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Answers To F.A.Q.

 These are some of the questions I was asked by people not in the trade, but people wanting to know how to get electrical help and know more about the work done by electricians.
 Don't expect a lot of technical explantions on how electricity and the electrical trade work. The intention of this website is to help everyone understand electrical terms, not cause more confusion.
 Please feel free to use this FAQ. page from the  Free Electrical Answers Web Site  as a bookmark, on a website, or anywhere it might be of some help.
 If you do use this page on your web site a link back to the  Free Electrical Answers Web Site would be appreciated. Bob.

How hard is it to become an electrician?
When is it time to call an electrician?
How do I find a good electrician?
What is a bonded electrician?
What size service do I install in my home?
Where do you put G.F.I.'s?
Can you use a G.F.I. in an ungrounded outlet?
How much should I attempt on my own?
Do I need to spend all this money?
How many outlets should I have in each room?
How should outlets be installed in a kitchen area?
Where do you install smoke detectors?
How safe is Aluminum wire?
How can I save money on my electric bill?
Should the ground lug on a receptacle be up or down?
How is electricity produced in a circuit?
What is the neutral wire?
Why isolate the neutral in a sub panel?
What is a ground rod?
What size generator should I get?
Why do you need a transfer switch on a generator?
What is power factor?
What is the National Electric Code?
How can you stop static electricity?
What causes lights to dim?
What are Harmonics?
What is an AFCI?

How hard is it to become an electrician?...
 I can promise you one thing you will never be bored with this trade. But getting your license is not easy. I know in my state you need to serve 8,000 hrs as an apprentice and have three years of school. The best way to get started is to try to get into a union apprenticeship program. You also might want to check with local electrical contractors in your area. Some industry and electronic plants have training programs. Keep checking the want adds, sometimes just getting in on maintenance is a start. Once you get that piece of paper there is no limit to what you can achieve both financially and rewardingly. It all depends on how much ambition you have. If you want to get a jump the best books i found were at the library. There is a book called the American Elecricians Handbook that is put out by Terrell Croft,With Wilford Summers / Hardcover / McGraw-Hill Companies. Just about everything you need know is in this book. Also the National Electrical Code Book is a book you will have to learn to get your license. Both these books can be purchased online or at most electrical supply stores.
 The union apprenticeship program is probably the best in the world, and I would recommend it highly to anyone seeking to become an electrician, but I also have some electrician friends who are not in the union, but are very good at their trade. The quality of an electrician depends upon the experience and training he has and how much pride he takes on knowing that he has done a safe, workmanlike and quality electrical installation. No matter what the situation an electrician must put the safety of himself, and of the people and property around him first.
 Most areas have different qualifications for obtaining a license. To find the requirements in you state 
Click Here.
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When is it time to call an electrician?...
 When you are resetting circuit breakers or changing fuses to often. When you turn on your air conditioner and the lights dim in the room. When your lights flicker or go on and off. When you can smell electricity burning. When you have six electronic devises going into one outlet in back of your television. When you have receptacle outlets overburdened by multi-plug strips. When a three-prong plug needs a two-prong adapter. If you have to run extention cords to plug in electrical devises.
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How do i find a good electrician?...
 Before we start, remember you are the one paying for the service, and as long as the work is done up to code, you can have what you want.
 Another way to protect yourself is never pay the full amount of the work to be done up front. If the electrician demands money before he starts do not give more than ten percent. Always hold some back until the job is complete.
  It will be hard to get large contractors to do the smaller jobs at a reasonable price. There are many excellent electricians in classified ads,or yellow pages. Do your homework,The first thing you do is make them show you their license. Then be sure they are insured . If you could get one that is bonded (FAQ-4) would definitley be a plus. And always make sure you make them get a permit so their work can be checked by the local wire inspector. Electricity is not something to fool with, be safe.
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What is a bonded electrician?...
 A bond is an insurance policy for which the contractor pays a premium. It guarantees that the contractor will meet his obligations in a satisfactory manner. Failure to do so should result in the payment of compensation by the bonding company.There are three types of bonds payment bond, performance bond and bid bond.
