GFCI outlet being tested (C) Daniel Friedman Electrical Inspection & Test Procedures for GFCIs and AFCIs
Requirements for GFCI Testing

  • POST a QUESTION or READ FAQs about how to inspect the operating safety & condition of arc fault circuit interrupters and ground fault circuit interrupters

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

How to inspect AFCIs and GFCIs:

How should we test a ground fault circuit interrupter or arc fault circuit interruptor that is already installed in a building? Do the push-button tests form a complete test? What wiring errors will be disclosed or missed by the usual test procedures for these devices?

Here we provide a Guide to Inspecting and Testing Electrical Receptacles or "outlets" and GFCI-Protected Receptacles. Safety considerations during the inspection or test of GFCIs - ground fault circuit interrupters.

Safety considerations during the inspection or test of AFCIs - arc fault circuit interrupters. Electrical Inspection procedures for the inspection of GFCIs and AFCIs for home inspectors & electrical inspectors.

This article series discusses safety procedures for the electrical inspector, home inspector, or other professionals while examining GFCIs and AFCIs. Safe electrical inspection procedures and safe use of volt meters, DMMs, multimeters, and similar electrical test equipment is discussed at the end of the article.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Inspecting and Testing Electrical Receptacles or "outlets" and GFCI-Protected Receptacles

GFCI circuit breakers in an electrical panel (C) Daniel Friedman at

Article Index


AFCI & GFCI Testing & Inspection Standards

These electrical inspection suggestions are not a complete inventory of all electrical safety procedures nor of all electrical components that should be inspected; these notes focus on identification of conditions that may present special electrical hazards for the electrical inspector.

8.1.F. [The inspector shall observe] the polarity and grounding of all receptacles within six feet of interior plumbing fixtures, and all receptacles in the garage or carport, and on the exterior of inspected structures

Receptacle and GFCI Test Procedure (C) Daniel FriedmanTesting is commonly performed using one of a variety of electrical testers. First perform the visual inspection for overheating, looseness, arcing as noted above for switches. If a device is quite loose we do not test further but report it as a required repair. [See "Electrical Receptacles" in this issue.]

8.1.G. [The inspector shall observe] the operation of Ground Fault Circuit Interrupters.

While manual operation of these devices using their internal test button is possible, experience and information about the construction and operation of these devices and the circuits which they serve suggest that testing using GFI-test equipment adds additional information and will find defects not disclosed by manual operation. See "GFCI's" in the original issue of the ASHI Technical Journal.

Electrical "outlet" receptacle testers like the ones shown in these two photos are used by most home inspectors to check for proper wiring at electrical receptacles as well as to check the function of GFCI's.

An electrical receptacle which has been wired 'downstream' from a GFCI or AFCI will be protected by that device provided that the wiring has been connected properly.

We find often that these devices were not wired correctly. For example, reversing the "line" and "load" wiring when installing a GFCI will prevent it from functioning properly even though the installer may test it and think it's fine.

We provide details about using receptacle testers at ELECTRICAL TOOLS BASIC

Requirements for Regular GFCI Testing in the Workplace and in Private Residences

Question: how often should a GFCI be tested in the workplace? Should tests be documented?

2018/07/27 craig said:

How often are CGFIs to be inspected on a commercial site? Is documentation mandatory?

Reply: workplace GFCI Testing Requirements: test monthly, keep a test log

OSHA 1926.404, Wiring design and protection addresses electrical wiring and equipment, and 1926.404(b)(i) requires the use of GFCI.


General. The employer shall use either ground fault circuit interrupters as specified in paragraph (b)(1)(ii) of this section or an assured equipment grounding conductor program as specified in paragraph (b)(1)(iii) of this section to protect employees on construction sites. These requirements are in addition to any other requirements for equipment grounding conductors. - Source: OSHA Standards 29 CFR K Electrical, 1926.404 Wiring Design and Protection [PDF] retrieved 2018/07/267, original source:

In interpreting 1926.404 in the workplace OSHA has commented on GFCI test protocols for the workplace as follows:

Section 1926.404(b)(1) does not require GFCIs to be tested.

However, 1926.20(b)(2) does require the frequent and regular inspections of equipment. The instructions included with the devices indicate that they should be tested monthly.

