Electrical wiring methods and procedures

Electrical wiring methods and procedures

BECOMING ACQUAINTED with basic Electrical wiring methods and procedures will enable you to tackle a variety of electrical projects. In many cases, these include running cable through walls or between floors, connecting receptacles and switches to the system, and installing new circuits the subjects covered in this Article. For the basics, including an explanation of the workings of the home electrical system and the tools and equipment used in residential wiring, review the material.

Basic Circuitry In Electrical Wiring Methods And Procedures

Charting Circuits ,Whether working with fuses or circuit breakers, you must know which switches, receptacles, fixtures, or equipment are on the circuits they control. You must also know how they work. There are many types of fuses and circuit breakers, each with its own function. The purpose of fuses and circuit breakers is to protect the wiring not the appliance. Keep this in mind as you chart circuits, CITIES verifying that no fuse or circuit breaker has more amperage than the wire it is protecting. The maximum allowable current a wire can carry, measured in amps, is called its capacity.

fuse and circuit breaker capacitor
Fuse and circuit breaker capacitor

While you are inspecting your fuse box or breaker panel, look for any obvious problems. For example, if you unscrew a fuse from a fuse box, examine both the fuse and its screw shell. (To be safe, first pull the main
fuse) Check the fuse or the screw shell for any damage from arcing or burning.

Once you are certain that there is no dam-age to your fuse box or breaker panel. you may begin to chart your circuits. A plug-in radio will come in handy, as will an assistant, if you can find one. If necessary, you can do the work alone it will just take a bit longer.

CHARTING CIRCUITS

Identifying which circuits service all the receptacles, switches, lights, and appliances in your house takes some time. And it works best if you do it with a helper, so you’ll have to draft someone for the afternoon and expel everyone else so things are quiet. The time and effort you spend on this job, however, are well worth it. By knowing which breaker controls which device, you can quickly turn off power to anything you are working on and avoid the risk of serious shock.

TOOLS & MATERIALS

  • Felt tip marker
  • Stick-on labels
  • Graph paper

1. Before you label anything in your service panel box, make a scaled drawing of every room in your house. Draw the location of all the receptacles, light fixtures, switches, and appliances, and note where all the cabinets and furniture are positioned.

drawing of every room in your house
Drawing of every room in your house.

 

2. Once all the circuits are identified, go to the service  panel and mark which breakers go to which circuits using stick-on labels. Then test each circuit by turning off the power, plugging in a radio (that’s turned on) to any given outlet, and then turning the power on at the panel to see if the radio plays.

circuits using
circuits using

3. If you are working by yourself, adjust the radio to a high volume so that when you turn on the power you can hear from the service panel area if the radio comes on.

 

4. As you go from outlet to outlet, note on your room drawings which ones occupy which circuits. You’ll need help to check if lights and ceiling fans turn on when you switch the breakers.

5. You will also need help from someone to check any appliance circuits. To do this with a range, for example, first turn off the breaker, then have a helper turn on the range. Next, turn on the breaker and see if the range comes on.

CHECKING FOR DAMAGE

1.You an easily diagnose a blown fuse element by looking through the fuse glass. A burned element suggests an overload; a broken element and darkened glass suggests a short circuit.

2. When a plug fuse is blown, the fuse shell may also be damaged. Check it for signs of burning and arcing.

3. A damaged plug fuse will clearly show marks caused by burning and arcing.

4. Burn flashes in a circuit breaker panel are a tell-tale sign of serious damage

CHECKING FOR DAMAGE
CHECKING FOR DAMAGE

 

Design a Kitchen Wiring Plan

A wiring Plan

must accommodate lighting fixtures, outlets for small appliances, and other devices that are often moved from one area to another, and out-lets for large permanent appliances, such as dishwashers, washing machines, and electric ranges.

Creating the Plan

A kitchen probably requires the most complicated plan. For clarity and ease of viewing, we’ve provided two wiring diagrams: one for small-appliance outlets and the other for general lighting outlets. The National Electrical Code defines a general-purpose branch circuit as a circuit that supplies two or more receptacles or outlets for lighting and appliances. An appliance branch circuit is a circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected lighting fixtures that are not a part of an appliance.

