Quick answer
A ground fault is an unintended electrical path between a live conductor and the ground or a grounded surface, so current leaves its normal circuit and flows through metal, water or a person instead.
CPSC notes most ground faults happen when equipment is damaged or defective and live parts are no longer covered 1. The danger is shock, burns and sometimes fire.
Quick facts
The key facts about Ground Fault, with sources:
Ground fault in plain words
Electricity is meant to travel out on the hot wire and back on the neutral. In a ground fault, some or all of it takes a shortcut to ground. That shortcut can be a metal appliance case, a water pipe, wet soil or your body.
CPSC defines it as an unintentional electrical path between a power source and a grounded surface. If your body becomes that path, you can be burned, shocked or killed 1.
Key takeaways
- A ground fault is current leaking from a hot wire to ground 1.
- It is most dangerous near water and outdoors, where a person is well grounded.
- Grounding gives fault current a safe path so the breaker trips.
- A GFCI catches leaks far too small for a breaker, as low as 0.006 amps 1.
- A tingle from a faucet, tub or appliance is a warning sign; stop and call an electrician.
The path of a ground fault
- Damaged insulation lets the hot wire touch a metal case
- → the case is now live
- → a person touches the case and a grounded faucet
- → current flows through the body to ground
- → a ground-fault circuit interrupter (GFCI) sees current missing from the neutral and trips
How a ground fault behaves
What happens next depends on the path. If the metal case is bonded to the equipment grounding conductor, a large current rushes back to the panel. The breaker trips. That is the job of grounding.
If there is no good ground path, the case can stay live with nothing tripping. The fault waits until a person completes the path. That current may be only a few hundredths of an amp, far below what trips a 15-amp breaker, yet enough to stop a heart 2.
OSHA lists ground faults with short circuits and overloads as causes of overcurrent. It is clear that a fault, such as a short circuit or ground fault, is not an overload 3.
- If Case is grounded and fault current is large
- Then Breaker trips; power off
- If Case is not grounded, no one touching
- Then Nothing trips; case stays live (hidden danger)
- If Leak through a person, on a GFCI circuit
- Then GFCI trips at about 6 mA
- If Leak through a person, no GFCI
- Then Breaker may never trip; shock continues
Common kinds of ground faults at home
| Kind | Typical cause | What you might notice |
|---|---|---|
| Appliance case fault | Worn wire touches a metal housing | Tingle when touching the appliance; GFCI trips |
| Water intrusion | Rain or flooding in an outdoor box or fixture | GFCI trips after storms |
| Damaged cord | Cut or crushed extension cord on wet ground | Trips when the cord is in use |
| Cable damage | Nail or screw through a cable in a wall | Breaker trips right after hanging something |
| Motor or heating element fault | Insulation breakdown in a pump or water heater | Repeated trips when it runs |
Example: why a breaker misses a shock
Thresholds from the Merck Manual and CPSC compared with a common breaker size.
| Device or effect | Current | Source |
|---|---|---|
| GFCI trip point | 0.006 A (6 mA) | 1 |
| AC let-go current, 70 kg adult | About 0.015 A (15 mA) | 2 |
| Can cause ventricular fibrillation (AC, across chest) | 0.06 to 0.1 A (60 to 100 mA) | 2 |
| Typical bedroom circuit breaker | 15 A | Common rating |
A shock that can kill uses less than one hundredth of the current needed to trip a 15-amp breaker. Only a GFCI reacts at that level.
Where ground faults happen most
- Bathrooms and kitchens, near sinks and tubs
- Outdoors: yards, pools, spas and hot tubs
- Garages and unfinished basements with concrete floors
- Laundry rooms and utility sinks
- Anywhere power tools or yard tools are used; CPSC suggests portable GFCIs there 1
Why knowing about ground faults helps
A tripped GFCI is a ground-fault alarm. It does not mean the device is broken. It means current went somewhere it should not.
Water lowers skin resistance, so codes put GFCIs where people and water meet. CPSC credits GFCIs with a large part in reducing electrocutions 1.
Limits of ground-fault protection
GFCIs only see leaks to ground. A person touching hot and neutral at the same time, while standing on something insulated, can be shocked with no ground fault at all.
Grounding also has limits. It only helps if the ground path is intact from the device back to the panel. Old two-prong wiring often has none. Adding a three-prong outlet without a ground wire creates false confidence.
Learn more in our guide to grounding and bonding.
What drives the cost of fixing a ground fault
We do not list prices. The cost depends on what is found. A faulty appliance may just need repair or replacement. A wet outdoor box may need a weather-rated cover. A cable damaged inside a wall may need opening the wall. Missing grounds across a whole house can point to rewiring.
Diagnosis time, access, permit rules and the number of circuits all change the bill. See cost guides for what drives electrical pricing.
How an electrician tracks down a ground fault
- Ask what tripped, when, and what was running.
- Unplug loads and isolate the circuit to see if the fault is in wiring or an appliance.
- Test insulation resistance and the ground path with proper instruments.
- Inspect outdoor boxes, covers and fixtures for water.
- Repair or replace the faulty part, then confirm the GFCI holds and tests correctly.
Preventing ground faults
Ground fault warning signs
- A tingle or buzz from a faucet, tub, appliance or metal fixture.
- A GFCI that trips again right after reset.
- A breaker that trips when it rains.
- Scorch marks or a burning smell at an outlet.
- A pool, spa or hot tub that feels "electric." Get everyone out without touching metal, and call for help.
A tingle is an emergency signal
If you feel even a mild shock from a fixture or appliance, stop using it. Do not touch a person who is being shocked; cut the power at the breaker or unplug first if it is safe. Call 911 for any injury, then a licensed electrician. Never open panels or boxes yourself.
