking, leave the house and call from outside.

Staying Comfortable While You Wait

Utility repairs for power out in half the house are usually completed within hours, though storms can stretch that out. Keep the refrigerator and freezer closed if they are on the dead side. A portable power station (a battery unit with standard outlets) can run phone chargers, a lamp, a small fan, a CPAP machine or a modem and router without fumes, which makes it a safe indoor option. Never run a gasoline generator indoors, in a garage, or near windows, and never plug a generator into a wall outlet to “backfeed” the house. That can electrocute utility workers and damage your wiring. Whole-home generator connections require a transfer switch installed by a licensed electrician.

Typical Costs

Utility-side repairs to a transformer or service drop are normally handled by the power company at no cost to you. If the problem is at your meter base or main breaker, an electrician’s repair can range from a few hundred dollars for a connection repair or main breaker replacement to $1,500 or more for a meter base or service entrance replacement, and a full panel replacement often costs more than that. Permits and utility coordination fees vary by area.

When to Call a Licensed Professional

• The utility confirms their equipment is working and you still have half power
• The main breaker trips again after one reset, or will not reset
• There is any scorching, heat, buzzing or burning smell at the panel or meter
• Lights are flickering or dimming across the whole house (call the utility first, then an electrician)
• You want a transfer switch, generator inlet or panel upgrade, which requires a licensed electrician and a permit