If an employer can demonstrate, for example, by means of logs or procedures, that he or she tests GFCIs monthly and promptly replaces those found defective, then a serious citation may not be appropriate for defective GFCIs found upon inspection, provided the faulty devices are replaced promptly.

OSHA was referring to U.S. Regulations Standards-29-CR, Part 1926, Safety and Health Requirements for Construction, that includes this provision:

1926.20(b)(2) Such programs shall provide for frequent and regular inspections of the job sites, materials, and equipment to be made by competent persons designated by the employers. - Source: OSHA Standards 29 CFR 1926 C General Safety and Health Provisions [PDF] retrieved 2018/07/27, original source:

Read details at GFCI WORKPLACE TEST REQUIREMENTS OSHA - retrieved 2018/07.27, original source:

Note: some GFCI devices such as Pass & Semour's Legrand GFCI conducts automatic self-testing and will self-disable if a fault is detected. Details are in the Legrand instructions found at our collection of all GFCI manufacturer's installation manuals at GFCI INSTRUCTION & TESTING INSTRUCTIONS

Watch out: as we explain at GFCI TESTING on UN-GROUNDED CIRCUITS (e.g. Knob & Tube) using the integral TEST button on a GFCI is not a complete nor completely-reliable test and will not address all GFCI installations & conditions.

Residential GFCI Testing Requirements: test monthly

In residential properties there is no direct statutory requirement for GFCI testing, though the manufacturer's instructions should be followed, such as "test monthly".

However a careful reading of the U.S. NEC Article 110 requires instructions from the product manufacturer to be followed. That should be interpreted as a code requirement for monthly testing of GFCIs in residential properties as well.

Really? Yes. However in my [DF] experience, few if any homeowners regularly test GFCI devices in their homes. I and other inspectors have found GFCI devices that have never worked properly since original installation, having been improperly wired at that time.

U.S. National Electrical Code NEC Article 110.3 (B) requires GFCI testing - excerpt:

110.3 Examination, Identification, Installation, and Use of Equipment
(B) Installation and Use.

Equipment must be installed and used in accordance with any instructions included in the listing or labeling requirements.

Note: In the U.S. NEC, article 110 applies generally to electrical conductors and electrical equipment all electrical installations.

Example of a Manufacturer's Instruction for testing GFCIs

Press the TEST button (then RESET button) every month to assure proper operation.

If the Status Indicator Light does not turn Green when the RESET button is depressed and then released, or the GFCI cannot be reset, it must be replaced.

- Source: Leviton, GFCI INSTALLATION & TEST PROCEDURES [PDF], retrieved 2018/07/27, original source:

Safe Use of Electrical Test Equipment: DMMs & VOMs

The following example of electrical inspection limitations & safety for home inspectors is excerpted from an ASHI standard:

8.3 During an electrical system inspection the inspector is NOT required to

8.3.A. insert any tool, probe, or testing device inside the panels


How to Test digital volt meter DMM or Volt Ohm Meter VOM meter condition

Safe Use of Electrical Test Equipment: DMMs & VOMs

8.3 During an electrical system inspection the inspector is NOT required to

8.3.A. insert any tool, probe, or testing device inside the panels


In some circumstances ASHI inspectors may elect to make current and voltage measurements. For inspectors who elect to use these tools, make sure that the tools themselves do not become a source of damage, or injury.

Use only DMM's (digital multi meters) or VOMs (volt-ohm meters, the analog predecessors to DMMs) designed for high energy measurements.

Details about safe use of VOMs and DMMs are provided at DMMs VOMs SAFE USE OF.

These electrical inspection suggestions are not a complete inventory of all electrical components that should be inspected; these notes focus on identification of conditions that may present special electrical hazards for the electrical inspector.

Using a DMM or VOM to Check for Current

VOM in use measuring live voltage (C) Daniel Friedman

A simple volt ohm meter volt-ohmeter (VOM) such as the TriplettTM 310 or our little mini digital multimeter (DMM) shown at left can be used to test for unexpected and unsafe voltage at a component.

  1. Set the VOM in the highest AC-voltage range.
  2. One probe is used to contact the surface of the electric panel (or any component to be examined)
  3. The other probe is touched to a reliable ground source, or in the example shown, to the neutral side of the circuit.

