Quick answer
An open neutral is a break or failed connection in the neutral conductor, the return path for current, which lets voltage on a home's two 120-volt legs swing apart so some circuits get too much voltage and others too little.
A loose neutral is the early stage: the connection has become resistive but not fully broken 1. Either one can damage electronics and appliances and, in some cases, start fires 1.
Quick facts
The key facts about Open Neutral, with sources:
- Normal home service
- 120/240 V split phase; each leg about 120 V to neutral 1
- Classic sign
- Some lights brighten while others dim at the same time 1
- Example of a shift
- 119/121 V becoming 105/135 V, still about 240 V in total 1
- Worst case
- Voltages approaching twice nominal on lightly loaded circuits 1
- ANSI C84.1 Range A service voltage
- 114 to 126 V on a 120 V base 2
- Who to call
- Your electric utility (the fault can be on its side of the meter) and a licensed electrician 1
Key takeaways
- An open neutral breaks the return path shared by your home's two 120-volt legs.
- Voltage then splits unevenly: one side drops while the other rises 1.
- Lights getting brighter and dimmer at the same time is a strong sign 1.
- It can destroy appliances and electronics and may start fires 1.
- Unplug sensitive devices and call your utility right away; then an electrician.
If you suspect an open neutral now
Act now, but do not touch equipment
Turn off or unplug electronics and large appliances. Call your electric utility's emergency line, since a loose neutral can be on their side of the meter. Do not open the meter, panel or outlets. If you smell burning or see smoke or sparks, leave the house and call 911.
What the neutral does
Most U.S. homes get 120/240-volt split-phase service. The utility transformer has a center tap, and that center tap is the neutral. It is grounded at the transformer and again at the meter base or panel 1.
Two hot legs each measure about 120 V to the neutral, and 240 V to each other 1. Every 120-volt circuit uses one hot leg and the shared neutral. The neutral carries the difference between the two legs' loads back to the transformer.
When the neutral breaks, that difference has nowhere to go. The two legs end up in series across 240 V, and the voltage on each side is set by how much load each side has.
Solid neutral
- Each leg holds about 120 V to neutral
- Neutral carries the load difference home
- Unequal loads cause no voltage swing
Open neutral
- Legs end up in series across 240 V
- The lighter-loaded leg rises, the heavier one falls
- Swing grows as loads become more unequal
Source: [1]
How an open neutral shifts voltage
Picture a seesaw. With a solid neutral, both sides sit at 120 V no matter the load. With the neutral open, the side with more load (lower resistance) gets less voltage, and the side with less load gets more. The two still add up to about 240 V 1.
The more unbalanced the loads, the bigger the swing. In a full open-neutral case, voltage on the lightly loaded side can approach twice nominal 1. A 120 V TV can suddenly see far more than it was built for.
A big 240-volt load like a range or heater does not use the neutral, so it can mask the problem while it runs 1. That is one reason the symptoms come and go.
Where the neutral can fail
| Location | Who usually owns it | Typical cause |
|---|---|---|
| Utility transformer or overhead drop | Utility | Weather, corrosion, damaged connectors |
| Underground service lateral | Utility or owner (varies by utility) | Nicked conductor that corrodes over time 1 |
| Meter base neutral terminal | Varies; often owner equipment | Loose or corroded lug |
| Panel neutral bar | Owner | Loose service neutral or bar connection |
| Branch circuit neutral | Owner | Loose splice or device; a shared (multiwire) neutral opening |
Example: reading the symptoms
Patterns that point toward a neutral problem, compared with other causes. Based on the Power Monitors white paper and ANSI voltage ranges 1 2.
| What you notice | Likely meaning | Who to call |
|---|---|---|
| Some lights brighten while others dim at the same moment | Strong sign of a loose or open service neutral 1 | Utility first, now |
| All lights dim together, neighbors too | Grid low voltage or utility brownout | Utility |
| Lights dim briefly when the AC starts | Normal motor-start sag or circuit voltage drop | Electrician if severe |
| Bulbs burn out often on one side of the house | Possible high voltage on one leg | Utility and electrician |
| Several electronics fail at once, no storm | Possible open neutral rather than a surge | Utility and electrician |
Power Monitors also notes that a defective voltage regulator or big load changes can cause light changes, so measurement by a qualified person is the way to confirm 1.