  Being bonded could be like getting an insurance policy that the job 1: will be completed and 2: will be done properly. Larger commercial and almost all government jobs will require that all contractors and sub-contractors be Licensed, insured, and bonded. If you can find a bonded electrician you have a good chance the job will be done properly.
 One of the problems is depending on the cost of the job, the fees a bonding company charges could be high and this may be passed on to you the customer.
 Actually the quality of any good electricians work should be guaranteed until he or she dies. If you do have a problem with faulty work with any bonded contractor, try to get the name of the agent who put out the bond for this particular job.
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What size service do i install in my home?...
 Most states call for 100 amps minimum.But with all the new electronic devises, air conditioning and electric heat. I would suggest 200 amps especially in new homes. This also gives you some space for future additions. This is not a job for an unlicensed person to attempt. In most cases it involves replacing everything from the service loop (this is the wire that extends from the top of your meter to the utility tie in ) up to and including the main panel.
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Where do you put G.F.I.'s?...
Any bathroom or garage outlet within 6' of a sink must be GFCI protected. The code also requires all kitchen outlets for countertop use to be GFCI protected. GFCI outlets must be installed in any area where electricity and water may come into contact, including basements, pools, spas, utility rooms, attached garages and outdoors. At least one GFCI outlet is required in an unfinished basement and for most outdoor outlets.
  The are two types of GFCIs in homes, the GFCI outlet and the GFCI circuit breaker. Both do the same job, but each has different applications and limitations.
 The GFCI outlet is actually a replacement for a standard electrical outlet. A GFCI is not dependent of a ground to function. It does not measure shorts to the ground, it measures the current difference between the hot and neutral wires. A sudden difference of 5 ma. or more, indicating that there is another path for the electricity to flow through will trip this device. The only downside to this is there may be some nuisance tripping. But the newer models seemed to have corrected this somewhat. It protects any appliance plugged into it, and can also be wired to protect other outlets that are connected to it. The GFCI circuit breaker controls an entire circuit, and is installed as a replacement for a circuit breaker on your home's main circuit board. Rather than install multiple GFCI outlets, one GFCI circuit breaker can protect the entire circuit. There is a test button and a reset button on these units. If you press the test button the reset should pop out. To reset just push the reset button in. You can learn more how these work by going to the next FAQ.
 Not a good idea to put lights on GFCI. protected circuits so you aren't left in the dark if the circuit trips. Generally, equipment such as refrigerators, freezers and sump pumps that cannot go without electrical power for an extended period of time without causing costly losses or property damage should not be placed on a GFCI. protected circuit. GFCIs are very sensitive and are subject to nuisance tripping. GFCI receptacles don't last outdoors even under the best of conditions. Be sure to test the device using the "test" button before you use one.
As of January 1, 2002, NFPA 70, The National Electrical Code, Section 210-12, requires that all branch circuits supplying 125V, single phase, 15 and 20 ampere outlets installed in dwelling unit bedrooms be protected by an arc-fault Circuit interrupter. Eventually they will be in more areas but the bedroom is a good place to start.
 The AFCI (Arc Fault Circuit Interrupter) breaker, will shut off a circuit in a fraction of a second if arcing develops. The current inside of an arc is not always high enough to trip a regular breaker.
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Can you use a G.F.I. in an ungrounded outlet?...
 The N.E.C. allows a G.F.C.I. to be used in an outlet with a two wire ungrounded cable, but this might not be that great an idea for several reasons.
 First: The ground lug on a G.F.C.I. receptacle might give the false impression that the outlet has a grounding wire.
 Second: The surge surpressors used for computers and other electronic equipment require a properly installed grounding wire to work correctly.
 There are several other ways to ground outlets. Here is a couple of them. First...Find out if the metal box that holds the receptacles has a proper ground, if it does you can either run a pigtail from the threaded screw in the box to the ground on your receptacle, or install a self grounded type receptacle. Second...And possibly the best and safest way is to run grounded cable back to your panel for each branch circuit. Whichever way you decide to go, these outlets should be grounded for your own safety.
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How much should i attempt on my own?...
 This will not make me very popular but, without a license, not very much. At the present time most states allow you to do whatever you want in your own home. But doing electrical work yourself is a gamble. How much are you willing to risk to save money. There is a reason it takes so much training to become an electrician. Don't take electricity lightly, even the smallest job could be a safety hazard. Why take a chance. Get a professional to do this work.
