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Electrical Safety Topics

Understanding GFCI and AFCI.pdf



Do You Need An Electrician? Who do you call? What questions do you ask?


10 Questions to Ask Yourself About Your Home Electrical System

Do circuit breakers in your home trip often or do fuses keep blowing?

A home electrical system has these built-in safeguards to prevent electrical overload.
Too much current causes the breakers to open automatically or the fuses to melt.
When a circuit shuts down repeatedly, it's a warning that should not be ignored.

Are GFCI outlets installed where required?

The National Electrical Code now requires extra protection for outlets in specific areas of the home, such as kitchens, baths, utility rooms, garages and outdoors. Ground-fault circuit interrupters (GFCIs)— which are identifiable by their TEST and RESET buttons—are generally required in proximity to wet locations. If your wiring has not been upgraded with GFCIs you're not protected.

Are extension cords needed to reach the outlets in any room?

Electrical outlets, especially in older homes, are often spaced too far apart for modern living. This not only creates too much demand on too few outlets, it also poses a hazard when the extension cords are run under rugs and furniture.

Is there rust on the main electrical service panel?

Even permanent fixtures wear out or suffer the ravages of time. When rust appears on the metal service panel it often indicates a moisture problem or that deterioration has reached an advanced stage.

Do the lights dim when appliances turn on?

High-demand appliances such as air conditioners, clothes dryers, refrigerators and furnaces need extra power when they start up. This temporary current draw can be more than just a nuisance; it can damage sensitive equipment.

Do electrical switches or outlets feel warm or tingly?

Loose or deteriorating electrical connections, such as the wiring junctions in switches and outlets, impede current flow and create resistance. THis may create a dangerous condition that can result in shock or fire.

Do your electrical outlets need accessory plug-strips?

Too many things plugged in at one location can create more current demand than a single outlet or electrical line can safely handle. Adding multiple plug-in strips won't solve the problem. What you need are additional outlets, and possibly new wiring runs to service them.

Do your outlets not accept three-prong plugs?

The third, or grounding, prong on a typical appliance plug provides an extra measure of safety against electrical shock. Older two-prong receptacle outlets, installed in homes before this innovation, may not be adequately grounded and should be upgraded.

Is the wiring in your outlet boxes old and crumbling?

If you look at the wiring to your home's light switches or outlets, do you find wires wrapped in cloth sheathing or bits of black rubber in the electrical box? Very old homes often have antiquated wiring that should be upgraded to ensure your safety.

Have you never upgraded your electrical service?

If your home is over 25 years old, you could have an inadequate and possibly hazardous electrical system—and not even know it. To be safe, call in an electrician for a thorough inspection, and if necessary bring your home up to today's electrical code standards.

Questions to Ask an Electrician

If you need to consult a professional electrician or electrical contractor, ask the following questions to learn whether the individuals you're considering are fully qualified and likely to do reliable work at a reasonable price.

Are you licensed in this municipality?

Not all states, counties or towns regulate or require licenses for electricians, but it's prudent to check first with your local building department. Also ask if electrical work in your municipality must adhere to standards established by the National Electrical Code.

Will my electrical panel need replacement?

The current National Electrical Code recommends a minimum 100-amp incoming electrical service. If your service panel provides less, it should be upgraded to this level or better to meet today's home requirements. Most new homes are wired with 200-amp service.

Will I have to apply for a permit?

If a permit is required, the electrician often will make the application for the homeowner. Some municipalities allow homeowners to do minor electrical repairs and installations if they first secure a permit and have the work inspected when complete.

Is my home's electrical system adequately grounded?

Ground-wiring protects a home and its occupants in case of an electrical fault, such as a short-circuit. But grounding also protects expensive electronic equipment like computers and many appliances. An electrician can quickly check and add grounding capacity if needed.

Are there any hidden costs for the work?

The electrician should do a thorough preliminary inspection and provide you with a firm, accurate estimate of the work involved, along with the cost of fixtures or wiring that will be installed. If additional work is necessary, it can be negotiated and billed separately.

Will you use all-copper wiring for any new installation?

Solid copper wiring is the material of choice for new homes or renovations. Although 14-gage wire is allowed for many circuits, it's smart to install heavier 12-gage wiring, which costs a little more but can handle more electrical current, making it safer and more energy-efficient.