Where you notice it in the house
- Lights on one circuit get very bright while others go dim.
- Lights change brightness when a large 120-volt appliance switches on or off.
- Electronics, chargers and appliances with control boards fail or behave oddly.
- Motors hum or run hot on the low side.
- Problems ease when an electric range or dryer runs, then return 1.
Why recognizing it early matters
A loose neutral often gets worse over time. Power Monitors explains that heat from current flow speeds oxidation at a bad connection, which raises resistance further 1. Catching it while it is only loose can save every device in the house.
The pattern also points to who should come out first. A loose neutral can sit on the utility side of the meter 1, and that part is the utility's to fix.
What does not protect you
Surge protectors are built for short spikes. An open neutral can hold high voltage for minutes or hours, which can overwhelm or destroy a surge protector rather than be stopped by it.
Breakers do not trip on an open neutral either. Current on each leg may be normal or even lower; it is the voltage that is wrong.
GFCIs may or may not react. Some electronics shut down from low voltage while others on the high side keep running until they fail.
What drives repair costs
We do not list prices. If the fault is on the utility's side, the utility repairs its equipment; ask about its process for damage claims.
If it is at your meter base, panel or wiring, the electrician's time, parts and any permit set the cost.
Corroded service equipment may need replacing, which can lead to a panel or service upgrade.
Damaged appliances and electronics are often the larger cost. Homeowners insurance may cover some of it; check your policy.
How an open neutral gets found and fixed
- You report the symptoms; the utility checks voltage at the meter and their connections.
- If the utility side is sound, a licensed electrician measures each leg to neutral at the panel under load.
- The electrician inspects the service neutral, meter base and neutral bar for loose or corroded terminals.
- Branch circuits with symptoms are checked, including shared neutrals on multiwire circuits.
- Connections are repaired or equipment replaced; voltages are tested balanced under load.
- Damaged devices are checked before they go back into service.
Reducing the risk
- Have service connections inspected when you buy an older home.
- Report damaged overhead drops, leaning meter bases or corroded meter boxes to the utility.
- Have an electrician check the panel during any major remodel or panel work.
- Mark underground service routes before digging; a nicked neutral can corrode later 1.
- Treat flickering patterns as information, not a nuisance.
Warning signs
- Lights brightening and dimming at the same time on different circuits 1.
- Appliances or electronics failing with no storm.
- Buzzing or burning smell at the meter or panel.
- Tingling from metal fixtures or plumbing.
- Voltage readings far outside 114 to 126 V on one leg, measured by a qualified person 2.
Open neutral vs power surge
A surge is a spike lasting millionths to thousandths of a second. An open neutral holds the wrong voltage until it is fixed. Surge protectors help with the first, not the second.
Standards and rules that apply
ANSI C84.1 (voltage ratings, 60 Hz). The national standard for service and utilization voltage. Range A service voltage is ±5% of nominal; voltages outside it should be infrequent, and sustained Range B conditions call for correction within a reasonable time 2. Utilities apply it through their tariffs; state utility commissions oversee service quality.
NEC (NFPA 70). Sets how the grounded (neutral) conductor is installed, identified and connected in buildings 5. Your state's adopted edition applies to new and altered wiring; existing installations are judged under local rules.
OSHA 29 CFR 1910.399. Defines the grounded conductor as a system or circuit conductor that is intentionally grounded, the role the neutral plays 4.
Work on service equipment requires a licensed electrician and, in most places, utility coordination and a permit.
Open neutral vs similar problems
| Problem | Voltage pattern | Duration | First call |
|---|---|---|---|
| Open neutral | One leg high, the other low | Until repaired | Utility |
| Brownout | Everything low | Minutes to hours | Utility |
| Power surge | Brief spike | Microseconds to milliseconds | None, or electrician if damage |
| Ground fault | Normal voltage, current leaking to ground | Until fixed | Electrician |
Open neutral myths
- Myth Flickering lights are just old bulbs.
- Reality Opposite brightening and dimming is a strong sign of a neutral problem 1.