Also In some states the homeowner can pull his own Electrical permit for work in his single family home, what he does not know is that in case of damage or fire caused by his work, his homeowners insurance will not pay, they will only if the work is done by a licensed Electrical Contractor. You should check with your homeowners Insurance Co., and they should sign a document or something to this effect to acknowledge this when they pull a permit.
 Do not take electricity lightly. The most dangerous time is when you tell yourself. This is easy. I can do it myself. Why should i get an electrician? Than when you don't remember where all those wires went, or your hair is standing straight up, you say to yourself. Well maybe we better call someone to straighten up this mess. Now it will cost you double what you thought you were going to save in the beginning.
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Do i need to spend all this money?...
 Shop around.If you want something done ask the price first. Get an estimate before the job is started.If they don’t want to give you an answer go somewhere else. I know it cost a lot money but find out what an eletrician has to go through to get his license and the chances he takes while working on electricity, You will understand why they charge so much.
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How many convenience outlets in each room?...
 In every kitchen, family room, dining room, living room, parlor, library, den, bedroom, or similar room or area of dwelling units, receptacle outlets shall be installed so that no point along the floor line in any wall space there is more than six feet, from an outlet in that space. This is to prevent the use of extension cords. Outlets are usually placed about 18 inches above floor level. Switches usually go about 48 inches from floor level. For convenience outlets each single receptacle in a single branch circuit is usually figured for 1.5 amps, duplex outlets for 3 amps in estimating total amperage for that circuit. Air conditioners should be on a single dedicated circuit.
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How should outlets be installed in a kitchen area?...
 All 15 and 20 receptacles installed within 6 feet of a kitchen sink or wetbar shall have G.F.C.I. protection. Receptacles in a kitchen used to serve counter tops should be supplied with at least two 20 amp branch circuits, for small appliances. Each fixed appliance (refrigerator, stove, dish washer) shall have its own dedicated circuit. On counter tops 12 inches or wider a receptacle shall be installed so that there is no mare than 24 inches between outlets. Receptacles outlets installed to serve island counter tops shall be installed above, or within 12 inches below the counter top. There shall be no more than 24 inches from center line of counter top. No receptacle shall be installed face up on a sink counter top.
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Where do you install smoke detectors?...
 Here is some information on where to install smoke detectors. Some local codes may vary, so check first.
 Wall-mounted units should be mounted so that the top of the detector is 4 to 12 inches from the ceiling. A ceiling-mounted detector should be attached at least four inches from the nearest wall. In a room with a pitched ceiling, mount the detector at or near the ceiling's highest point. Place the detector near the bedrooms, within 15 feet of sleeping areas. The National Fire Alarm Code, developed by NFPA, requires a smoke detector in each sleeping room for new construction. it is a good idea to place one on each level of the house. Also additional detectors can be installed near the furnace and washer and dryer. Because smoke rises, mount detectors high on a wall or on the ceiling. Place them in an area away from air vents The basement ceiling near the steps to the first level is a good location. But don't install the detector at the top of the basement stairs where there is a closed door, dead air space near the door may prevent smoke from reaching the detector.
 There is more to checking a smoke detector than just pushing the test button. Dust and even small insects can sometimes block a photoeye type or ionization type of smoke detector. They also should be cleaned periodically. Dont go to long before changing batteries. If they are hard wired make sure they have a battery back up. Smoke detectors should not be taken lightly. They could save your life.
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How Safe is Aluminum wire?...
 Aluminum wire is still approved by the N.E.C. But this on the assumption that everything will be done perfect. Having said that i would like to give a little advice on using aluminum wire when you are building a new home. For the sake of saving a few dollars, it is not worth the safety hazard you face when using this wire. This is not only my opinion but the opinion of many others in the trade. Many times i have been called to repair corroded connections using this wire. Most of the time the aluminum wire had to be replaced with copper. One other piece of advice, Before you consider buying a home with aluminum wire you might want to check with the insurance company. Some of them may refuse to insure a house with aluminum wire.
 There are a lot of homes that have been wired with aluminum wiring and it would not be financially possible to rewire the entire house or service. There are a few things you can do to make sure that the wiring is not becoming a problem. You should be on the lookout for devices or lighting going on and off. Breakers or outlets overheating. Have the main panel checked for corrosion or loose connections. When adding copper devices or wire to aluminum make sure the person doing this work is familiar with the proper procedures for doing this type of wiring. A little preventative maintenance can go a long way in preventing future safety hazards.
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How can i save money on my electric bill?...
 The most electricity in your home is used by Electric Heat, Air conditioners, Electric Hot Water and your Electric Dryer. You could help by getting an automatic thermostat. Those long showers are nice but there costing you extra money. Do you really need to run that dryer that often? One other thing that could cause a problem would be a bad breaker or loose connections at the breaker.
 Depending on what part of the country you live in, heating and cooling are the largest contributors to most household energy bills and are the best places you can look to save money. After making sure your home is well insulated, make sure your heating and cooling systems are running efficiently and central systems are checked annually.
 To keep equipment running efficiently, keep heating and cooling air ducts clean and outdoor equipment free from dirt and other debris.
 A balanced load in your electrical panel. Also the homeowners habits of electrical use. What is on? At what times? Can save money on your electric bill.
How to read the utility electric meter!
 Most electric meters are clockface, which means they use clockfaces instead of actual numbers. There are usually five clocks. Reading the clock faces from left to right, note the number the hand is pointing to. If the hand is between two numbers, note the lower number. If the number on each meter left to right was 1 2 3 4 5. Than your meter read is 12,345 KWh. And the next month it was 1 2 4 4 5, you would have used 100 KWh.
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Should the ground lug on a receptacle be up or down?...
 There are good arguments for both sides of this issue. The reason i chose to take this side is because of having to replace some receptacles because they were shorted out with the ground lug down. That is why i believe you are better off having it up. This way if the plug is not inserted all the way, or becomes loose, it would give some protection against falling metal objects going across the live and neutral blades and shorting them out. They would land on the ground lug of the plug first. One of the reasons for putting the ground lug down is, there is less of a chance that the plug will come loose, and disconnect the ground connection.
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How is electricity produced in a circuit?...
 There are atoms in the air, these atoms contain electrons. To produce electricity you need a force to move these electrons. There are several ways to produce this force, the most common being magnetism which can be produced by generators. This force is called E.M.F. (ElectroMotive Force) . As conductors are passed through a magnetic field a voltage (emf) will be produced in each conductor. This voltage will produce the necessary pressure to move the electrons. The movement of these electrons is called electric current or amperage. Thus you have voltage and amperage which along with resistance (the load) make up an electric circuit.
 Electricity is one of the great assets we have. Just think for a minute how you feel when your power goes off for a short period of time. Harnessing electricity has improved just about everything in our lives. Electricity begins mostly at large dams and waterfalls, and some nuclear plants. The constant flow of water is used to turn large generators, which through magnetism produces electricity. The electricity is than sent to power lines at extremely high voltages. When it reaches your home from sub stations, it goes through a step down transformer, ( these are the large metal units you see on the telephone pole ) and produces the correct voltage needed for your home.
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What is the neutral wire...
 The utility transformer feeding your service is 240 volts single phase. In order for you to have 120 volts they need to split the voltage with a center tap at the transformer called the neutral. This is the third wire brought to the neutral buss in your main panel. This wire is also referred to as the grounded conductor. The grounding conductor is the wire attached to the water main or electrode and than to your panel and is used to ground your electrical devices. The neutral or white wire in your circuit is the return for the live feed from your circuit and is bonded at the main panel to the grounding conductor so that any stray currents caused by equipment faults will go back to the utility transformer.
 The grounding of electrical devices is possibly the best safety precaution you can take. Grounding helps to prevent accidents to persons and damage by fire to property.
 An equipment or conductor-enclosure ground refers to connecting the non-current-carrying metal parts of the wiring system or equipment to ground. This is done so that the metal parts with which a person might come to contact is at or near ground potential. With this condition there is less danger that a person touching the equipment or conductor enclosure will receive a shock. Also metal conduit, raceways, and boxes may be in contact with metal parts of the building at several points. If an accidental contact occurs between an ungrounded conductor and its metal enclosure, a current may flow to ground through a stray path made up of sections of metal partitions, piping, or other similiar conductors.
  If the equipment is grounded, the resistance of the path through the grounding conductor will usually be much less than the resistance through the stray path, and much current will flow through the stray path. Sufficient current will usually flow through the grounded path to blow the circuit fuse or trip the circuit breaker and thus open the circuit. On the other hand if the equipment is not grounded sufficient current will flow through the stray path to be a shock hazard.
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Why isolate the neutral in a sub panel?...
 The neutral is only bonded to ground at your service panel. At all other points throughout your house, there is no connection between the bare (or green) grounding conductor and the white neutral conductor. Under normal conditions, the grounding conductor carries no current. No current means there is no voltage drop along it, therefore anything "grounded" to this conductor is at the same potential (voltage) as ground. If you bond the neutral and ground at the sub panel, than stray currents from the neutral return could go thru the equipment ground on the electrical devices fed from this sub panel. If you isolate the neutral and ground at the sub panel, than any currents would go back to the main panel, where they should be bonded, and go to the service ground.
 If you install a sub panel outside the building from the main panel, than you will need to drive a ground rod at this panel. A single branch circuit run to another building is not considered a sub panel.
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What is a ground rod?...
 A ground rod is a metal shaft used for grounding. With plastic pipe now being used for water systems these rods are being used for services and other devices to be grounded. These rods are to be driven in the ground at least 8 ft. These rods when made of iron or steel shall be at least 5/8 inches thick. Non ferrous rods should be free of paint or any other non coductive material shoud be listed and not less than 1/2 inches thick. Most codes call for a ground system of 25 ohms or less. While, as a practical matter, you can't get to zero ohms, you certainly can get to 25 ohms if the ground rods are properly installed. To verify the resistance of ground, it is most often tested with instruments using the fall-of-potential method by a trained technician.
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What size generator should get?...
 Generators should be installed by qualified electricians. Most generators are rated in watts. The formula for watts is Watts=Volts x Amps. If you you have a 120 watt bulb at 120 volts you would have one amp. If you were to run 25 100 watt bulbs you would need a 2,500 watt generator. Motor circuits such as circulating motors for heat and compressors for refrigerators must be calculated differently. It takes about three times the current to start a motor. Most motors have the amperage rating on the name tag. If the motor has a nameplate rating of 3 amps you might want to add 9 amps on your generator calculations. Also because most generators may run over a period of time you may not want to run at full capacity. About 80% of the wattage rating of your generator would be the way to go.
 There are a few things to consider when getting a generator.
The cost involved.
The addition of a transfer switch.
A room outside to put the generator.
You need to maintain a generator regularly, including running it every so often so that it will work when the power goes out. Also check while it is running.
Adding fuel. The generator will need to be shut off when adding fuel. Anytime you have fuel and electricity together there is a danger.
If you are getting a generator just to run your computer , you might be better off with a laptop or a UPS. system.
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Why put transfer switches on generators?...
The only proper and most safe way to run a generator is with a transfer switch. These switches should only be installed by an electrician.Transfer switches have three selections. off...and utility. It prevents you from having the generator and the utility power on at the same time. Which would mess up the wiring in your home. And when installed properly will prevent a backfeed to the utility lines which could prove fatal to lineman working. The utility transformer is a stepdown into your home but becomes a stepup when fed the other way.
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What is power factor?...
 Power factor is the ratio of true power or watts to apparent power or volt amps. They are identical only when current and voltage are in phase than the power factor is 1.0. The power in an ac circuit is very seldom equal to the direct product of the volts and amperes. In order to find the power of a single phase ac circuit the product of volts and amperes must be multiplied by the power factor. Ampmeters and voltmeters indicate the effective value of amps and volts. True power or watts can be measured with a wattmeter. If the true power is 1870 watts and the volt amp reading is 2200. Than the power factor is 0.85 or 85 percent. True power divided by apparent power. The power factor is expressed in decimal or percentage. Thus power factors of 0.8 are the same as 80 percent. Low power factor is usually associated with motors and transformers. An incandescent bulb would have a power factor of close to 1.0. A one hp motor about 0.80. With low power factor loads, the current flowing through electrical system components is higher than necessary to do the required work. This results in excess heating, which can damage or shorten the life of equipment, A low power factor can also cause low-voltage conditions, resulting in dimming of lights and sluggish motor operation.
 Low power factor is usually not that much of a problem in residential homes. It does however become a problem in industry where multiple large motors are used. Power Factor Correction Capacitors are normally used to try to correct this problem.
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What is the National Electric Code?...
 The National Electric Code is a document sponsored by the National Fire Protection Agency. It is a book electricians will have to learn before obtaining there license. Most electricians can find articles easily because they have spent so much time studying the book. For a person looking thru the book for the first time, it would be easier to use the index in the back of the book. There are so many applications for each wiring job, it would be hard for the NEC. to list all of them. An electrician must use his or her own judgement when wiring, without going below the minimum safety standards set forth by the NEC.
 The National Electric Code is a guideline for electricians, electrical contractors, engineers and inspectors. Most states require a permit and inspection. While going by the NEC will not guarantee safe electrical installations, it is the best guide available. Every state may differ slightly in their requirements for inspection and code compliance. You should check with the local wire inspector before having any wiring done. In most areas (city and town) the local wire inspector is The Authority Having Jurisdiction. The authority having jurisdiction for enforcing the code will have the responsibility for making interpretations of the rules.
  For more details on the N.E.C. try
 Mike Holts Web Site.  N.E.C. code books can be purchased at most electrical supply stores.
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How can you stop static electricity?
  An electric charge is produced when two pieces of material are rubbed together, such as silk and a glass rod, or when you comb your hair. Did you ever walk across a carpet and get a shock when you touch a metal doorknob. Your shoe soles built up a charge by rubbing on the carpet, and this charge was transferred to you and was discharged on the knob. These charges are called static electricity, and results when one material transfers its electrons to another. Even materials known as insulators (glass and rubber) can build up charges of electricity. Static electricity occurs quite often when there is low moisture and the weather is cold and dry. It stands to reason replacing the moisture would be a big help. Grounding is the best way of removing static electricity, but is not always practical. Placing humidifiers in heating systems can help. Even sometimes just placing water next to heating ducts can help. Moisture in the air will be absorbed by the carpet fibers.The moisture in the fibers will help to dissipate the electrical charge. There is also antistatic sprays that can be used. Newer carpets are being made with antistatic materials already in the fiber.
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What causes lights to dim?
  If your lights dim when an appliance (fridge, air cond, etc.) comes on, check to see if the lights are on the same circuit with the appliance. Most fixed appliances (fridge, air cond, etc.) should be on a dedicated circuit back to the main panel. These devices draw quite a bit of current in the first second or so when they first start up. If all the lights in your house are dim all the time or periodically, the problem could be at the local utilities substation, transformer or their service feed coming into your house. This is one of the first thing you might want to have checked.
  Your lights could dim if the wiring in your house is not large enough, it will have too much resistance. When a large current is present in the wire, there will be a significant voltage drop, leaving less voltage available to your lights. If the light in your house dim and also get brighter it could indicate a lot more serious problem, a loose, broken or corroded neutral wire. Electricity is usually delivered to your home via three wires, two hot and one neutral. Each 120 volt circuit taps one hot wire and the neutral. A 240 volt circuit taps both hot wires. If the neutral wire comes loose, there is a risk that the 120 volt circuits will, at least momentarily, be supplied with 240 volts. The problem could be with the utility company connections, the main panel, or the branch circuits.
  For the three-wire cable, two of the wires will insulated. They are called the "hot" wire (black) and the return wire (white). The third wire is typically a bare or green covered copper wire. The 120 VAC potential will be found on the hot wire, while the return wire should be close to zero potential. Current will flow from the hot wire to the device and return along the return wire. No current flows without a return path. There should always be the same current flowing in the return as there is in the hot wire.
  But the return is not always at zero potential relative to your local ground. For safety, there should always be a local ground. This is the purpose of the bare copper wire. It should be connected at one end to a conductor that is buried into the ground. All metal electrical casings and electrical outlets should be connected to this wire. If you are burning bulbs to frequently you also might try using lower wattage bulbs. A 40 W bulb has a higher resistance than a 100 W bulb. Both bulbs will have the same voltage, the 100 W bulb must have more current. And that means the 100 W bulb must have a lower resistance. So the filament for the higher resistance 40 W filament must be heavier or have a smaller cross section. There is also a rough service buld that is made with a heavier filament. The best bulb on the market today is the CFL (Compact Fluorescent Lights) (Philips, Sylvania). These bulbs may cost 10 to 15 dollars, but will last about 10,000 hours.
  Newer light fixtures require that the temperature rating of the wire feeding these fixtures be at least 90 degrees C. This is the temperature rating for these light fixtures. It's important that the temperature rating for the wiring feeding these fixtures match or exceed the rating for the fixture. If the temperature rating of the wiring is lower than the 90 degrees C. required, the insulation around it becomes brittle and may break away. This allows arcing between bare wires, which causes heat that melts the fixture and could be a fire hazard.
 Look for the letters NMB on the jacket of the wire. The NM means nonmetallic sheath cable (Romex) and the B suffix means that the cable's conductors are rated for a maximum operating temperature of 90°C 194°F. We can assume that wiring made prior to 1984, without the B suffix, is rated at 60°C 140°F. This is the type of wiring found in most older homes that were built before 1982.
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What are harmonics?...
 With more and more electronic devices being used the term harmonics comes into use. Harmonics should be taken seriously but they are not the only cause of your electrical problems. If you have tried everything and you are still having problems and you have a lot of electronic devices it is something to think about. Any distortions in the voltage or current wave causes harmonics. We can give you a lot of technical explantions on what harmonics are but the intention of this website is to help everyone understand electrical terms not cause more confusion. In fact a lot of people (including myself) in the electrical trade exactly not sure how harmonics effect electrical circuits.
 These harmonic currents create heat. This heat over a period of time, will raise the temperature of the neutral conductor, nuisance tripping of circuit breakers, overvoltage problems, blinking of Incandescent Lights, computer malfunctions. Among the electrical devices that seem to cause harmonics are Personal Computers, Dimmers, Laser Printers and Electronic Ballast. This is not to say that harmonics will cause all these problems, only that it is possible.
 You can somewhat prevent these problems by using a dedicated circuit for electronic equipment. Also on a branch circuit use an isolated ground wire for sensitive electronic and computer equipment. A more expensive way is to rectify and filter the mains thus effectively removing all low frequency harmonics including the fundamental. Oversized neutrals is another possible means to prevent overheating of this wire. In power distribution systems electricians are usually interested in measuring the current, thus a "true-RMS" (effective or equivalent heating value) current measuring clamp-on meter is normally used.
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What is an AFCI?...
 Starting January 1, 2002, The National Electrical Code , Section 210-12, requires that all branch circuits supplying 125V, single phase, 15 and 20 ampere outlets installed in dwelling unit bedrooms be protected by an arc-fault Circuit interrupter. Eventually they will be in more areas but the NEC selected to require them on bedroom circuits first because a CPSC study showed many home fire deaths were related to bedroom circuits.
 The AFCI (Arc Fault Circuit Interrupter) breaker, will shut off a circuit in a fraction of a second if arcing develops. The current inside of an arc is not always high enough to trip a regular breaker. You must have noticed a cut or worn piece of a cord or a loose connection in a junction box or receptacle arcing and burnt without tripping the regular breaker. As you can guess this is a major cause of fires in a dwelling.
 There is a difference between AFCIs and GFCIs. AFCIs are intended to reduce the likelihood of fire caused by electrical arcing faults; whereas, GFCIs are personnel protection intended to reduce the likelihood of electric shock hazard. Don't misunderstand, GFCIs are still needed and save a lot of lives.
 Combination devices that include both AFCI and GFCI protection in one unit will become available soon. AFCIs can be installed in any 15 or 20 ampere branch circuit in homes today and are currently available as circuit breakers with built-in AFCI features. In the near future, other types of devices with AFCI protection will be available.
 If a GFCI receptacle is installed on the load side of an AFCI it is possible for both the AFCI and the GFCI to trip on a fault if the current exceeds the limit for both devices. It is also possible for the AFCI to trip and the GFCI to not trip since the two devices could race each other. However, in no case is safety compromised.
 At first the cost for AFCI will be high. Expect to pay between $70 and $150 for each AFCI. The cost is expected to drop as much more are ordered.
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This page was created 1/3/98.