Rules that address ground faults
NEC 2023 210.8. Requires GFCI protection for personnel in dwelling bathrooms, kitchens, garages, outdoors, basements, laundry areas 1 and areas with sinks 4.
NEC grounding rules. The NEC (NFPA 70) sets how equipment is grounded so fault current can trip the breaker 5.
OSHA 29 CFR 1910.399. In workplaces, OSHA defines a GFCI as a device that de-energizes a circuit within a set time when current to ground exceeds a set value 3.
Local adoption decides which NEC edition applies. Existing homes usually keep the protection they were built with until work triggers an update.
Ground fault vs short circuit vs overload
| Event | Current path | Usual protection |
|---|---|---|
| Ground fault | Hot to ground or grounded metal | GFCI for people; grounding + breaker for equipment |
| Short circuit | Hot to neutral or hot to hot, bypassing the load | Breaker or fuse trips fast |
| Overload | Normal path, too much load | Breaker trips after a delay |
| Arc fault | Current jumping a gap | AFCI |
Ground fault myths
- Myth A ground fault always trips the breaker.
- Reality Small leaks through a person often do not. Only a GFCI reacts at 6 mA 1.
- Myth A three-prong outlet means the outlet is grounded.
- Reality Not always. Older homes sometimes have three-prong outlets with no ground wire behind them.
- Myth Ground faults only happen outdoors.
- Reality Bathrooms, kitchens and laundry areas see them too.
- Myth Rubber-soled shoes make you safe.
- Reality They may reduce current, but wet skin or touching a grounded faucet can still complete the path.
Local code and climate
GFCI coverage depends on the NEC edition your state adopted 6. Wet climates and flood-prone areas see more outdoor ground faults, so in-use covers and protected outdoor outlets matter more there. Check your edition before any outdoor or kitchen project.
What to do about ground faults
If you have outlets near water without GFCI protection, or a GFCI that keeps tripping, have it checked. Both are common in older homes.
Next step: take the free electrical safety check, then book electrical repair for any outlet that trips or shocks.
Ground fault vs grounding
A ground fault is the problem: current escaping to ground. Grounding is part of the cure: a planned path that carries fault current back so the breaker trips.
Questions about Ground Fault
What causes a ground fault?
Most ground faults come from damaged or worn insulation, water getting into outlets or fixtures, cut cords, or nails and screws hitting cables. CPSC notes they most often occur when equipment is damaged or defective, so live parts are no longer covered.
Is a ground fault dangerous?
Yes. If your body becomes the path to ground, you can be burned, shocked or killed. The current needed to harm you is tiny compared with what trips a normal breaker. That is why GFCIs are required near water.
What is the difference between a ground fault and a short circuit?
In a short circuit, current jumps from hot to neutral or hot to hot, usually with a huge surge that trips the breaker. In a ground fault, current leaks from hot to ground. A large ground fault trips the breaker; a small one through a person needs a GFCI.
How do I know if I have a ground fault?
Signs include a GFCI that trips repeatedly, a breaker that trips in rain, or a tingle from an appliance, faucet or tub. Reset a GFCI once. If it trips again, or anyone felt a shock, stop using the circuit and call an electrician.
Can a ground fault cause a fire?
Yes, a ground fault can. Current flowing through an unplanned path can heat materials. CPSC says GFCIs can prevent some electrical fires by stopping ground-fault current. But fire from arcing is mainly addressed by AFCIs.
Does a ground fault mean my wiring is bad?
Not always. Often the fault is in one appliance or cord. Unplug everything on the circuit and see if the GFCI holds. If it trips with nothing plugged in, the fault is likely in the wiring or a fixture, and an electrician should find it.
Can I reset a GFCI after a ground fault?
You can press RESET once. If it holds, use the outlet normally but watch for repeat trips. If it trips again right away, leave it off and call an electrician. Never replace a tripping GFCI with a plain outlet.
What protects against ground faults?
Two things. Grounding gives fault current a low-resistance path so the breaker trips fast. A GFCI watches for small leaks, as low as 6 milliamps, and cuts power before a shock becomes deadly. Homes need both.
Is a ground fault the same as an electrical short?
People often use "short" for both, but they differ. A ground fault sends current to ground or grounded metal. A short circuit connects hot to neutral or hot to hot.
Both are faults, not overloads, and OSHA lists both as causes of overcurrent. The protection you need differs, so the term matters when an electrician explains a repair.
Can a ground fault happen with the switch off?
Yes, in some cases. A switch usually opens only the hot wire to a light or device.
If wiring before the switch is damaged, or a fixture is miswired, a metal part can stay live.
That is one reason never to treat a fixture as dead just because its switch is off. Electricians test before they touch.
Why does my outdoor outlet trip when it rains?
Water is likely getting into the outlet, box or a plugged-in cord, creating a ground fault. The GFCI is doing its job. Have an electrician check the cover, seals and box, and use a weather-rated in-use cover.
Sources
- U.S. Consumer Product Safety Commission, GFCI Fact Sheet (Publication 099), retrieved .
- Merck Manual Professional Version, Electrical Injuries, retrieved .
- OSHA, 29 CFR 1910.399 Definitions applicable to Subpart S (Electrical), retrieved .
- Leviton Captain Code 2023, NEC 2023 210.8(A) GFCI requirements (quotes NFPA 70, 2023 edition), retrieved .
- NFPA, NFPA 70 National Electrical Code standard development page, retrieved .
- NFPA, NEC enforcement maps, 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: Definition and GFCI behavior from CPSC Publication 099; overcurrent and GFCI definitions from OSHA 1910.399; shock thresholds from the Merck Manual; NEC 2023 210.8 via Leviton. Read 10 October 2026.
Suggest a correction. We fix errors and say what changed.