1. Observe
What tripped?
- Breaker handle moved.
- GFCI or AFCI button popped.
- One outlet, room, or circuit lost power.
Stop line.
Warm is tolerable. Hot-to-touch, discolored, buzzing, arcing, or repeatedly tripping equipment is a fault signal. CPSC guidance treats these as warning signs, not normal behavior.
How to use this page.
Start with the symptom table, then jump to the device comparison or the troubleshooting playbooks. The load strip and worksheet are the parts most people print and keep by the panel.
Quick reference
Highest-frequency homeowner lookups
| Symptom | Likely cause | Safest first move | Stop / call |
|---|---|---|---|
| One breaker trips when a heater, dryer, or fryer starts | Overload or a failing appliance | Unplug the load, reset once, then move the load or reduce what is running | If it trips again, do not keep resetting it |
| A whole room or run of outlets is dead | Tripped breaker, tripped GFCI upstream, or failed receptacle | Check the panel and any GFCI receptacles on that circuit | If you must remove the panel cover, stop |
| GFCI will not reset | Wiring fault, failed device, or the downstream load still has a fault | Unplug the loads and test again | Persistent failure needs an electrician |
| Plug, receptacle, or faceplate feels hot | Loose connection, worn receptacle, or overloaded cord | Unplug and stop using that outlet immediately | If discolored or melting, treat as urgent |
| Lights flicker with wind | Service-entrance or utility-side connection problem | Do not touch the service equipment; call the utility | Utility-side issue, not a homeowner repair |
| Outdoor outlet dead after rain | Moisture, weatherproof cover problem, or GFCI trip | Dry conditions first, then check the GFCI and cover | If moisture entered the box, stop and inspect professionally |
| Extension cord is warm or buried under a rug | Overload or damaged routing | Unplug it and reroute; cords are temporary only | Do not keep using it as permanent wiring |
| One appliance keeps blowing the same breaker | Appliance defect or too much load on that circuit | Test the appliance on a different circuit, with the load reduced | If it still trips, the appliance or wiring needs service |
Signature visual
Breaker trip diagnostic tree
2. Isolate
Unplug obvious loads
- Space heater, hair dryer, fryer, vacuum.
- Any warm, loose, or damaged cord.
- Anything on a power strip or extension cord.
3. Reset once
Restore power carefully
- Breaker: OFF, then ON.
- GFCI/AFCI: TEST, then RESET only if the fault is gone.
- If it trips again, stop.
4. Escalate
Call a pro when needed
- Repeated trips.
- Hot, buzzing, or scorched devices.
- Service-drop or panel warning signs.
Watts = volts x amps
At 120 V, a 1,200 W appliance draws about 10 A.
15 A branch
CPSC examples use about 1,500 W as the practical ceiling.
20 A branch
CPSC examples use about 2,000 W as the practical ceiling.
Fundamentals
Mental model: what the home electrical system is doing
| Term | Definition | Concrete example | Gotcha |
|---|---|---|---|
| Voltage | Electrical pressure that pushes current through a circuit. | U.S. residential outlets are typically 110-120 V, with many homes also having 240 V for large appliances. | Different countries use different voltages and plugs; do not assume compatibility. |
| Current | Amount of electricity flowing, measured in amps. | A 1,500 W heater at 120 V draws about 12.5 A. | Too much current overheats wires, cords, plugs, and receptacles. |
| Power | Rate of electrical use, measured in watts. | Watts = volts x amps; a 1,300 W hair dryer plus a 150 W fan totals 1,450 W. | Watts are what you add up on the same branch circuit. |
| Branch circuit | The wiring run fed from the panel to lights, receptacles, and loads in a zone of the home. | Kitchen receptacles may share one branch circuit; a garage outlet can be on another. | A dead outlet may still be downstream of a tripped GFCI or breaker elsewhere. |
| Neutral | The return conductor for normal current. | In a standard U.S. 120 V outlet, one vertical slot is hot and the other is neutral. | Neutral is not a "safe" wire; it can still carry current. |
| Ground | Safety path that helps clear faults and reduces shock risk. | Three-prong plugs use the ground pin to protect the metal case of a device during a fault. | A GFCI can protect you even when a receptacle is ungrounded. |
| Service equipment | The path that brings utility power into the home panel. | CPSC describes typical service drop / entrance cable systems as 120/240 V low-voltage service. | If the issue appears on the utility side, do not open the panel or tinker with the drop. |
| Dedicated circuit | A circuit reserved for one major load. | Many electric dryers, dishwashers, and microwaves are best on their own circuit. | Shared circuits are where nuisance trips usually come from. |
Practical rule: if the math, the label, and the cord rating do not agree, trust the smallest safe rating and stop there.
