How do you know if your GFCI outlet is bad?

Ground fault circuit interrupter (GFCI) outlets are an important safety device found in bathrooms, kitchens, garages, and outdoor areas. They help prevent electrocution by quickly shutting off electricity when a ground fault is detected. However, like any electrical device, GFCIs can malfunction or wear out over time. Knowing the signs of a bad or failing GFCI outlet can help you identify and replace ones in need of repair.

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What is a GFCI outlet?

A GFCI outlet monitors electricity flowing in a circuit. If there is an imbalance, meaning electricity is escaping the wiring, the GFCI will trip and rapidly switch off power to that circuit. This helps halt the flow of electricity when it starts going somewhere it shouldn’t, like through water or a person.

A GFCI outlet is designed with special internal circuitry that can detect small differences in current flow between the hot and neutral wires in a circuit. This allows it to trip at milliamp levels, which is fast enough to prevent severe electrical shocks from occurring.

Standard outlets don’t have this same sensitivity and may allow dangerous amounts of electricity to flow through a person before tripping a regular circuit breaker. That’s why code requires the use of GFCI outlets in higher risk areas where water and electricity may come into contact.

Signs your GFCI outlet may be bad

Here are some of the most common signs that your GFCI outlet may be malfunctioning or worn out:

Frequent, unexplained tripping: If your GFCI keeps tripping even when nothing is wrong, it likely means the device itself is faulty. GFCIs are designed to allow small amounts of harmless current to pass through without tripping. If it’s tripping when not overloaded or shorted, the internal sensing circuitry is probably deteriorated.

No power: If the outlet doesn’t provide power at all no matter what you plug in, this likely indicates an internal wiring issue or complete failure of the GFCI device.
Not resetting when pressed: When a GFCI trips, you should be able to easily reset it by pressing the “Reset” button. If the button doesn’t pop back out when pressed or power isn’t restored, the device needs replacement.
Loose receptacle: If the outlet is poorly secured in the electrical box, this can create a potential shock hazard. Tight connections are important for safe, reliable power.

Scorch marks or melted plastic: Discoloration, deformities, or melting damage on the outlet or plugs can indicate overheating from an unsafe electrical load. This creates a fire risk and means the GFCI is not interrupting power properly when overloaded.
No lights on the outlet: Most GFCIs have indicator lights that illuminate when the outlet has power. If the lights don’t come on, it usually means the GFCI has malfunctioned or is not wired correctly.
Frequently blown fuses: If the circuit’s fuse keeps blowing when the GFCI outlet is used, it likely indicates a short circuit in the device. Damaged or faulty internal wiring can create shorts.

Buzzing, cracking, or sizzling: Unusual electrical noises from a GFCI are a warning sign of potential failure. This may be arcing or sparks inside.

How to test a GFCI outlet

To thoroughly test whether your GFCI outlet is working properly, follow these steps:

Plug a nightlight or lamp into the outlet and turn it on.

Press the “Test” button on the GFCI. The device should cut power and the light should turn off.
Press the “Reset” button. The light should turn back on again.
With the outlet reset and the light on, unplug the light and plug it into another nearby outlet that’s on the same circuit.

Press the “Test” button again. The light should lose power even though it’s no longer plugged into the GFCI.

If the GFCI doesn’t trip when the test button is pressed, or if the light doesn’t turn back on when reset, then the GFCI is faulty and should be replaced.

If the GFCI only cuts power to its own plugs and not the rest of the circuit when tested, this indicates it was wired incorrectly. The wiring will need to be corrected for full GFCI protection.

How a GFCI Works

To understand why a GFCI might fail, it helps to know a little bit about how they work. A GFCI monitors the flow of electricity on the hot and neutral wires supplying an outlet. Under normal conditions, the current on the neutral wire should be equal to the hot wire, meaning all the electricity that leaves the hot wire returns on the neutral.

But when there’s a ground fault, some of the current “leaks” off the hot and flows to ground through an alternate path instead of returning on the neutral. This imbalance of flow trips the GFCI and cuts power.

