⚠️ Lights Getting Brighter or Appliances Buzzing Loudly — Turn Off the Main Breaker Now
If any lights are getting noticeably brighter, appliances are humming or running faster than normal, or you hear buzzing from the panel or meter area — the neutral conductor has failed or is failing. One leg of your service is running at potentially 150–180 volts instead of 120 volts. This will destroy refrigerators, televisions, and computers within minutes. Turn off the main breaker at the service panel immediately and call a licensed electrician and your utility company. Do not restore power until the neutral is repaired.
⚡ Quick Summary
- Some circuits dead, all breakers on, no brightening: one hot leg of the service is down — call utility (if storm-related) or electrician
- Some lights dim + others brighten: neutral failure — turn off main breaker immediately, call utility and electrician
- 240V appliances (dryer, AC, oven) won't run: one leg is missing — 240V loads need both legs; 120V loads on the working leg still function
- Issue appeared during or after a storm: likely utility service-drop failure — call your utility company's outage line first
- Do not open the panel cover, touch service conductors, or attempt to tighten any connections — this is above the breakers and is utility and licensed electrician territory
Understanding Split-Phase Service: Why Half the House Goes Dark
Every home in North America receives power from the utility as a split-phase 120/240V service. The service transformer produces 240V between two hot conductors (L1 and L2) and provides a center-tap neutral point at 120V relative to each leg.
⚡ Your Home's Three Service Conductors
✅ L1 — Hot Leg 1
120V to neutral
Feeds roughly half the 120V circuits in the home — odd-numbered breaker positions in most panels. If this leg fails, all circuits on it go dead. 240V loads (dryer, AC, oven, well pump) also stop functioning.
✅ L2 — Hot Leg 2
120V to neutral
Feeds the other half of the 120V circuits — even-numbered positions. If this leg fails, all circuits on it go dead while L1 circuits continue working normally. Again, 240V loads stop.
⚠ Neutral — Return Path
Current return for all circuits
Carries return current for every 120V circuit. If the neutral fails, the two legs are no longer referenced to ground independently — voltage redistributes, causing some circuits to run at dangerously high voltage and others at too-low voltage simultaneously.
The Two Scenarios: Lost Leg vs. Neutral Failure
Half-house outages fall into two distinct categories with very different urgency levels. Identifying which one you have determines your next action.
🟠 Scenario A — Less Dangerous
One Hot Leg Down (L1 or L2)
Specific circuits are dead; circuits on the other leg work normally. No brightening. 240V appliances (dryer, AC, oven) won't start. All breakers appear on. The pattern is clean: one set of circuits dead, the other set fine.
Caused by: utility service-drop failure (most common after storms), meter base connection failure, or degraded bus bar stab in the panel. The other half of the house operates normally at correct voltage.
🔴 Scenario B — Emergency
Neutral Conductor Failing or Failed
Some lights dim simultaneously while others get brighter. Appliances hum unusually loud. Electronics behave erratically. Voltage is unstable — changes as loads switch on and off. This is NOT clean half-and-half.
The dangerous condition: one leg may be running at 150–180 volts. Refrigerators, TVs, computers on that leg can be destroyed in minutes. The neutral failure point itself generates intense heat. Turn off the main breaker immediately.
Severity Classification
Common Causes of Half-House Power Loss
01
Utility Service-Drop Failure — Most Common After Storms
The overhead conductors running from the utility transformer to the weather head on your home can fail at several points: a conductor can physically break (in high winds or ice loading), the connector at the weather head can corrode and lose contact, or the splice between utility wire and service entrance cable can degrade. Loss of one hot leg is the most common result. Your neighbors may have full power — the failure is between your home and the transformer, which may serve only your property.
Pattern: occurred during or shortly after a storm; half the circuits dead; no brightening; breakers all appear normal. Call your utility company's outage line — this is utility property and their repair responsibility up to the weatherhead. An electrician handles the homeowner side of the weatherhead connection if needed.
02
Loose or Corroded Neutral Conductor — Most Dangerous
The neutral conductor connects at several points from the utility transformer to the neutral bus in your service panel: at the utility transformer terminal, in the overhead cable, at the weatherhead, at the meter base, and at the panel neutral bus. Corrosion at any of these points creates resistance in the neutral path. Under load, that resistance generates heat, which worsens the corrosion, which generates more heat — a progressive failure. The voltage imbalance this creates can damage or destroy electronics and appliances on the over-voltage leg within minutes.
Pattern: lights brighten on some circuits while dimming on others; behavior changes as loads turn on and off; buzzing from panel or meter area; appliances running unusually loud or fast. Turn off main breaker immediately. Do not attempt to locate or tighten the neutral connection yourself — service-entry conductors are always energized even with all breakers off.