Working knowledge
Protection devices: what each one does
| Device | Definition | Use it when | Does not do |
|---|---|---|---|
| Standard breaker | Overcurrent protection that opens the circuit when current exceeds the safe rating. | You need general overload and short-circuit protection for a branch circuit. | It does not protect against shock from ground faults. |
| GFCI receptacle | Outlet device that trips when current leaves the intended path. | Bathrooms, kitchens, garages, unfinished basements, outdoor outlets, laundry/wet-sink areas. | It does not reduce load or stop a cord overload. |
| GFCI breaker | A breaker with built-in ground-fault protection for the whole branch circuit. | You want protection for all outlets and lights downstream. | It still needs correct wiring and monthly testing. |
| AFCI breaker | Breaker that senses abnormal arcing in damaged wiring or connections. | Bedrooms and other dwelling areas where arc-fault protection is specified by the local code edition. | It is not a substitute for GFCI in wet locations. |
| Dual-function breaker | Breaker combining GFCI and AFCI behavior in one device. | You need both forms of protection on the same circuit. | It does not make an overloaded circuit safe. |
| Surge protector | Device for transient voltage spikes, usually from lightning or switching events. | Electronics with sensitive power supplies or data ports. | It does not protect against overloads or shock hazards. |
| Power strip | Convenience outlet multiplier, not a wiring upgrade. | Low-power devices with clear total wattage under the strip rating. | It does not turn one wall outlet into a heater circuit. |
Decision rule: use GFCI for shock-risk locations, AFCI for arc-risk branch circuits, and a dedicated circuit for big fixed loads. None of them solve overload math.
Load math
How to estimate appliance load safely
| Rule / example | Definition | Concrete example | Gotcha |
|---|---|---|---|
| Watts = volts x amps | Convert a device label into current or power budget. | 1,200 W at 120 V is 10 A. | Do not guess from size or heat output; read the nameplate. |
| 15 A branch circuit | CPSC's practical example budget for a 15 A branch is about 1,500 W. | 1,300 W hair dryer + 150 W fan = 1,450 W, which is already close. | One more appliance can push it over. |
| 20 A branch circuit | CPSC's practical example budget for a 20 A branch is about 2,000 W. | 1,200 W vacuum + 600 W portable fan = 1,800 W, which fits better. | Continuous loads need more headroom than a momentary burst. |
| Continuous load | A load expected to run for 3 hours or more should be sized to no more than 80% of a breaker rating unless the breaker is marked for 100% continuous use. | A 15 A breaker is a poor fit for a 12.5 A heater running all evening. | 80% is a breaker-rating rule, not a magic safety blanket. |
| Space heater rule | High-wattage heat belongs on its own wall outlet, not on a strip or small cord. | CPSC says if you must use an extension cord with a heater, use a heavier cord and keep the run temporary. | Best answer is usually to plug directly into the wall. |
| Cord gauge | Lower gauge number means thicker wire and more current capacity. | CPSC warns older No. 18 gauge cords can overheat at 15 or 20 A; No. 16 is heavier. | Do not assume two cords with the same plug shape are equally safe. |
| Outdoor load | Wet-area and outdoor work should use GFCI protection and weather-rated cords or covers. | A lawn tool or pool pump should not be fed through a thin indoor cord. | Indoor cords are not built for moisture or abrasion. |
| Appliance examples | Use the nameplate watts on the device, not a generic guess. | CPSC examples: hair dryer 1,300 W, portable fan 150 W, vacuum 1,200 W, portable heater 1,400 W, deep fat fryer 1,000 W. | Two modest loads can exceed one circuit faster than people expect. |
Cords and strips
Extension cords, power strips, and what they are for
| Rule | Definition | Concrete example | When not to use it |
|---|---|---|---|
| Temporary only | Extension cords are for short-term use, not as permanent wiring. | Running a fan across the room for a weekend is acceptable; feeding a fridge for months is not. | Do not use them to replace missing outlets. |
| Keep it visible | A cord should not be buried where heat and damage are hidden. | CPSC says not to run cords under carpets, through doorways, or under furniture. | Never tape over a damaged section and hope for the best. |