GFCIs are able to detect very small leaks in current, on the order of 4 to 6 milliamps. For comparison, it takes about 50 milliamps to give a serious shock. The small leak threshold prevents major shocks from occurring.

Inside the GFCI device, a small transformer constantly monitors the flow of electricity. When there’s an imbalance between hot and neutral of a few milliamps or more, it induces a voltage in the transformer circuitry. This voltage actuates a relay which quickly switches off power to the connected outlet.

When you press the “Reset” button, it resets the internal latch on the relay to restore power again. Pressing “Test” simulates a ground fault by diverting a small amount of current from hot to the ground wiring terminal, unbalancing the hot and neutral currents to trip the device.

Reasons Why a GFCI Outlet Can Fail

Based on how they operate, here are some of the most common reasons a GFCI outlet may fail and trip frequently:

Water damage: Moisture or water intrusion can corrode or degrade GFCI wiring and components. Bathrooms and outdoor areas expose outlets to humidity and leaks.
Electrical surges: Power surges from lightning strikes or faulty appliances on the circuit can burn out the sensitive electronics in a GFCI.
Damaged neutral wire: If the neutral wire connection is loose or broken, it will cause significant current imbalance even during normal operation.

Ground faults: Too many actual ground faults from faulty appliances or devices on the circuit can lead to excessive tripping and wear out components.
Overloaded circuit: When a circuit is overloaded with devices like hair dryers, the resulting heat and current draw can damage the GFCI sensing elements.
Old age: GFCIs can simply wear out from regular use over 10-20 years, leading to false tripping or failure to trip when needed.

Dangers of a Faulty GFCI

It’s important to replace or repair faulty GFCI outlets because they may no longer provide adequate protection from dangerous shocks. An outlet that trips when it shouldn’t or fails to trip at all poses risks including:

Electrical shock hazards that could injure or kill someone if a ground fault occurs
Fire hazards from electrical overloads that go unchecked

Damage to appliances that are plugged into an outlet with unpredictable power flow
Inability to reset the GFCI leaves the outlet without power, impacting essential appliances or devices

A faulty GFCI that still provides power but doesn’t trip poses the greatest safety risks. Appliances can overload the circuit and GFCIs are the last line of defense to cut power when that happens. If they don’t trip as intended, fires or serious shocks could occur.

Replacing a Bad GFCI Outlet

Here are some step-by-step tips for safely replacing a faulty GFCI outlet in your home:

Turn off the power: Switch off the circuit breaker controlling the GFCI outlet at your main electrical panel. Use a contact voltage tester to confirm power is off.
Remove the cover plate: Unscrew and take off the cover plate so you can access the outlet wiring.

Disconnect wires: Carefully disconnect the hot, neutral, ground, and connected circuit wires from the outlet.
Remove old outlet: Unscrew the mounting screws to take the faulty GFCI outlet out of the electrical box.
Install new GFCI: Screw the replacement GFCI outlet securely into the box and re-connect the wires properly to the matching hot, neutral, and ground screw terminals.

Reset breaker: Turn the circuit breaker back on. Check that the outlet now has power and test the GFCI using the test and reset buttons.

A GFCI outlet replacement is a project many DIYers can safely take on. The key things are to always turn off power at the breaker, use caution when working with electrical wiring, and be sure to connect the wires to the correct outlet terminals.

If you don’t feel comfortable doing electrical repairs yourself, contact a licensed electrician to replace the bad GFCI.

GFCI Tripping Breaker

If a GFCI outlet is causing the circuit breaker to trip, this usually indicates a more serious underlying problem:

Damaged or overheated wiring between the GFCI and breaker
Short circuit in the GFCI or somewhere downstream on the circuit

Too high of an electrical load on the circuit
Incorrectly wired connections to the GFCI

Replacing the GFCI may temporarily fix the tripping breaker if the old outlet was defective. But if the new GFCI also trips the breaker, the other potential issues need to be investigated. Contact an electrician to diagnose and safely correct tripping issues between the GFCI and circuit breaker.