03
Meter Base Connection Failure
The meter base is where the service-entrance conductors terminate and connect to the meter. The lugs holding these conductors — made of aluminum in most older installations — are subject to oxidation and thermal cycling that causes them to loosen over years. A loose meter base lug on a hot leg: half the home loses power and 240V loads fail. A loose meter base neutral lug: the dangerous neutral float condition. Water intrusion into the meter enclosure accelerates both failure modes.
Pattern: partial outage with no obvious storm cause; symptoms may have been intermittent before becoming persistent; the meter area may show signs of water entry or corrosion. The meter base and its connections are on the line side of the service — always energized at utility voltage. This is utility and licensed electrician territory.
04
Failed or Degraded Panel Bus Bar — One Phase Dead
Inside the service panel, breakers connect to bus bars fed by the two service legs. A bus bar with a failed connection to its service lug, or a breaker that has lost contact with the bus bar stab, can remove an entire phase from service. All breakers on that bus position appear to be on, but none of the circuits they control have power. This is a panel-level failure that is on the load side of the service entrance — accessible to a licensed electrician but requires the main breaker to be off.
Pattern: half the circuits dead; all breakers appear to be on; no storm preceded the outage; no brightening of other lights. An electrician can diagnose this from the load side with the main breaker off — no utility involvement required. Requires panel-level inspection and repair.
05
Utility Transformer Partial Failure
The utility transformer supplying the home occasionally fails in a way that produces only one leg of the split-phase service rather than both. This is less common than service-drop or meter base failures but produces identical symptoms — half the home without power, 240V loads dead. Only the utility can diagnose and correct this. If your neighbors on the same transformer also show symptoms (flickering, partial outages), the transformer is the likely source.
Pattern: neighbors also reporting partial or unusual power; multiple homes on the same block affected; utility acknowledges an equipment issue when called. Call the utility's outage line — this is entirely their responsibility and requires their line crew to address.
What to Observe and Who to Call
1
First: are any lights getting brighter?
Walk through the whole home. Any room where lights appear unusually bright or any appliance running faster or louder than normal = neutral failure. Turn off the main breaker immediately and call your utility's emergency line and a licensed electrician. This is the only step you need if the answer is yes.
Some lights brighter → Neutral failure. Turn off main. Call utility + electrician.
No brightening → Continue to step 2
2
Check whether neighbors also have partial or full outages
Step outside and ask a neighbor if they have full power. If they also have issues, or if you can see street lights on one side of the street but not the other, the problem is at the utility level — transformer or service-drop. Call your utility's outage line.
Neighbors also affected → Utility outage. Call utility outage line.
Neighbors have full power → Failure is at your home. Continue.
3
Check the service panel without opening the cover
Stand in front of the panel with it closed. Do you smell anything burning? Do you hear buzzing from inside the panel? Is the panel enclosure warm? Any of these: turn off the main breaker and call an electrician. Without opening: are all breakers in the fully ON position? Note any that appear to be in the middle (tripped) position and reset them properly.
4
Map which circuits are dead
Using a lamp or phone charger, test which outlets and circuits are dead. Does the dead-circuit pattern alternate with live ones? Circuits are typically distributed alternately between L1 and L2 in a panel — every other position. If every other circuit is dead, one leg is down. Tell the electrician this — it confirms which service leg is the issue.
5
Call your utility and a licensed electrician
For utility service-drop failures (especially storm-related): start with the utility's outage line. They repair from the transformer to the weatherhead at no charge. An electrician handles from the weatherhead into the home. If the issue is inside the panel or at the meter base: electrician. If genuinely uncertain: call both. While waiting, avoid using large 240V appliances and unplug sensitive electronics if there's any uncertainty about voltage stability.
What Your Pattern Tells You
| Pattern Observed | Most Likely Cause | Action |
|---|---|---|
| Some lights brighter, others dimmer simultaneously | Neutral conductor failing — emergency | Turn off main breaker. Call utility + electrician immediately. |
| Half the circuits dead; no brightening; storm occurred | Utility service-drop leg failure | Call utility outage line. They repair the service drop. |
| Half the circuits dead; no storm; all breakers on | Meter base lug failure or panel bus failure | Call a licensed electrician. |
| 240V appliances dead; 120V circuits on one side work | One service leg is missing | Call utility (storm) or electrician (no storm). |
| Buzzing or burning smell from panel or meter | Arcing at a service connection — emergency | Turn off main breaker. Call electrician immediately. |
| Symptoms intermittent; worsen under heavy load | Loose service lug or neutral — developing fault | Call electrician — do not wait. Progressive failure. |
| Neighbors also have partial or unusual outages | Utility transformer or distribution line | Call utility outage line only. |
Why 240V Appliances Fail First in a Lost-Leg Event
240-volt appliances — dryers, electric ranges, HVAC systems, water heaters, well pumps — require both L1 and L2 to operate. Lose either leg and they simply won't start. 120V circuits on the surviving leg continue working normally. This creates a distinctive pattern: half the 120V circuits work, but every 240V load in the house is dead. If this is your pattern with no brightening anywhere, you've lost one hot leg from the service drop — an inconvenient but not immediately dangerous condition while you wait for the utility or electrician.