NOTE: Once having tested at the highest voltage range, greater accuracy may be obtained by choosing more sensitive ranges which permit readings to be taken in the upper portion of the scale. Disconnect the test probes (or shut off the voltage source) before changing the voltage range setting on the VOM.

Details on safe use of DMM's and VOMs are at DMMs VOMs SAFE USE OF.

For example, if the meter indicates more than 1or 2 volts between a service panel cover and ground, there's a safety problem. Most low-cost analog-type meters such as the one described provide additional ranges used to read lower voltages with more sensitivity.

Some VOM models provide alligator clips for the ends of the test probes. These clips permit measuring high voltage without handling the probes. Always shut off the power before connecting the alligator clips.

Inspecting Arc Fault Circuit Interrupters AFCIs - Safe Procedures

Arc fault interrupter circuit breaker - US CPSC

AFCIs: The requirement to inspect and test AFCIs is already in some regulations for home inspectors. It seems likely that remaining home inspection associations and state or provincial inspection standards-writers will soon update their electrical inspection standards section to address the new requirement for AFCI's.

See AFCIs ARC FAULT CIRCUIT INTERRUPTERS for details of the electrical code changes regarding the requirement for arc fault interrupters in homes, the effectiveness of AFCIs, and nuisance tripping problems with AFCIs.

AFCIs can be properly tested only by using the test button on the device itself. External tool tests are incomplete and therefore unreliable.

There have been some recalled AFCI devices that might not work reliably. If you had the bad luck to try your amateur test on one of these, the results could be a disaster.

See this Federal Pioneer AFCI recall issued by Schneider Electric.

ELECTRICAL INSPECTOR SAFETY PROCEDURES describes important basic safety procedures, clothing, and equipment for home inspectors and electrical inspectors.

Testing GFCIs on Un-Grounded Knob and Tube Electrical Circuits

Knob and tube wiring example (C) Daniel Friedman

A ground fault circuit interrupter can provide shock protection for an electrical circuit that has no ground present, such as a knob and tube electrical circuit.

The GFCI device will still work if it detects a current leak to ground - say if an occupant drops their hair dryer into the sink (which is full of water grounded via the building plumbing system).

But can you test the GFCI protection feature of a GFCI receptacle installed on a knob and tube circuit

There are two "answers":

  1. No:  the GFCI test device or internal GFCI test exercised by the test button depends on being able to produce a small internal current leak to ground. Since there is no electrical ground wire present, the test feature won't work.
  2. Yes, sort-of: you could rig your own test of a GFCI device on a knob and tube or other un-grounded circuit by making a connection from the hot lead of the receptacle to a known ground such as a water pipe or radiator. We've demonstrated this procedure using a test instrument as well as a bare wire.

    Watch out: DO NOT DO THIS unless you are specially trained and equipped to do so. It is dangerous for various reasons including the chance that you or a bystander will be killed by electric shock.

There have been some recalled GFCI devices that would not work reliably. If you had the bad luck to try your amateur test on one of these, the results could be a disaster.


See details of 2-wire, un-grounded electrical circuits such as un-grounded receptacles or "outlets" at ELECTRICAL CONNECTION for 2-WIRE RECEPTACLE CIRCUIT

2008 Code Changes Affecting Ground Fault Circuit Interrupters GFCI's

Please see details now moved to GFCI PROTECTION, GFCI CODES

General Safety Suggestions for Electrical Inspectors

Pay attention, look carefully, move slowly before opening or exploring electrical equipment. Learn to recognize indications of a problem, such as but not limited to the examples in this article.

Do not assume anything when performing dangerous tasks such as inspecting electrical equipment.

Do not touch live wires or connections. Watch your hands and other body parts. Handling live electrical wires without special training and equipment is highly questionable and often fatal.

December 12, 1988 - Madison, WI - Michael E. Hammes, 26, died in an apparent electrocution while working in Madison. Hammes had been hired by CUNA Mutual Insurance Society to change ballasts on fluorescent lights. Authorities said he was replacing a fixture in a fourth floor bathroom while standing on a stepladder when he slumped to the floor.

Hammes apparently was electrocuted when he touched live wire with one hand and a metal partition with his body or other hand, according to Dana County Coroner Ray Wosepka.