| Outdoor rated | Outdoor cords and covers are built for moisture and mechanical abuse. | Use an outdoor-marked cord for patio lights or garden tools. | Indoor cords can fail outdoors even if they look fine at first. |
| Right gauge | Heavier wire handles more load with less heat. | CPSC specifically warns against older No. 18 gauge cords for 15-20 A loads; No. 16 gauge is heavier. | Do not assume a longer cord can carry the same current as a short one. |
| Hot plug = warning | Heat at the plug, socket, or whole cord means overload or a failing connection. | If a cord or receptacle is hot-to-touch, unplug and replace or inspect it. | Do not keep touching it to see whether it cools down. |
| Heater rule | Space heaters and other high-wattage appliances should go directly to a wall outlet when possible. | Portable heaters are the classic overload source on weak cords and strips. | Do not plug a heater into a power strip. |
| One outlet, one job | Some outlets are simply too busy for the loads being asked of them. | Kitchen counters or garage tool outlets often need a better circuit plan. | Stop stacking strips and splitters. |
| Test and inspect | Damaged cords and loose plugs are fire hazards, not cosmetic defects. | CPSC says to replace damaged extension cords and look for damaged insulation, hot plugs, or hot sockets. | Do not keep using a cord with cracked insulation or bent blades. |
Panel literacy
What the panel labels and breakers tell you
| Panel item | Definition | Concrete example | Gotcha |
|---|---|---|---|
| Panel label | The map of which breaker feeds which part of the home. | CPSC says the panel should contain a label or tag with an inspection date and initials. | If the label is missing or wrong, make a new one before you forget the circuit names. |
| Main disconnect | Device that turns off power to the home panel. | On many homes, the main breaker is in the service equipment or at the panel. | Do not open service equipment you do not understand. |
| Branch breaker | Breaker that protects one circuit run. | A 15 A or 20 A branch breaker is the one you reset when a room loses power. | Putting in a larger breaker to stop nuisance trips can overheat wiring. |
| Trip indication | Many breakers trip by moving to an intermediate position or fully to OFF. | CPSC describes both styles and says to reset by moving to OFF and then ON when the fault is gone. | If you cannot tell whether a breaker tripped, inspect it in good light. |
| Subpanel | A secondary panel that feeds another part of the home or outbuilding. | A garage or basement may have its own subpanel. | Do not assume a dead outlet is on the main panel just because the room is upstairs. |
| Aluminum wiring | Older branch wiring that can loosen at receptacles and switches. | CPSC warns those connections can loosen during use, lose good contact, and overheat. | Repair is for a qualified electrician, not a quick homeowner tighten-up. |
| Back-wired or push-in connections | Some receptacles use push-in connections that may loosen over time. | CPSC advises checking faceplates for overheating where back wire push-in connections exist. | Loose connections are a fire warning even if the outlet still works. |
| Panel cover | The metal or dead-front cover that protects energized parts. | CPSC explicitly says not to remove the service-panel cover yourself. | If the cover has to come off, the job has crossed the homeowner line. |
Troubleshooting
Playbooks for the most common home problems
| Problem | What it usually means | Safe homeowner move | Call / stop when |
|---|---|---|---|
| Breaker trips immediately when a device starts | Short, fault, or a load too large for the circuit. | Unplug the device, try once with other loads removed. | If it trips again, stop and treat the device or circuit as faulty. |
| Breaker trips after a few minutes | Overload heating up the breaker or conductor. | Reduce the total watts on that circuit. | If the same appliance keeps doing it, the appliance may be the fault. |
| GFCI outlet upstream of dead receptacles | Many outlets can be downstream of one protected receptacle. | Find and reset the tripped GFCI. | If it will not reset with all loads unplugged, get help. |
| Hot plug or hot receptacle | Loose connection or overloaded cord. | Unplug immediately and let it cool. | Any discoloration, melting, or repeated warmth needs service. |
| Lights flicker when wind blows | Potential service-drop or connection issue on the utility side. | Do not touch the service equipment; report it. | Utility or licensed electrician territory, not DIY. |