T.A.
From the Expert
"The neutral failure scenario is the one I treat as an emergency every time. I've seen refrigerators with burned-out compressors, televisions that caught fire internally, whole-house audio systems destroyed — all from neutral float events where the homeowner saw the lights brightening and didn't understand what it meant. The voltage on the overloaded leg during a full neutral float can reach 180 volts or higher. At that level, appliances rated for 120V see 50% over their design voltage — and most of them fail within minutes, not hours. My advice is simple: if lights are getting brighter anywhere in the house while other circuits are dimming or dead, that's a main breaker-off situation, not a wait-and-see situation. The cost of a service call is trivial compared to replacing a refrigerator, a TV, and a furnace control board. The lost-leg scenario — where it's just a clean half-and-half with no brightening — I take more calmly. Uncomfortable, but not immediately destructive. Call the utility, avoid 240V loads, and wait."
— T.A., NFPA CFI-1 · Licensed Electrician · CHFM · OSHA 30
What To Do vs. What Not to Do Right Now
✓ Safe Actions While You Wait
- Turn off the main breaker immediately if any lights are brightening
- Check whether neighbors have power to determine if it's the utility
- Sniff near the panel (without opening it) for burning smell
- Unplug sensitive electronics (TVs, computers, appliances) if there's any voltage instability
- Call your utility's outage line if storm-related or neighbors are also affected
- Call a licensed electrician for internal panel or non-storm causes
✗ Do Not Do Any of These
- Open the panel cover or touch any conductors — service-entry wires are always live
- Attempt to tighten any lug, screw, or connection in or near the panel
- Reset breakers repeatedly during voltage instability
- Continue using 240V appliances if one leg is suspected missing
- Access or touch the meter base — always line-side energized at utility voltage
- Dismiss brightening lights as "probably nothing" — this is always a neutral event
Frequently Asked Questions
My power company says the line is fine. Could the problem still be on my property?▾
Yes — and this is a common scenario. The utility typically tests their service up to the weatherhead (the fitting at the top of the conduit entering your home). If they report their service is intact, the problem is at the weatherhead connection, the service entrance cable, the meter base, or inside the service panel. All of these are the homeowner's responsibility, not the utility's. The most common location after the weatherhead: the meter base lugs. These connections are made of aluminum conductors landing on aluminum lugs and are susceptible to oxide buildup over 20–30 years of service. An electrician with the utility confirming the service is intact can work on the meter base (with the utility pulling the meter to de-energize the base) and the panel. If the utility says their service is fine and you still have a half-house outage or voltage instability, call a licensed electrician — the fault is on your side.
Is a half-house outage covered by homeowner's insurance?▾
Potentially — for appliance damage caused by a voltage surge or neutral float event. Standard homeowner's insurance often covers sudden and accidental damage to appliances from power surges, though this varies significantly by policy and requires documentation. If a neutral failure destroyed your refrigerator, television, or other appliances, document the damage with photos before disposal, get the electrician's written assessment of what caused the failure, and file a claim. Some policies also cover the cost of a power surge investigation by a licensed electrician. What insurance typically does not cover: the electrical repair itself (that's maintenance), and damage from a condition that was gradual and long-standing rather than sudden. Consult your policy or agent — but document the damage carefully before any repairs are made.
Can I use a generator while half the house is without power?▾
Carefully and only with correct setup. A portable generator connected to the home must be connected through a proper transfer switch — never by backfeeding through an outlet, which is both dangerous and illegal. If the cause of the half-house outage is a failed utility leg, a properly connected generator can restore power to the affected circuits while waiting for the utility or electrician. If the cause is an internal panel or neutral fault, do not use the panel at all until the fault is repaired — the fault may still be present and a generator doesn't resolve it. If you have a standby generator with an automatic transfer switch, confirm it's operating properly and note whether it's able to supply both legs — a 240V generator supplies both L1 and L2, which would restore everything; a 120V generator only supplies one leg.
Key Takeaways
- Half-house power loss is a service-level event — above individual breakers. Two causes: a lost hot leg (less dangerous, circuits dead but stable voltage) or a failed neutral (emergency, destructive overvoltage on one leg).
- The single most important observation: are any lights getting brighter while others go dark? If yes: turn off the main breaker immediately and call your utility and a licensed electrician. This is a neutral failure.
- If lights are clean half-and-half with no brightening and this followed a storm: call your utility's outage line. Service-drop leg failures are common after high winds and are their repair responsibility.
- Do not open the panel cover, touch service conductors, or attempt to tighten any connections. Service-entry conductors are always energized at utility voltage even with all circuit breakers off.
- Unplug sensitive electronics and stop running 240V appliances if there's any question about voltage stability. The cost of a service call is much less than replacing damaged appliances from a neutral float event.