GFCI Keeps Tripping with Nothing Plugged In

If your GFCI trips even when nothing is plugged into the outlet, this typically means the GFCI itself is faulty and needs to be replaced. However, there are a couple other possibilities to check first:

Voltage fluctuations: Large fluctuations in your electrical service voltage can cause a GFCI to nuisance trip, especially if it’s older. Check if lights dim or brighten when the GFCI trips.
Shared neutral wire: On older circuits, GFCI outlets may share a neutral wire with other outlets. Faults on appliances downstream can cause phantom tripping even when the GFCI itself has nothing plugged in.

If voltage is stable in your home and neutral wires are separate, the GFCI itself is likely defective. Electrical surges often damage the sensitive trip circuitry inside over time. Replace old or faulty GFCIs to resolve nuisance tripping issues.

How Long do GFCI Outlets Last?

When functioning normally, a GFCI outlet should last between 10-20 years. However factors like moisture exposure, power surges, frequent tripping, and electrical overloads can all shorten their lifespan. It’s a good practice to proactively replace or test GFCIs that are over 10 years old.

High quality commercial and industrial grade GFCIs are available that are designed for 20+ year lifespans in demanding electrical environments. But residential grade GFCIs used in homes do have a limited lifespan.

Typical GFCI Lifespans

Bathroom: 5-10 years
Kitchen: 10-15 years
Outdoor: 5-10 years

Garage: 10-15 years
Basement: 10-20 years

Moisture, temperature swings, and physical exposure to the elements shorten lifespans for bathrooms, outdoors, and garages. Kitchens also involve heat, grease, and lots of plugging/unplugging that wears out components. Regularly test and replace GFCIs on these higher risk circuits every 5-10 years.

Cost to Replace a GFCI Outlet

Replacing a single faulty GFCI outlet with a new device typically costs $10-$30 in materials, plus $40-$100 per hour for an electrician’s labor if hired. Homeowners can often replace bad GFCIs on their own in less than an hour to save on labor costs.

For a professional electrician, the total costs to replace a malfunctioning GFCI outlet will generally run between $50-$200, depending on:

Number of GFCI outlets needing replacement

Accessibility of the outlets
Wiring repairs required
Electrician’s hourly rate

It’s a simple project for a DIYer but always turn off the power at the breaker box before replacing outlets. Consult an electrician if your circuit has complex wiring or other hazardous conditions.

Preventing GFCI Outlet Failure

You can minimize the chances of premature GFCI failure using these electrical safety practices:

Avoid overloading circuits with too many appliances

Use surge protectors to protect against power spikes
Address moisture problems and leaks near outlets
Don’t overtighten screws on the terminal wires

Only reset the outlet after fixing any ground faults
Test and exercise GFCIs monthly to keep components operating
Replace old or damaged GFCI cover plates

Additionally, only use high-quality GFCI outlets from reputable brands that meet UL standards and ratings for durability, heat tolerance, and electrical specifications. Cheap imported GFCIs often fail sooner.

GFCI vs. AFCI vs. Surge Protector

There are 3 common electrical safety devices that people often confuse:

GFCI: Detects ground faults and cuts power to prevent electrocution. Required by code in bathrooms, kitchens, etc.

AFCI: Detects arc faults and cuts power to prevent fires. Now often required on bedroom circuits.
Surge protector: Helps suppress power surges that could damage electronics and appliances.

GFCIs primarily protect people while AFCIs primarily protect property. Surge protectors help protect appliances but don’t replace the need for GFCI or AFCI protection on circuits.

Conclusion

GFCI outlets are essential safety devices that can prevent electrocution and fire hazards when working correctly. But like any electrical component, they can fail over time. Know the warning signs of a faulty GFCI, like frequent tripping or failure to reset, so these protective devices can be promptly replaced.

Test GFCIs monthly and replace outlets that are corroded, damaged, or over 10 years old. Replace malfunctioning GFCIs as soon as possible to avoid the risks of shocks or fire from ground faults going undetected. With proper maintenance, GFCIs can keep your home’s electrical system running safely for years.