As a minimum, Section 210.52(8) of the NEC requires that the dining room, pantry. and kitchen, including countertop receptacles. be supplied by no less than two 20-ampere branch circuits. Remember, the NEC provides the minimum requirements. It is recommended that more than two circuits be provided for these areas. How-ever, these circuits are allowed to also supply the other receptacles in the dining room. pantry, and kitchen. Gas ranges, such as the one shown here, require a is. amp circuit to control clocks, burner ignition devices, and lights. For electric ranges. use a so-amp range receptacle placed on a dedicated circuit.

small appliance circuit
Small appliance circuit

Countertop Receptacles.

Place receptacles so that kitchen appliances supplied with 2-foot power cords, such as toasters, coffee makers, and electric griddles. can reach a receptacle without the use of an extension cord. For example, there must be a receptacle within 2 feet of the end of the counter. There must be a receptacle within 2 feet from each end of the sink. The maximum distance between receptacles is 4 feet. Therefore, if an appliance is placed between the receptacles, the 2-foot cord can reach either receptacle. The spacing around an inside corner is measured on the top of the counter along the wall line.

GFCI Protection.

To protect users of kitchen ap-pliances in the vicinity of water. Section 410(A) (6) requires all kitchen countertop receptacles to be provided with ground-fault circuit-interrupter (GFCI) protection, re-gardless of how far they are located from the sink. Provide GFCI protection by one of two methods. Either install a GFCI receptacle as the first one in the circuit and connect regular receptacles to the load side of the GFCI, which will protect those receptacles downstream, or install a GFCI circuit breaker to protect the entire circuit.

Lighting.

You will notice in the wiring diagram that there are no lighting outlets on the 2o-ampere small appliance branch circuits. Lighting should be provided by 15-ampere circuits. Arrange the lighting circuits in such a manner that should one circuit fail, the space will still be at least partially illuminated by lights on another circuit. Plan on installing three-way switches in such a man-ner that lights can be turned on in the adjoining room before turning off the lights in the room that you are leav-ing. Should table or floor lamps be desired in the kitchen or dining area, install switch-controlled receptacle outlets that are supplied by a 15-ampere circuit.

Calculating  Ampacity

An Overloading Circuit is a real danger in any electrical system and can easily lead to a blown fuse or tripped circuit breaker. Worse. it poses a potential fire hazard and can be a threat to both your life and property. The NEC requires that the demand on a given 4 circuit be kept below its safe capacity (Section 220.14). To calculate the total amperage of the circuit, add up those loads of which you know the amperage. For those loads that are listed in wattage instead of amperage, divide the wattage by the circuit voltage to get the amperage (amps – watts/volts), and add the values to the other am-CSB13 120V-.13 A 60Hz  no5000 min 000 DANGER: Keep hands and body a blade. Contact with blade will result it WARNING: To reduce the risk of understand operator’s manual. Check instantly! Hold saw with both hands.

This product label provides information about the amperage used by the device. peerage loads. Total amperage load for the circuit should not exceed the breaker or fuse rating. The safe capacity of a circuit equals only 8o percent of the maximum amp rating. For a typical 20-amp circuit, the circuit should carry just 16 amps. If you can’t find the amperage or wattage of the appliance, use “Appliance Wattage,”

Height and Clearance Requirements New•construction wiring proceeds from a power or lighting plan. Use these floor plans to lay out what is known as rough-in work. This includes installing the outlet boxes. running the wiring through the rough framing, stripping the wires inside the electrical boxes, and connecting the grounding wires. Because the electrical inspector will re-view the construction site and approve or reject the rough-in wiring, it is necessary to follow NEC requirements when installing wiring and electrical fixtures.

Clearance requirements are especially important to reduce the potential for fire hazards. For example, recessed fixtures not approved for contact with insulation must be spaced at least 1/5 inch from combustible materials NEC Section 4113.116(A)(1). When locating receptacles and switches, adhere to specific height requirements both for reasons of safety and accessibility. Switches, for instance, are not permitted to be any higher than 6 feet 7 inches above the floor or working level (Section 404.8).