If my service needs upgrading, will the entire house have to be rewired?

Unless you live in a very old home with antiquated wiring, you probably won't have to replace your existing electrical lines. However, if you require more electrical capacity in certain rooms, new wiring runs and additional outlets are likely to be needed.

Can you provide references from other homeowners?

Every tradesperson or electrician is only as good as their reputation. If you have never contracted with the electrician who answered your call, it's fair to ask for the names of other homeowners who have and to give them a call to check the contractor's work.

Copper Development Association Inc. assumes no responsibility or liability of any kind in connection with this publication, and makes no representations or warranties related to its use, accuracy or utility.

Why GFCI's Fail
(Taken from Occupational Health and Safety Magazine, November 2000
Reprinted with permission © 2000, Stevens Publishing Corporation)

Joseph E. Layton
Stevens Publishing Corp.

Electricity has been around since the beginning of time in the forms of lightning and static electricity. In 600 BC in Greece, it was observed that amber rubbed with wool would attract light objects such as straw, feathers, and bits of wood. Around 1570, William Gilbert, the man who is credited with coining the word “electricity,” discovered electrical properties in items other than amber. The electric light bulb was invented in 1802, and Thomas Edison was the first person to successfully market an incandescent lamp, in 1879.

With the ever-expanding use of electricity, the need was recognized for a national standard to regulate electrical installations nationwide. The National Electrical Code came into being in 1897. Through the National Fire Protection Association it became NFPA 70 and remains the same today. It is the electrical standard for the United States and other foreign countries, including Mexico. The code is not a training manual; rather, it is a uniform standard used by inspection agencies, designers, insurance companies, and others who are responsible for electrical installations. The code is a minimum requirement for safe installations, and parts of the code became Subpart S and Subpart K of OSHA’s standards.

When electricity became part of our lives, whether in the workplace or at home, effective grounding became our means of protection. Grounding is still a required method of protection from shock in the event of an electrical fault. This is the separate wire that is run with the circuit conductors and connected to the non-current-carrying metal parts of equipment that could become energized because of a fault.

A grounding conductor is also required in cords that are connected to tools, equipment, and appliances. The only exception is if the tool is supplied through an isolation transformer with an ungrounded secondary of not over 50 volts or uses a system of approved double insulation. The grounding conductor gives a direct path back to the grounding electrode (ground rod, structural steel, etc.) if a fault occurs.

When the transistor was invented, we entered into a new era. Now, we were faced with items such as transistor radios, which operated on batteries or regular household current. In the mid to late 1960s, one could hardly read a newspaper or watch the evening news without reading or hearing about a kid or kids being electrocuted. Typically they would be sitting in the bathtub when their radio (plugged into household current) fell into the tub, and electrocuting them.

Hairstyles were changing during this period, and the hand-held hair dryer became a part of practically every household. They posed a problem because they were primarily used in the bathroom, near the lavatory. This presented additional hazards because the water piping system was grounded, and a fault in the hair dryer along with someone coming in
contact with the faucets could result in serious electrical shock or electrocution.

These factors led to introduction of Ground Fault Circuit Interrupters (GFCIs).

One of the items covered in the National Electrical Code is Ground Fault Circuit Interrupters, or GFCIs. The GFCI is probably the most significant life-saving device ever invented for protection against serious injury or death caused by an electrical shock.

The GFCI is designed for “personal” protection, not for protection of equipment or the conductors of a circuit. While grounding is required and is a vital part of the safety of both people and equipment, the grounding conductor has nothing to do with the operation of GFCIs.

The GFCI senses an imbalance of current between the “hot” and “neutral conductor.” The GFCI really does not care about the current draw (amps) passing through, as long as it is within the designed limits of the device. Rather, it is monitoring the current difference in milliamperes between the hot and neutral. A milliamp is .001 or 1/1000 th of an ampere. If this difference is at 5 milliamperes, plus or minus 1 milliampere, the device “trips out,” breaking the circuit.

A handheld hair dryer that is rated at 1,400 watts, 120 volts, will have a current draw of approximately 11.6 amperes, or 11,600 milliamperes. An industrial 3/8-inch electric drill will have a current draw of between 4 and 6 amperes, or 4,000 to 6,000 milliamps.