Hammes was a first-year electronics student. Wosepka said his investigation showed the light fixture had been properly wired. Hammes apparently replaced a ballast, a [transformer] that controls the electrical flow to the light bulbs, and was attaching the live wire when it electrocuted him, Wosepka said. -- Ibid.

If in your opinion unsafe conditions exist at a property you are inspecting you should notify all parties concerned, including building occupants/management/owners, realtors involved, and other appropriate authorities.

December 18, 1988 - Smyrna, GA - A Smyrna family's troubles with a faulty circuit breaker in their mobile home ended in tragedy when a fire broke out and killed 18-year-old Jeffrey Scott Auton. Auton's family, experiencing problems with the main circuit breaker, went to a home products store to buy a new one for their trailer, said Fire Investigator David Herndon.

The store did not have a circuit breaker to fit the family's needs and a new one had to be ordered. .... Herndon said the fire was started when the circuit breaker shut down completely as three space heaters were running.

The family had a history of problems with the breaker, particularly from a load put on it by a large heating unit. Herndon stated that after the fire there was not a trace left of the circuit breaker; it was completely gone from the panel. -- Ibid.

For example, what if the case above had happened the day after the property described had been examined by an ASHI inspector?

Were there perhaps clues which telegraph a developing problem? What about anecdotal reports from the occupants of recurrent breaker tripping, visible signs of overheating in the panel, widespread and unusual use of electric heaters, or evidence of work in the panel by untrained people?

These risks to occupants are also a hazard to the inspector on several bases.

Protect yourself and your client from injury using but not limited to the suggestions we provide here and just below.

Electrical Inspection Safety Suggestions from Rex Cauldwell, a Master Electrician

OPINION-RC: "As a master electrician, here is how I teach opening a service panel in my seminars: "The lucky 7""

  1. Eye protection: Wear safety glasses--electrical panels have been know to explode upon opening.
  2. Insulating gloves: Wear rubber dishwashing gloves--panels have been known to become electrically hot as a screw falls when cover is removed.
  3. Look before touching: Don't approach the panel until you give an overall look of the surrounding area to see if anything looks wrong--such as water on the floor under the panel.
  4. Avoid Shock Pathways: Don't have any part of your body touching items adjacent to the panel.
  5. Insulating floor pad: On a concrete or dirt floor, lay down a thick rubber Welcome mat and stand on it as you open the panel (wear rubber-soled shoes).
  6. Insulating tools: Use insulated handle tools--I use a Milwaukee electric screwdriver.
  7. Panel Door & Screws: Once door is open (in a Federal Pacific panel (and some other models) beware of falling trim and breakers that pop out), set door aside and don't lose the screws

-- Rex Cauldwell

Further Safety Warning--DF: these are helpful electrical safety suggestions from an experienced electrician. No list of suggestions is incomplete and these presume that they are being followed by an experienced, licensed electrician.

For example, there are almost certainly gloves and/or boots specifically recommended for this application; there are specific safety details to look at and for before touching an electrical panel, and procedures for using electrical test equipment to test or examine a suspect electrical panel.

Recommended books on electrical wiring:

Rex Cauldwell's Wiring A House - available online.

Rex Cauldwell's Safe Home Wiring Projects - available online

Electrical Inspection Follow up and Client Safety

A home inspector or electrical inspector who has reported a very unsafe condition, recommended immediate action, and yet may later learn that occupants of the building were nearly killed by work by an incompetent repairman. [NOTE: Port Jervis, NY, AHS Ctl#4658911, 7/10/90.]

What can be done to reduce the chance of this terrible consequence?

Recommending action on an unsafe condition can convert a pre-existing problem into an immediate catastrophe if the client or owner calls an untrained person to the property or if he attempts a do-it-yourself repair.

Often a referral to local fire inspector, electrical inspector, or utility company can help assure that repairs are prompt, proper, and safe. If you recommend immediate action for an unsafe condition, where possible you should provide some means for the client or building owner to assure that the action which is taken is proper and safe.

Inspectors are properly nervous and reluctant to prescribe the actual repair that is needed at a property - they may not know the detailed repair procedure, or there may be alternative repairs, or their description may prompt an un-trained person to try to do the work.