Installing Electrical Boxes

Both For Ease Of Use

and aesthetics, receptacle and switch boxes should be kept at a uniform height above the finished floor or work surface. A general rule of thumb is to center receptacle boxes 12 inches above the floor-18 inches for handicapped accessibility. Center receptacle boxes over countertops 4 feet above the finished floor, as well as receptacle boxes in bathrooms and garages. Laundry receptacles are placed at a height of 31/2 feet. Switch boxes, on the other hand, are normally centered 4 feet above the finished floor the maximum for handicapped accessibility. A common type of electrical box used in residential work today is a nonmetallic (plastic or fiberglass) box that may include integral nails for fastening it to stud framing.

Nonmetallic boxes such as this are inexpensive and easy to install. You place the box against a stud, bring the face of the box flush to where the drywall will be after it is installed, and then nail the box in place. Be sure to purchase boxes that have enough depth—at least At to 11/2 inches. This will give you approximately 23 cubic inches of interior box volume in which to tuck your wires. Using cable staples, secure the nonmetallic cable no more than 12 inches from the single-device electrical box. Make sure that at least Vs inch of fully insulated cable will be secured inside of the box after the wires are stripped. Many switch boxes have gauge marks on their sides that allow you to position the box on a framing stud without having to measure depth. Recess boxes no more than’/. inch from the finished wall surface. Mount boxes flush with the surface of combustible materials, such as wood. Another type of electrical box is the handy box: a single switch receptacle box that is often screwed directly to a framing member, using a portable electric drill with a screwdriver bit. They sometimes come with a side mounting flange to aid in installation. One danger, however, is that most handy boxes do not have adequate depth and can, therefore, only accommodate one cable safely. Misuse of this type of box is a code violation and should be avoided. On masonry surfaces, attach boxes using masonry anchors and screws. Simply drill anchor holes in the masonry; then insert the anchors, and mount the box.

Stripping Wires And Cables

There are many different ways to strip electrical cable, but probably the easiest is to use a combination of a cable ripper to peel off the plastic sheathing, followed by a multipurpose tool or wire strippers to remove the insulation on the wires. Most boxes require that about 8 inches of cable wire extend into the box. So strip off 8 inches of sheathing first; then take off about 31$ inch of insulation from the end of each wire. Slide this cable into the box, and attach the outlet device.

Tools  & Material

  •  Multipurpose tool
  • Cable ripper
  • Cable

1.To remove the plastic sheathing from an electrical cable, use a cable ripper. Slide this simple tool over the end of the cable; then squeeze the halves together to pierce the sheathing (top). To cut the sheathing, pull the ripper to the end of the cable (above).

2. Once the sheathing is cut to the end of the cable, pull back the sheathing to where the cable was first pierced (top), and cut off the sheathing using a multipurpose tool or a utility knife at this point (bottom).

3. Use a multipurpose tool to strip the insulation from the ends of the wire. Take off about 5/4 in of insulation, using the appropriate slot on the tool that matches the gauge of the wire.

Stripping Wires And Cables
Stripping Wires And Cables

Preparing for Inspection

Once new framing walls are ready to be wired and electrical boxes have all been put in place, carefully begin pulling the cable through the framing. When you insert a cable end into an electrical box, leave a minimum of 6 inches of extra cable, cutting away the excess. Using a cable staple, secure the cable at a maximum of 12 inches above the single device box.

After you have run all cables through the framing and into the electrical boxes, rip back and remove the sheathing from the cable ends in each box; then strip the individual wires. Before a rough-in inspection can be done, you must also splice together the grounding wires using either green wire connectors or wire crimping ferrules.

Then place the wires securely in their boxes. After a rough-in inspection is performed, install the receptacles and switches. Wait until the drywall is in place be-fore doing this work When the walls are completed and all of the boxes wired, you can install cover plates and turn on the power. Check each receptacle, using a plug-in receptacle analyzer, to verify that all of the wiring has been properly done.

Install the light fixtures then confirm that they are all working. Once you have completed all of this, your work will be ready for final inspection. The inspector will reexamine your work, performing many of the same circuit tests as you.

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