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Homeowner electrical problem

Half the House Has No Power: What Does It Mean?

Short answer: When half the house has no power, the most likely cause is a lost leg of your 240 volt service. If one of the two 120 volt legs is interrupted, roughly half the circuits go dead and 240 volt appliances like the AC and dryer stop or run poorly. The fault can be on the utility side (the lines, the transformer or the service drop) or on the house side (the meter base, main breaker or panel connections). Call your electric utility first, and treat this as urgent either way.

Your call connects you with an independent local electrician who serves your area.

Illustration of a dark kitchen lit by a flashlight during a power outage

What homeowners usually notice

  • Lights and outlets in some rooms work normally while others are completely dead.
  • The air conditioner, heat pump, dryer or electric range will not run, or hums without starting.
  • Some lights glow dim or flicker, especially when a large appliance tries to start.
  • Neighbors have full power, or the partial outage began during wind or a storm.

What to do right now

  • Turn off large 240 volt appliances (AC or heat pump, dryer, water heater, range) at their controls to protect motors and elements.
  • Call your electric utility and describe it as partial power or a possible lost leg; they check their side at no charge to the meter.
  • Check the main breaker and branch breakers; reset any that are tripped, once.
  • Look outside, from a distance, at the service drop to see if a tree limb is on the line or the connection at the house looks damaged. Stay well away from any wire.
  • If the utility finds their side is fine, call a licensed electrician to check the house side.

Likely causes

Utility-side problem

A blown fuse on the pole transformer, a damaged overhead line or a failing underground connection can drop one leg. The utility repairs these.

Damaged service drop

Tree limbs, storm wind or ice can pull or strain the cables running to your house. With Birmingham's hills and mature trees, limb damage to service drops is common after storms.

Failed connection at the meter base

Corroded or loose lugs in the meter base can lose contact on one leg. This is usually the homeowner's equipment and needs an electrician.

Main breaker or panel bus failure

A worn main breaker or a burned connection where the service wires land in the panel can interrupt one leg.

Safe checks you can make

  • Note which rooms, appliances and circuits are dead and which work.
  • Ask a neighbor whether they have full power.
  • Look from a safe distance for a sagging or damaged line, scorched meter base or pulled mast. Do not touch anything.

Leave outlet covers, switch plates and the panel cover in place. Noting what you see and hear is enough; testing inside boxes belongs to an electrician.

Is this something you can fix yourself?

The honest answer is that very little of this is a homeowner repair. What you can safely do is reset a tripped breaker once, shut down big appliances, and call the utility. If the problem is in the meter base, the service entrance or the panel, it involves the unfused service conductors, which can carry dangerous current even with the main breaker off. Never pull the meter, open the panel or touch the service drop. The utility repairs its side; a licensed electrician repairs yours.

When professional help is the right call

  • The utility confirms their side is working but half the house is still out.
  • You see scorching, melting or rust at the meter base or panel.
  • Lights are brighter than normal in some rooms and dimmer in others, which can point to a lost neutral.
  • The service drop is sagging, pulled from the house or hit by a limb.

Safety first. Treat any downed or sagging line as live and keep everyone, including pets, well back; call the utility and 911 if a wire is on the ground. If lights surge very bright, electronics fail, or you smell burning at the panel or meter, turn off the main breaker if you can reach it safely and call for help right away. Smoke or fire means leave and call 911.

Illustration of an electrician beside a standby generator
Illustration only. People shown are not contractors listed on this site.

What an electrician typically checks

Once the utility confirms their side is working, an electrician measures voltage at the meter and panel to find where the leg is lost. They inspect the meter base lugs, service entrance cable, main breaker and panel bus for corrosion, looseness or heat damage, and they check the neutral, since a lost neutral can cause dangerous voltage swings.

Repairs may include replacing the meter base, repairing the service mast or entrance cable, or replacing a damaged main breaker. Some of this work requires a permit and coordination with the utility. Related work falls under meter base repair and panel service.

Keeping it from coming back

Have trees trimmed away from the service drop by professionals qualified to work near lines, and report sagging or rubbing lines to the utility. Older meter bases and panels in many Birmingham neighborhoods have decades of heat cycling and humidity behind them, so corrosion is worth watching for. A periodic inspection can catch a failing connection before it drops a leg.

Repairs and services

Services that usually solve this

Similar problems

Half the House Has No Power: questions homeowners ask

Your home gets two 120 volt lines from the utility, called legs. Together they supply 240 volts for large appliances. If one leg is interrupted, about half your 120 volt circuits go dead and most 240 volt appliances will not run properly.

Call the utility first. They are responsible for everything up to and usually including the meter, and they can tell you whether the problem is on their side. If they find their side is fine, a licensed electrician should check the meter base and panel.

It can be. A central AC or heat pump running on one leg may hum without starting, overheat and damage its compressor or fan motors. Turn it off at the thermostat until full power is restored.

When one leg is lost, circuits on that leg can back-feed weakly through 240 volt appliances, making lights glow dim. Lights that go very bright in some rooms and dim in others may mean a lost neutral, which is more urgent and should be reported right away.

Stay away from the line and anything it touches, and keep others away. Call the utility to report it, and call 911 if a wire is down on the ground. After the utility makes its side safe, an electrician may need to repair the mast or meter base on your house.

Yes. A main breaker can fail internally on one pole, or the connection where it meets the panel bus can burn. The result looks just like a utility-side lost leg, which is why measuring voltage at the meter and panel is the first step.

Ready when you are

Not sure how serious it is?

Call and describe what you're seeing. You'll be connected with a local electrician who can advise on next steps.

Your call connects you with an independent local electrician who serves your area.