While electricity performs many tasks for us and makes our lives more enjoyable, it is basically lazy. The lazy part is that it will seek the path of least resistance to a grounding source. The resistance in a copper wire used as the grounding conductor is very low and will allow current to flow rather freely. In the event of an electrical fault in equipment that has a grounding conductor, the current will flow to ground on the conductor.

The adult body has about 500 Ohms of resistance. If a person’s body were to become the path to ground, the body would become a high impedance ground path. There is not enough current flowing through the body to trip an overcurrent device (a fuse or circuit breaker; the GFCI is not an overcurrent device.)

In order for an overcurrent device to trip, the current draw (amps) must exceed the rating of the device. For example, a circuit breaker rated at 20 amperes will not trip open until the current exceeds the 20 amperes. Using Ohm’s Law, on a 120 volt circuit with 500 Ohms of resistance, the current level would be 240 milliamperes, or about 1/4 th of an ampere. Even though this seems like a small about of current, it is quite deadly when passing through the body.

Shock in the range of 6 to 30 milliamps can be very painful, and the person in contact cannot let go of the circuit. At around 50 milliamps respiratory arrest is possible, with severe muscular contractions. Ventricular fibrillation starts around 67 milliamperes of current. This is when the heart basically starts fluttering and is not pumping blood through the system. If not stabilized, death is a real possibility.

So you can see that if the GFCI is functioning properly, the current level will never reach the danger point—because it trips at 5 milliamperes.

UL 1943 is the standard for testing GFCIs. Each manufacturer must ensure that its product meets this standard. Included in the listing and labeling for GFCIs are instructions that they be tested monthly.

Both the National Electrical Code and OSHA’s electrical standards require that equipment shall be used and installed in accordance with any instruction included in the listing and labeling. The purpose of this is to ensure as much as possible that the device is functioning properly.

The test is a very simple procedure where one can press the test button on the device to ensure that it does trip, breaking the circuit. This test button creates a difference of 5 milliamperes between the hot and neutral through a resister built in the device. There are GFCI testers in the marketplace where you can test the polarity of a receptacle and also trip the GFCI. I have stated that the grounding conductor has no part to play in the operation of the GFCI, but using the external tester the grounding conductor must be present because the tester is using the hot and grounding conductor to trip the device.

We take for granted that our GFCIs are providing protection if we can operate a tool, hair dryer, or other item through them. Yet this is not always the case. While the device will allow current to flow through it, the monitoring of the current may not be taking place.

Built into the device is a metal oxide varistor (MOV) used as a surge suppressor. The MOV absorbs the voltage surge and converts it into heat. Repeated surges can degrade the MOV, still allowing current to flow but not providing the protection required. Voltage surges such as lightning strikes in the area can cause a surge, as can utility company switching. In the event a GFCI trips out, is reset, and power is restored, you should go a step further and press the test button to insure that the device trips open to stop the current flow. If the device will not trip open, or if it trips and current continues to flow, the device is defective and must be replaced.

Some parts of the country are more susceptible to lightning strikes than others. This is a primary cause of GFCI failures. The International Association of Electrical Inspectors obtained information from the American Society of Home Inspectors about its findings in inspecting residences. This survey only covered parts of the United States, and some of the figures are staggering about the number of GFCIs that do not operate properly.

In parts of Florida, up to 58 percent of the GFCI circuit breakers were defective, and 33 percent of the receptacles. Of the states from which information was obtained, Washington state had the least number of failures. The survey covered parts of New York, Florida, Texas, California, Washington, and Illinois. IAEI, ASHI, and the National Electrical Manufacturing Association are joining forces get data from each state to give a true picture of the failures throughout the United States.

If you follow just these two steps, whether at home or at work, you can help ensure that your GFCIs function as life-protecting devices.

  1. Test them monthly as required.
  2. When a GFCI trips, reset and then trip it using either a GFCI tester or test buttons on the device. (Make sure this stops the current flow). Reset and use the circuit!

Joseph E. Layton ( is president of Layton’s Electrical Consulting Inc., located in King, N.C. He is a member of the American Society of Safety Engineers, the International Association of Electrical Inspectors, and the National Fire Protection Association.