| Outdoor outlet stopped working after rain | Moisture entered the box or the GFCI tripped. | Dry it out, check the weatherproof cover, and test the GFCI. | If water is in the box or the outlet is damaged, stop. |
| One switch or receptacle does nothing | Faulty device, loose conductor, or upstream issue. | Check the breaker and any upstream GFCI before assuming the device is dead. | If the faceplate is hot or arcing occurs, stop immediately. |
| Repeated tripping on a space heater | The circuit is too small for the heater or there is another load on it. | Move the heater to a different circuit or reduce the load. | If the heater trips multiple circuits, the heater itself may be defective. |
Anti-patterns
Common mistakes that turn a nuisance into a hazard
| Mistake | Why it is wrong | Better move |
|---|---|---|
| Installing a bigger breaker to stop trips | The wire is the limit, not just the breaker handle. | Find the overload or fault and correct it. |
| Using extension cords as permanent wiring | CPSC says cords are temporary only and can overheat. | Add an outlet or fix the circuit layout. |
| Running cords under rugs or through doorways | Heat and abrasion are hidden until the damage is already there. | Route cords openly and replace with proper wiring when needed. |
| Assuming GFCI means grounded | GFCI protects against shock; it does not magically add a ground. | Test receptacles with the right expectations. |
| Plugging a heater into a strip or small cord | High-wattage heat plus extra resistance equals a fire risk. | Use a direct wall outlet or a dedicated circuit. |
| Ignoring a warm faceplate or plug | Heat is the warning sign before failure. | Unplug, stop using it, and investigate. |
| Working live in the panel | The cover hides energized parts that can kill you. | Call an electrician for anything beyond a simple breaker reset. |
| Trusting an unlabeled panel | Guessing which breaker feeds which room wastes time and creates mistakes. | Map and label circuits before an outage. |
Printable worksheet
Circuit map you can keep by the panel
| Breaker # | Area / room | Typical loads | GFCI / AFCI | Notes |
|---|---|---|---|---|
| 1 | Kitchen counters | Toaster, coffee maker, blender | GFCI | Keep total watts below the circuit limit. |
| 2 | Bathroom | Hair dryer, shaver, nightlight | GFCI | Hair dryer is often the load that trips things. |
| 3 | Garage / workshop | Vacuum, shop tool, battery charger | GFCI | Outdoor tools and wet conditions raise the stakes. |
| 4 | Bedroom 1 | Lamps, chargers, fan | AFCI | Good place to test AFCI monthly. |
| 5 | Bedroom 2 | Lamps, chargers, heater? | AFCI | Do not add a space heater without checking load. |
| 6 | Laundry / utility | Washer, dehumidifier, iron | GFCI / AFCI | Wet location and motor load both matter. |
| 7 | Living room | TV, console, lamp, laptop | AFCI | Easy to overfill with power strips. |
| 8 | Outdoor receptacles | Holiday lights, garden tools | GFCI | Weatherproof cover should close with nothing plugged in. |
Decision aid
What to use when
| If the goal is... | Use... | Example |
|---|---|---|
| Shock protection near water | GFCI | Bathroom vanity outlet or outdoor receptacle. |
| Fire protection from damaged wiring | AFCI | Bedroom or living-area branch circuit. |
| Both shock and arc-fault protection | Dual-function breaker | A remodeled circuit that needs both protections in one device. |
| A large appliance that runs for hours | Dedicated circuit | Space heater substitute, electric dryer, or freezer circuit. |
| A small temporary need | Short, properly rated extension cord | A lamp or fan for a weekend, not permanent wiring. |
| Transient voltage spikes | Surge protector | Computer, TV, router, or appliance with electronics. |
Related
Other pages in this repo that fit the same cluster
Primary sources
Verification targets used for this page
- CPSC GFCI Fact Sheet for monthly testing, receptacle/breaker types, and reset behavior.
- CPSC Home Electrical Safety Checklist for GFCI/AFCI testing, room coverage, panel labeling, and wet-area guidance.
- CPSC Household Extension Cords Can Cause Fires for temporary-use guidance, overheating, and routing rules.
- CPSC Home Wiring Hazards for breaker trips, warm receptacles, flickering from service connections, and aluminum wiring.
- DOE Electricity 101 for U.S. 110-120 V / 60 Hz, hot-neutral-ground, and general electrical basics.
- UL breaker application guide for the 80% continuous-load rule.
- NFPA AFCI overview for arc-fault purpose and location context.