Why Half Your House Lost Power
When power dies in the kitchen and half the bedrooms but the living room stays lit, you're dealing with a partial outage. The most common causes:
- Tripped breaker: One branch circuit breaker flipped to OFF or the middle position after overload or a fault.
- Lost leg from the utility: Your home receives 240V split-phase service on two 120V legs. If one leg drops—damaged transformer, blown fuse at the pole, storm damage—half your circuits go dark.
- Main breaker or meter-base failure: Corrosion, a loose lug, or a failed main can kill one bus bar inside your panel.
- GFCI or AFCI nuisance trip: A single GFCI or arc-fault breaker protecting multiple downstream outlets can take out a whole branch.
Less common: aluminum branch-circuit wiring with failed connections, a damaged sub-panel feed, or a neutral fault that shifts voltage unpredictably between legs.
What to Check First (Safely)
Before you call, try these no-contact checks. Do not open the panel cover or touch any wires.
1. Check your main panel. Open the breaker-box door (the hinged cover that shows the rows of switches). Look for any breaker in the OFF position or sitting between ON and OFF. Flip it fully OFF, then back ON. If it trips again immediately, leave it off—that circuit has a fault.
2. Ask neighbors. If they also lost half their power, the utility lost a leg at the transformer. Call your power company first; they own everything up to the meter.
3. Test a known-dead outlet. Plug a lamp into an outlet that's not working. If it stays dark, move the lamp to a working outlet in another room to confirm the lamp itself is fine.
4. Check GFCI receptacles. In kitchens, baths, garages, and outdoor areas, press the RESET button on any GFCI outlet. One tripped GFCI can kill power to several downstream outlets.
If none of that restores power, or if you smell burning plastic, see scorch marks, or hear buzzing at the panel, stop. Cut the main breaker if safe to do so and call a licensed electrician.
Lost Leg vs. Tripped Breaker: How to Tell
A tripped branch breaker affects one circuit—maybe the kitchen outlets, or the upstairs hall lights. Flip it back on and you're done (unless it trips again under load, which means a short or overload).
A lost utility leg is different. You'll see a pattern: roughly half the house is dark, often in a checkerboard—some rooms fine, others totally dead, with no single breaker in the tripped position. Appliances on 240V circuits (electric range, dryer, water heater, AC condenser) may run weakly or not at all, because they need both legs.
Inside the panel, the two bus bars alternate down each column. Breakers on the left bus pull from leg A; breakers on the right pull from leg B. If leg B is dead at the meter or main lugs, every breaker on that side loses power even though the breaker itself looks ON.
You can't fix a lost leg. The utility must repair the transformer, service drop, or meter base. If the problem is between the meter and your main panel—failed main breaker, corroded lug, damaged service-entrance cable—a licensed electrician handles it. Either way, call us and we'll walk you through who to contact first or dispatch someone immediately if it's inside your system.
When a Partial Outage Is Dangerous
Most partial outages are inconvenient, not immediately hazardous. But watch for these red flags:
- Burning smell or visible char around the panel, meter, or any outlet. Cut power at the main and call 911 if you see flame or heavy smoke.
- Buzzing, crackling, or arcing sounds inside the panel. Indicates a loose connection generating heat.
- Lights dimming and brightening randomly in the working half. Suggests a floating neutral or severe voltage imbalance—can damage electronics and start fires.
- Warm or discolored breakers, bus bars, or panel enclosure. Sign of sustained overload or a high-resistance fault.
If you see any of these, do not wait. Turn off the main breaker (if you can reach it safely without opening the panel cover) and call (954) 602-0050 for emergency dispatch. We're available 24/7 across South Florida.
Even without drama, a lost leg left undiagnosed can overheat the working leg, trip AFCI breakers repeatedly, or damage 240V appliances that try to run on one leg. Get it checked within hours, not days.
What a Licensed Electrician Will Do
When you call 24/7 Electrician for a partial outage, here's the process:
1. Voltage test at the panel. We measure line-to-line (should read ~240V) and each leg to neutral (~120V each). If one leg reads 0V or fluctuates wildly, we know it's upstream—meter base, service drop, or transformer.
2. Inspect main breaker and lugs. We pull the deadfront (with the main off) to check torque on the main lugs, look for corrosion, pitting, or overheating on the bus bars, and verify the main breaker itself isn't failed internally.
3. Coordinate with the utility if needed. If the fault is at the meter or beyond, we'll document it and you'll call your power company. We can often expedite the process by providing technical details.
4. Repair or upgrade. If the issue is your main panel—failed breaker, burnt lug, undersized 100A service struggling with modern load—we quote the repair or panel upgrade up front. No work starts until you approve the price.
Most partial-outage calls are diagnosed within 30 minutes. If it's a simple tripped breaker you missed, we'll reset it and check the load on that circuit to prevent future trips. If it's a failed main or lost leg, we either make the repair immediately (if materials are on the truck) or schedule it for the next available window and provide temporary workarounds where safe.
Preventing Future Partial Outages
You can't prevent utility failures or lightning strikes, but you can reduce the risk of panel-side problems:
- Don't overload circuits. If you're tripping the same 15A or 20A breaker repeatedly—space heaters, window AC units, power tools—add a dedicated circuit. We run new home-runs from the panel to high-draw areas.
- Upgrade aluminum wiring connections. Homes built 1960s–70s often have aluminum branch circuits. Connections loosen over time and overheat. We retrofit with CO/ALR devices or pigtail to copper at junction boxes.
- Replace old panels. Federal Pacific, Zinsco, and some old GE panels have documented failures. If your house still has one, a panel replacement (typically 200A) is cheap insurance.
- Surge protection. A whole-house surge suppressor installed at the main panel protects against voltage spikes that can damage breakers and create nuisance trips.
For older homes—especially those that have never had a service upgrade—consider a panel inspection every five years. We check torque on lugs, verify breaker ratings match wire gauge, look for double-taps and backstabbed connections, and confirm your grounding and bonding meet current NEC requirements. Catches small problems before they leave you in the dark.
Explore our full range of electrical services or read more troubleshooting guides on the blog.
24/7 Emergency Service Across South Florida
Power out in half the house? Don't wait until morning—electrical faults can escalate, and a lost utility leg won't fix itself. Call (954) 602-0050 any time, day or night. We'll dispatch a licensed, insured electrician to your home or business with fully stocked trucks and diagnostic tools.
We quote pricing up front before any work starts—no surprise charges, no hidden fees. Whether it's a tripped breaker, a failed main lug, or a full panel upgrade, you'll know the cost before we lift a screwdriver. We come to you across South Florida, ready to restore power safely and quickly.