- Myth A breaker would trip if something were wrong.
- Reality Breakers react to current, not voltage; an open neutral may not trip anything.
- Myth A surge protector will save my electronics.
- Reality Long overvoltage can destroy surge protectors along with the devices.
- Myth It is always my wiring.
- Reality The break can be on the utility side of the meter 1, so report it to them as well as an electrician.
Utility tariffs and local rules
Where the utility's responsibility ends, at the drop, the meter or the service lateral, depends on your utility's tariff.
State utility commissions set service voltage rules; A 2002 California Public Utilities Commission finding, for example, described utility Rule 2 as requiring most service voltage at the meter to fall between 114 and 120 V, with limited exceptions 3; check your utility's current tariff. Electrician licensing for service work is set by each state.
What to do next
If you see the bright-and-dim pattern, call the utility now and unplug sensitive devices. If the utility finds nothing on their side, book an emergency electrician the same day.
If you only see occasional mild flicker, schedule an electrical inspection and mention it. Learn more about how grounding and the neutral work together in our grounding and bonding guide.
Questions about Open Neutral
What are the signs of an open neutral?
The classic sign is some lights getting brighter while others dim at the same moment. Others are electronics failing without a storm, appliances acting oddly, and symptoms that ease when an electric range or dryer runs. Call your utility right away if you see them.
Is an open neutral dangerous?
Yes. Voltage on one side of the house can rise far above 120 volts while the other side drops. That can destroy appliances and electronics and, in some cases, start fires. Treat it as urgent.
Who fixes an open neutral, the utility or an electrician?
Call the utility, since the break can be on their side: the transformer, drop or service lateral. If their equipment is fine, a licensed electrician checks the meter base, panel and wiring. Where responsibility ends depends on your utility's rules.
What is the difference between a loose neutral and an open neutral?
A loose neutral has a poor, resistive connection that partly works, causing smaller voltage swings that come and go. An open neutral is fully broken, causing larger swings that can approach twice normal voltage on lightly loaded circuits.
Why are some of my lights bright and others dim?
When the shared neutral is loose or open, the two 120-volt legs of your service stop holding equal voltage. One leg rises and the other falls. The pattern of bright and dim at the same time is a strong sign of a neutral problem.
Can an open neutral damage appliances?
Yes. Devices on the high-voltage side can be overstressed and fail, especially electronics and appliances with control boards. Motors on the low side can overheat. Unplug sensitive devices until the fault is fixed.
Will a breaker trip on an open neutral?
Usually not. Breakers respond to excess current, and an open neutral is a voltage problem. That is why it can go on for hours causing damage without anything tripping.
What causes an open neutral?
Common causes are loose or corroded connections at the transformer, drop, meter base or panel, weather damage, and underground conductors nicked during digging that corrode over time. Heat at a bad connection speeds oxidation, so it often worsens.
Can a surge protector protect against an open neutral?
Not reliably. Surge protectors handle brief spikes. An open neutral can hold high voltage for a long time, which can burn out the surge protector along with the devices. Unplugging and calling the utility is the right move.
What should I do while waiting for the utility?
Unplug electronics and turn off large appliances. Do not touch the meter, panel or outlets. If anything smells hot or you see smoke or sparks, leave the house and call 911.
Sources
- Power Monitors Inc., Identifying Loose Neutrals (white paper), retrieved .
- Pacific Gas and Electric Company, Voltage Tolerance Boundary (summary of ANSI C84.1), retrieved .
- California Public Utilities Commission, Interim Opinion on Emergency Voltage Reduction Measures (proposed decision, 2002), findings of fact, retrieved .
- OSHA, 29 CFR 1910.399 Definitions applicable to Subpart S, retrieved .
- NFPA, NFPA 70 National Electrical Code standard development page, retrieved .
Expert review
Written by the HyreElectrical Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Split-phase behavior, causes, symptoms and example voltages from the Power Monitors white paper; voltage ranges from PG&E's ANSI C84.1 summary and a CPUC decision; grounded-conductor definition from OSHA 1910.399. Read 10 October 2026. Held for review by a qualified electrical reviewer before indexing.
Suggest a correction. We fix errors and say what changed.