GFCI 2005 NEC (National Electric code)

210.8 Ground-Fault Circuit-Interrupter Protection for Personnel.

FPN: See 215.9 for ground-fault circuit-interrupter protection for personnel on feeders.
(A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.
(1) Bathrooms
(2) Garages, and also accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use
Exception No. 1 to (2): Receptacles that are not readily accessible.
Exception No. 2 to (2): A single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).
Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G)
(3) Outdoors
Exception to (3): Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or deicing equipment shall be permitted to be installed in accordance with 426.28.
Receptacles installed under the exceptions to 210.8(A)(5) shall not be considered as meeting the requirements of 210.52(G).
(4) Crawl spaces — at or below grade level
(5) Unfinished basements — for purposes of this section, unfinished basements are defined as portions or areas of the basement not intended as habitable rooms and limited to storage areas, work areas, and the like
Exception No. 1 to (5): Receptacles that are not readily accessible.
Exception No. 2 to (5): A single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).
Exception No. 3 to (5): A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have ground-fault circuit-interrupter protection.
(6) Kitchens — where the receptacles are installed to serve the countertop surfaces
(7) Laundry, utility, and wet bar sinks — where the receptacles are installed within 1.8 m (6 ft) of the outside edge of the sink
(8) Boathouses
(B) Other Than Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (5) shall have ground-fault circuit-interrupter protection for personnel:
(1) Bathrooms
(2) Commercial and institutional kitchens — for the purposes of this section, a kitchen is an area with a sink and permanent facilities for food preparation and cooking
(3) Rooftops
(4) Outdoors in public spaces—for the purpose of this section a public space is defined as any space that is for use by, or is accessible to, the public

Exception to (3) and (4): Receptacles that are not readily accessible and are supplied from a dedicated branch circuit for electric snow-melting or deicing equipment shall be permitted to be installed in accordance with the applicable provisions of Article 426.
(5) Outdoors, where installed to comply with 210.63
(C) Boat Hoists. Ground-fault circuit-interrupter protection for personnel shall be provided for outlets that supply boat hoists installed in dwelling unit locations and supplied by 125-volt, 15- and 20-ampere branch circuits.

Aluminum wiring article:

Electrical Safety

Electricity is an essential part of our lives. However, it has the potential to cause great harm. Electrical systems will function almost indefinitely if properly installed and not overloaded or physically abused. Electrical fires in our homes claim the lives of 485 Americans each year and injure 2,305 more. Some of these fires are caused by electrical system failures and appliance defects, but many more are caused by the misuse and poor maintenance of electrical appliances, incorrectly installed wiring, and overloaded circuits and extension cords.
  • Never use anything but the proper fuse to protect a circuit.
  • Find and correct overloaded circuits. 
  • Never place extension cords under rugs. 
  • Outlets near water should be GFI-type outlets. 
  • Don't allow trees near power lines to be climbed. 
  • Keep ladders, kites, equipment and anything else away from overhead power lines. 

Electrical Panels
Electricity enters the home through a control panel and a main switch where one can shut off all the power in an emergency. These panels are usually in the basement. Control panels use either fuses or circuit breakers. Install the correct fuses for the panel. Never use a greater numbered fuse or a metallic item such as a penny. If fuses are used and there is a stoppage in power, look for the broken metal strip in the top of a blown fuse. Replace the fuse with a new one marked with the correct amperage. Reset circuit breakers from off to on. Be sure to check why the fuse or circuit blew. Possible causes are frayed wires, overloaded outlets or defective appliances. Never overload a circuit with high wattage appliances. Check the wattage on appliance labels. If there is frayed insulation or a broken wire, a dangerous short circuit may result and cause a fire. If power stoppages continue or if a frayed or broken wire is found, contact an electrician.
Outlets and Extension Cords
Make sure all electrical outlets are three-hole, grounded outlets. If there is water in the area, there should be a GFI or Ground Fault Interrupter outlet. All outdoor outlets should be GFIs. There should be ample electrical capacity to run equipment without tripping circuit breakers or blowing fuses. Minimize extension cord use. Never place them under rugs. Use extension cords sparingly and check them periodically. Use the proper electrical cord for the job, and put safety plugs in unused outlets.