The Building Owner or Building Manager Needs to Know About Unsafe Conditions that Need Immediate Action

The inspector should inform the appropriate parties both orally and in writing any suspected unsafe conditions.

If an area or component could not be fully inspected, the inspector should explain in writing why she or he did not enter or examine an area or component, and what additional inspections or steps should be taken, as well as the general risks that may be present.

Handling Immediate Threats to Life and Safety at a Building Inspection

If in the inspector's judgment equipment is an immediate threat to life and property, such as a boiler whose flue connection has fallen off, we recommend that dangerous equipment be shut down and the appropriate people notified.

See SHUT DOWN UNSAFE EQUIPMENT. In some cases "appropriate people" includes not only the client and building owner, but also building occupants.

In some instances such as sparking electrical panels, gas leaks, or evidence of a fire, the inspector and everyone else should leave the building immediately and from outside, call the fire department and as appropriate, the gas company, police, or rescue person

Reader Comment: reports defective GFCI Test Button in New Device

(Aug 6, 2014) Dick N said:

In regarding your statement at BACK-WIRED ELECTRICAL DEVICES

"For example, if you connect the incoming "hot" wire and neutral wire to the "load" terminals on a GFCI, and if you connect wires leading to downstream electrical receptacles to the "line" terminals (these are the incorrect connections), then pushing the test button on the GFCI will not activate that device's internal trip mechanism."

I recently picked up a used Leviton "spec grade" (stamped thus on the mounting strap) GFCI outlet which was stuck in the "tripped" condition and could not be reset. I partly disassembled the device and discovered that the TEST button doesn't test anything except the TEST button and, arguably, verifies that the contacts aren't welded together. It could have at least been designed to move the solenoid plunger, thus verifying that the mechanical linkage works, but alas it doesn't even do that. Ironically, the instruction "TEST MONTHLY" appears on the front.

Henceforth, before buying any GFCI outlet, I will push the TEST button in the store before I pay for it. If it trips with no line power, it obviously doesn't test the circuitry.

After repair, which involved bending a couple of springs, it works as it appears designed to work - trips upon ground fault or TEST button, and the RESET button resets it.

This device breaks neutral also. Is that really necessary?

This comment was posted originally at BACK-WIRED ELECTRICAL DEVICES



We discuss the "test button" on GFCI devices [in the article above]

In my opinion a GFCI should break both hot and neutral wires. a dangerous short could occur on either of those wires, and in ways you may not anticipate. Consider a shared-neutral: cutting off power at a device by opening the "hot" wire won't protect someone touching a neutral wire that is still carrying current because something is plugged-in and running at a different receptacle that shares the same neutral wire.

See MULTI-WIRE CIRCUITS for details.

Adding complexity to debugging GFCI wiring, my ex-brother-in-law Matt W., who had electrical wiring experience only as a theater electrician, over-tightened the strain relief connectors on the BX wiring thought a NY City apartment.

On turning on power all the hot-to-ground shorts were found right away. But it took more sleuthing to come up with continued GFCI tripping that we traced to strain reliefs that had cut into the neutral wires. There were shorts hot to ground, hot to neutral, and neutral to ground.

You are not quite right that the test button does not test anything.

The test button, using an internal circuit in the GFCI device, tests the trip mechanism itself - within the device. But because it's using an internal circuit, that test is incomplete and will not detect some wiring errors nor a missing ground connection.

Pressing a test button on the device when it is not powered is ambiguous.

Keep in mind that the GFCI, working properly, should detect BOTH a short of hot to ground AND a short of hot to neutral. That's why you see it breaking the neutral when tested.

Watch out: I would never rely on a GFCI or AFCI that someone had opened, modified, bent springs, etc. The result may be unreliable, unsafe, risking fire or shock.


Continue reading at AFCIs ARC FAULT CIRCUIT INTERRUPTERS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see AFCIs vs. GFCIs - what's the difference between an arc fault circuit interruptor and a ground fault circuit interruptor?


Or see this

GFCI Article Series


See FREEZE-PROOF A BUILDING where we describe GFCI protection on heat tape circuits powering heat tapes for manufactured and mobile homes. Similar issues regarding building water entry control are discussed at Sump Pump Inspection.


Suggested citation for this web page

AFCI GFCI TESTING & SAFETY at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

HTML Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman