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Mr. Electrician

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Licensed Electrical Contractor

Arc Fault Circuit Interrupters

Dear Mr. Electrician: Why am I required to have my brand new house wired with Arc Fault Circuit Interrupters?  They cost much more than standard circuit breakers. Answer: Arc Fault Circuit Interrupter type circuit breakers and receptacles provide an additional level of protection against fires.  Electrical arcs generate heat and sparks.  If combustible materials are nearby, a fire could erupt.  Arc Fault Circuit Interrupter circuit breakers protect us from potential fire starters that we cannot see.  Many residential homes have wood frame construction.  The electrical switch and receptacle boxes in the walls are attached to wood framing members.  The electrical wiring runs through the wood framing. Wood is a combustible material. An electrical arc can be caused by lightning of course and your grounding electrode system, if it is in good condition should handle that.  However other causes of arcing are usually not as obvious until some damage or a fire takes place.  For instance, an electrical receptacle with a loose connection may be fine until one winter you decide to plug an electric heater into it.  The heater uses a lot of current to keep you warm.  With the extra load on it, the loose connection that was fine for a few years now arcs each time the heater is on.  This can cause damage to the receptacle, the wiring in the electrical box and wall, and even the heater plug and in addition the potential for fire is high.  If combustible materials are near by such as drapes and curtains, bedding or even furniture, a fire can start whether you are home or not. Other Issues That Can Cause Arcing and Heat: - Loose or broken plugs or cords on appliances and lamps. - Nicks in the house wires and/or the wire insulation that occurred during the original        construction or a renovation thereafter. - Worn out electrical receptacles that do not hold the plugs in tightly. - Frayed insulation on appliances and lamps. - Worn electrical switches. - Very old electrically powered appliances where the internal electrical insulation has degraded. Another possibility for wiring getting damaged is from a major redecoration or renovation project where the old existing wiring is disturbed.  A small unnoticed problem that occurred during the original renovation may not manifest itself into a major hazard until months or years later.  Existing wiring is best left alone in older houses.  Like everything else in a house, wiring ages whether you use it or not.  However this does not mean that you should replace every wire in your house after so many years.  The wiring should last the life of the house as long as it is not disturbed and minor maintenance is performed every few years. Maintenance such as tightening all connections in the circuit breaker panel and at all switches and receptacles will help to prevent arcing and heat. Articles 210.12, 440.65, 550.25, and 406.4(D)(4) in the National Electrical Code pertain to the requirements for arc fault protection.  Replacement receptacles must be tamper resistant arc fault receptacles. Dual Function circuit breakers and receptacles are...

Homeowner Purchases Materials For the Contractor

Dear Mr. Electrician: I want to get a bunch of electrical projects done around my house. I talked to several licensed electrical contractors about the work.  I told each one that I would pay for the materials and that they should just figure on furnishing labor and tools.  None of the electrical contractors were receptive to my plan.  Why do you think that was?   Are materials a big profit maker for electricians? Answer: From time to time I get that request from customers.  I am always willing to work with someone to help them save a few bucks, but I think in this instance you are better off letting the contractor provide the materials. On a bid job such as yours the profit on materials for a contractor is low.  If the contractor wants that job he/she will try and get the lowest prices possible on materials from his or her suppliers.  Marking up the materials will raise the bid price.  As part of the bid the contractor will need to cover the cost for picking up the materials and delivering them to the job site.  This is something that you can offer to do for the contractor which will save him or her time.  The order can be called in to the supply company by the contractor and you can go and pick the materials up.  However in some instances a truck will be required for larger items such as conduit. A problem with this arrangement is that sometimes the supply company makes a mistake and items are omitted from the original order.  Also some items could be out of stock.  You will not know what is missing or what could be substituted until your electrical contractor shows up to do the work. Offering to buy the materials and bring them to the job doesn't work well for the homeowner or for the contractor.  I can speak from my own experiences on this matter. Each time that I agreed to this arrangement it actually took longer to complete the job and cost the homeowner more money. In a typical homeowner buys material situation I would have to take the time to write a neatly written or a typed detailed list giving quantities, names, part numbers and descriptions of the items that I need.  I would also give the homeowner names, addresses and phone numbers of a few electrical supply companies in the area.  Normally for myself I would just jot some abbreviated things down on a scratch piece of paper and call in my list to the supply company. After providing the list of electrical materials to the homeowner I would then have to wait for him to go pick up everything in his spare time.  When he had gathered all of the materials I would get a call that everything is ready and I could come over to do the work. I get over to the job site ready to complete it as quickly as possible and find that some key material items that...
One example of an Intersystem bonding termination as required by the National Electrical Code.

Intersystem Bonding Termination for TV and Telephone

Dear Mr. Electrician: How do I ground my telephone and cable TV demarcation terminal blocks? Answer: Your telephone and cable TV service each needs to be bonded to a ground rod or water pipe ground, or both if available.  This is for lightning protection.  If Lightning were to strike the outside cable TV wire and your home has good ground connections, the lightning energy would be channeled directly to earth.  With a poor or non-existent earth ground connection, the lightning will find a way to earth, but that could be a path through your TV, computer, major appliance, even the metal ducts in your house.  That is how things get damaged or fires start.  Click here for photos of one example of a TV and Telephone bonding and grounding on an older house. The Photo above depicts an Intersystem Bonding Termination which is required by the National Electrical Code.  This simple terminal block makes it easy for telephone and cable TV installers to connect their grounding electrode conductor wire to a good earth ground connection.  It takes one large grounding electrode conductor and up to four smaller grounding conductors for cable TV and telephone services.  It is important to have this for lightning protection.  The Intersystem Bonding Termination is required as per article 250.94 in the National Electrical Code.  You should also read NFPA 780 on lightning protection. Something else to consider is the installation of a surge protector.  Read my post on that subject here.

Testing a Dishwasher Appliance for Power

Dear Mr. Electrician: I use my dishwasher for storage and occasional dish washing. Last night I tried to wash dishes, but nothing happened.  There were no sounds or visible indicator lights.  What could be wrong? Answer: An appliance such as a dishwasher usually requires the services of an appliance technician for repair and not the expertise of an electrician.  However at the very least you can check to see that the dishwasher has power going to it. First make sure that the fuse or circuit breaker is not off.  Go to your home's main fuse box or circuit breaker panel and reset the circuit breaker for the dishwasher by pushing fully to the "Off" position and then to the "On" position.  If you don't know which circuit breaker is for the dishwasher, then reset them all.  If you have fuses instead of circuit breakers, replace the fuse for the dishwasher.  Now check to see if the dishwasher is working again. If resetting the circuit breaker or replacing the fuse does not get the dishwasher running again, you will need to look inside of the dishwasher.  Start by removing the bottom front cover to expose the components of the dishwasher.  This is usually accomplished by the removal of a few screws on each end or the pushing of some clips to release the panel.  It is also possible that the bottom cover is just hooked in place and only needs to be lifted up for removal.  The dishwasher owner's manual may have the necessary steps detailed for the cover's removal. You will need to get down on the floor in order to work inside of the dishwasher.  A furniture pad or blanket placed on the floor will make this a little more comfortable.  In the bottom of the dishwasher you should see a small electrical box with a cord or cable going into it.  Use a Non-Contact Voltage Tester and touch the side of the cord or non-metallic cable to see if there is electricity.  The non-contact tester will not work properly with a metal jacketed cable such as Type AC (BX) or Type MC cable. If the non-contact tester indicates that there is voltage on the cord or cable, then you should shut off the power at the fuse box or circuit breaker panel.  Remove the fuses or shut off the circuit breakers until the non-contact voltage tester indicates that there is no power there. With the power to the dishwasher OFF, remove the cover on the small electrical box located on the bottom of the dishwasher.  Double check the wires inside the small electrical box with the Non-Contact Voltage Tester.  If it still indicates that there is no voltage present then disconnect the white and black wires.  Using a pigtail socket with an ordinary working light bulb, connect the pigtail socket wire leads to the cable or cord coming into the dishwasher electrical box.  Be sure to cover the ends with wire connectors so that no bare copper wire is exposed. Now go and turn...

Index

Alphabetically Indexed Site Map of All of the Topics on MrElectrician.TV A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z A About Aluminum Wiring Arc Fault Circuit Interrupters (AFCI) B Basement Wiring Bathroom Fan Repair Buying Electrical Materials C Cat 5 and Cat 6 Wiring Diagram Ceiling Electrical Box is Loose Ceiling Fan Box Installation (Old work) Ceiling Light Fixture with Dimmer Switch - With Photos Ceiling Lights - Recessed in Condo Kitchen - With Photos Coat Hanger Tool Common Mistakes Concentric Knockouts - With Photos Conduit Dimensions Contact Conversion Charts Copalum D Data Wiring Diagram Dimmer Switch with New Ceiling Light Fixture Installed - With Photos Dishwasher Problem Drill and Tap Sizes Chart E Electrical Conduit and Pipe Dimensions Electrical Formulas and Symbols Buying Electrical Materials F Fan Repair, Bathroom Fishing Wires using a Coat Hanger Foreign Workers Fractional Horsepower Electric Motor Diagrams G Generator interlock kit For CH main circuit breaker panel - With Photos Generator interlock kit For GE main circuit breaker panel - With Photos Generator Sub-Panel with Generator Flanged Inlet - With Photos GFI or Ground Fault Interrupting Receptacles Grounding Grounding Telephone and Cable TV H Home Page I Installing a Receptacle Box in the Wall Interlock kit for a generator on a CH main circuit breaker panel - With Photos Interlock kit for a generator on a GE main circuit breaker panel - With Photos Intersystem Bonding Termination Photos J K Knockout Removal - With Photos L Links Loose Ceiling Box Loose Electrical Receptacle M Installation of a Metal Receptacle Box using Madison Bars - With Photos Microwave Oven over-the-range - With Photos Motors, Fractional Horsepower Electric Motor Diagrams N New Dimmer Switch and Ceiling Light Fixture Installed - With Photos O Ohms Law Outlet Box Installation P Phone Wiring Diagram and Color Code Photos Telephone and TV Grounding Pipe Dimensions Privacy Q R Range - Over-the-Range Microwave Oven - With Photos Installing a Receptacle Box in the Wall Installation of a Metal Receptacle Box using Madison Bars - With Photos Recessed Ceiling Lights in a Condo Kitchen - With Photos Replace Loose Ceiling Box Replace Electrical Receptacle Replace Old Style Ceiling Pancake Junction Box S Safety Surge Protectors T Tap and Drill Bit Sizes Chart Telephone Color Code Wiring Diagram Three Way Switch Wiring Telephone Grounding Photos TV Grounding Photos U V W Wiremold Used to Power a Garage Door Opener - With Photos X Y Z A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z
A dirty bathroom fan and grill. Bathroom fans that share a home with pets tend to get this amount of dirt, dust, and dander.

Bathroom Fan Repair

Dear Mr. Electrician:  The exhaust fan in my bathroom stopped working after making some exceptional noise for several weeks.  Does the fan need to be replaced or can it be repaired?  Is this something that a homeowner can do? Answer:  In many homes it is possible that a homeowner can fix hers or his own bathroom exhaust fan.  Quite a few fans were manufactured for a simple and fast installation by the original installer.  Consequently the repair can be almost as simple. The key to a successful bathroom fan repair is getting the correct replacement parts.  Many are still available, but identifying the correct parts can be a chore. When your bathroom fan was manufactured, a model number was labeled inside of the housing or the fan motor support bracket.  (Note: This is not the number on the motor itself)  The model number may be stamped into the metal or there may be a label glued inside somewhere.  I remember having to repair a customer's fan that did not have a model number anywhere.  I recognized the brand and called the customer service telephone line.  I described the fan and the person at the factory was able to give me the correct model number and also sold me the correct parts.  After I installed the new parts I made a point of writing the model number inside of the housing with a paint pen. I wrote a book about repairing bathroom fans.  "Almost Everything You Need to Know to Repair a Bathroom Exhaust Fan in Your Home" is available as a free download by clicking here. Replacing the bathroom fan motor can be just a few simple steps that a novice can complete.  You need to find the correct replacement parts.  My book can help with that. I also suggest tools that may be needed, in addition to safety information. In my book I list the contact information for most of the bathroom exhaust fan manufacturers and other suppliers of bath fan replacement parts. As an electrician I have installed, replaced, and repaired many models of bathroom fans. There are certain factors that contribute to the optimum performance of a bathroom exhaust fan.  There are also a few things that a homeowner can do to maintain a bathroom fan and keep it running for as long as possible.  One important tip is to be sure to obtain the correct replacement parts when attempting a repair. Many bathroom exhaust fans can be serviced by a novice with a few simple steps. With all of the fans that I have repaired, one common problem was prevalent in all of them. "Almost Everything You Need to Know to Repair a Bathroom Exhaust Fan In Your Home" A Total of 19 Free Easy-to-Read Pages divided below: Safety - When you work around your home, you take some of the same risks as a professional.  You need to protect yourself. Diagnose - Things to check for optimum bath fan performance. Identify - The correct model number and specifications for your fan. Repair - How to repair your bath fan. Prevention - Get the longest...
Concentric knockouts (KO's) ready for removal.

Removing Concentric Knockouts from an Electrical Panel

Dear Mr. Electrician:  What is the best way to remove the pre-punched concentric knockouts in an electrical circuit breaker load center panel without loosening the remaining outer rings? Answer:  Remove them very carefully.  If you look closely at the way the knockouts are stamped on the electrical panel you will see that they alternate between being punched in and being punched outwards.  You could start with the smaller center KO first, but I usually go with whatever is easier and most convenient for each job.  I use a hammer and an old screwdriver for making the first punch.   Begin the removal by banging it in the direction that it was pre-punched from the factory.   Depending on the manufacturer, some concentric knockouts are easier to remove than others. Once you get it started by hitting with the screwdriver you need to twist it or knock it forth and back a few times to loosen it up.  If you have a good pair of diagonal pliers or a pair of BX Cutters you can sometimes get in there and cut one or more of those welds or the ring itself.  Just don't try to get it real fast.  Be patient and work it out.  You will feel the knockouts get loose as you move them forth and back. For subsequent rings sometimes you can use your pliers to carefully pry the ring halves until they are up enough to squeeze them together and then move the pliers forth and back parallel to the anchor point until it breaks off.  If you try to rock in the other direction it will tend to twist the next ring up.  Just keep removing the rings in the direction that they were punched and you should be fine. In a situation where the electrical sub-panel is recessed in a wall, you can use a long thin screwdriver and stick it between the edge of the wall and the edge of the panel to apply a little pressure on one of the rings from the outside to get it started. Each electrical manufacturer's concentric knockouts are different in strength and ease of removal.  Sometimes they pop out too easily and you have a much bigger opening then you need.  Fortunately there are Reducing Washers available in all trade sizes, made to transition from the larger opening down to the size that you need.  If you punch out the wrong knockout, it can be sealed up again using a Knockout Seal.  Both of these items can be purchased online or at almost any local electrical supply company.
A microwave oven installed under a cabinet.

Installation of a Microwave Oven Over a Stove

Click here to see more photos of an outlet box being installed using Madison Bars.  
The hole cut-out ready for a metal receptacle box. I held the face of the electrical box against the wall and penciled an outline to follow with my Drywall Saw.

Electrical Receptacle Box Installation in an Existing Wall Using Madison Bars

Click here for my post about installing an electrical receptacle.
A metal outlet box installed on wood lathe using small wood screws.

Install an Electrical Receptacle Outlet in an Existing Wall

Dear Mr. Electrician: I want to install an outlet on a dedicated circuit for my window air conditioner.  I've got it figured out how to run the 12/2 NM-B cable from the circuit breaker electrical panel in the basement up through the wall under the living room window.  How do I install an electrical receptacle box in the wall that will contain the wire and support the receptacle? Answer: Assuming that you will be drilling a hole from below and fishing the cable into the outside wall, the best place to cut a hole and mount a box is adjacent to a wall stud.  That way the box can be screwed through its side directly to the wood to make it solid. Locating a wall stud may not be that easy however.  I usually use an existing wall receptacle or switch as a reference.  If they were installed at the time that the house was built they are most likely mounted on wall studs.  I would remove the wall plate from the existing receptacle or switch and poke a long thin screwdriver to the right and to the left of the electrical box.  I would also push the box a little to see if it pivots.  Usually the side that is mounted to the stud will not move. Some of the applicable "National Electrical Code" references for this job are: Articles 210, 210.12, 250, 300.4, 310, 314, 334, 406.4(D)(4), 406.12, 440.6, 440.13, 440.31, 440.32, 440.62, 440.62(C), 440.63, 440.65. In newer homes with drywall I also look for indications of nail holes that were spackled over to find studs.  After I have a few studs located I measure over to the area where I would like to cut a hole for a receptacle.  In most home construction the wall studs are sixteen inches apart, but that is not always the case.  Sometimes wall studs are twenty four inches apart.  On some taller condominium buildings I have found the outside walls to have studs at twelve inches apart.  Measurement is from center to center and I always measure twice.  If I am lucky my measurement will correspond with a spackled nail hole which confirms that I have a stud.  Tool and material list below. On older homes with plaster walls it is not as easy to find a wall stud.  There are no indications of nail holes and sometimes outlets have been installed in the baseboard molding.  The use of electronic stud finders on plaster walls can be limited because of the inconsistencies of the old plaster keys and wood lathe.  In this situation the window itself may be the best indicator.  There should be at least one stud on each side of the window that goes from floor to ceiling. For walls with regular drywall you have a choice of using a one gang plastic old work box or a 2"x3" metal old work box.  Consult article 314 and table 314.16(A) and table 314.16(B) in the National Electrical Code for the proper size box for the...