Electrical Appliances
Appliances need to be treated with respect and care. They need room to breathe. Avoid enclosing them in a cabinet without proper openings and do not store papers around them. Level appliances so they do not tip. Washers and dryers should be checked often. Their movement can put undue stress on electrical connections. If any appliance or device gives off a tingling shock, turn it off, unplug it and have a qualified person correct the problem. Shocks can be fatal. Never insert metal objects into appliances without unplugging them. Check appliances periodically to spot worn or cracked insulation, loose terminals, corroded wires, defective parts and any other components that might not work correctly. Replace these appliances or have them repaired by a person qualified to do so.
Electrical Heating Equipment
Portable electrical heating equipment may be used in the home as a supplement to the home heating system. Caution must be taken when using these heating supplements. Keep them away from combustibles and make sure they cannot be tipped over. Keep electrical heating equipment in good working condition. Do not use them in bathrooms because of the risk of contact with water and electrocution. Many people use electric blankets in their homes. They will work well if they are kept in good condition. Look for cracks or breaks in the wiring, plugs and connectors. Look for charred spots on both sides. Many things can cause electric blankets to overheat. They include other bedding placed on top of them, pets sleeping on top of them, and putting things on top of the blanket when it is in use. Folding the blankets can also bend the coils and cause overheating.

Electricity is important to the workings of the home, but can be dangerous, especially to children. Electrical safety needs to be taught to children early on. Safety plugs should be inserted in unused outlets when toddlers are in the home. Make sure all outlets in the home have face plates. Teach children not to put things into electrical outlets and not to chew on electrical cords. Keep electrical wiring boxes locked. Do not allow children to come in contact with power lines outside. Never allow them to climb trees near power lines, utility poles or high tension towers.
Electricity and Water
A body can act like a lightning rod and carry the current to the ground. People are good conductors of electricity, particularly when standing in water or on a damp floor. A body can act like a lightning rod and carry the current to the ground. Never use any electric appliance in the tub or shower. Never touch an electric cord or appliance with wet hands. Do not use electrical appliances in damp areas or while standing on damp floors. In areas where water is present, use outlets with "ground fault interrupters" or GFIs. Shocks can be fatal.
Animal Hazards
Mice and other rodents can chew on electrical wires and damage them. If rodents are suspected or known to be in the home, be aware of the damage they may cause and take measures to get rid of them.
Outside Hazards

There are several electrical hazards outside the home. Be aware of overhead and underground power lines. People have been electrocuted when an object they are moving has come in contact with the overhead power lines. Keep ladders, antennas, kites and poles away from power lines leading to the house and other buildings. Do not plant trees, shrubs, or bushes under power lines or near underground power lines. Never build a swimming pool or other structure under the power line leading to your house. Before digging, learn the location of underground power lines.
Do not climb power poles or transmission towers. Never let anyone shoot or throw stones at insulators. If you have an animal trapped in a tree or on the roof near electric lines, phone your utility company. Do not take a chance of electrocuting yourself. Be aware of weather conditions when installing and working with electrical appliances. Never use electrical power tools or appliances with rain overhead or water underfoot. Use only outdoor lights, fixtures and extension cords. Plug into outlets with a ground fault interrupter. Downed power lines are extremely dangerous. If you see a downed power line, call the electric company, and warn others away. If a power line hits your car while you are in it, stay inside unless the car catches fire. If the car catches fire, jump clear without touching metal and the ground at the same time.
  • Routinely check your electrical appliances and wiring.
  • Frayed wires can cause fires. Replace all worn, old or damaged appliance cords immediately.
  • Use electrical extension cords wisely and don't overload them.
  • Keep electrical appliances away from wet floors and counters; pay special care to electrical appliances in the bathroom and kitchen.
  • Don't allow children to play with or around electrical appliances like space heaters, irons and hair dryers.
  • Keep clothes, curtains and other potentially combustible items at least three feet from all heaters.
  • If an appliance has a three-prong plug, use it only in a three-slot outlet. Never force it to fit into a two-slot outlet or extension cord.
  • Never overload extension cords or wall sockets. Immediately shut off, then professionally replace, light switches that are hot to the touch and lights that flicker. Use safety closures to "child-proof" electrical outlets.
  • Check your electrical tools regularly for signs of wear. If the cords are frayed or cracked, replace them. Replace any tool if it causes even small electrical shocks, overheats, shorts out or gives off smoke or sparks.