Wiring is subject to safety standards for design and installation. Allowable wire and cable types and sizes are specified according to the circuit operating voltage and electric current capability, with further restrictions on the environmental conditions, such as ambient temperature range, moisture levels, and exposure to sunlight and chemicals.
Wiring safety codes vary by locality, country or region. The International Electrotechnical Commission IEC is attempting to harmonise wiring standards amongst member countries, but significant variations in design and installation requirements still exist.
LearnEngineering team try to Helping the students and others who cannot afford buying books is our aim. Wear latex gloves to a quarter turn to help spread the cement.
Allow the joint to set protect your hands. The cement should be applied past the undisturbed for 10 minutes.
Boxes for wall with masonry anchors, or use Attach an offset fitting to each knockout receptacles in an unfinished basement masonry anchors and panhead screws. Laundry receptacles usually are mounted at 48". Remove any with pipe straps and masonry anchors. Continue attaching or a round file.
Attach the conduit to 3 ft. You can also use a the offset fitting on the box, and tighten 10 ft. The cover on power. Open a knockout in the panel, breaker panel outward. Remove the elbow fitting can be removed to attach a setscrew fitting, and install the the cover on an elbow fitting when make it easier to extend a fish tape and last length of conduit. Note: Use extreme panel and 3" extending beyond the front tip of the fish tape.
The systems include the boxes that house the switches and receptacles tend to be very shallow and more difficult to work with than ordinary boxes.
The new circuit with surface-mounted wiring components main advantage to a surface-mounted wiring system is at least starting at the point where the branch circuit that you can add a new fixture onto a circuit without wire reaches the room from the service panel.
But cutting into your walls. They are not allowed for some connected to the hot wire in the switch box before it specific applications damp areas such as bathrooms, is connected to the switch otherwise, the surface- for example in many areas, so check with the local mounted wiring circuit will be off whenever the building authorities before beginning a project.
And switch is off. After Before Surface-mounted wiring circuits are networks of cable channels and electrical boxes that allow you to run new wiring without cutting into walls.
If you have a room with too much demand on a single receptacle inset , installing a surface-mounted circuit with one or more new outlets is a good solution. The tracks house Original receptacle box inside wall THNN wires that run from the new box to new receptacles and light switches. A Lighter-duty plastic raceways A , used frequently in office buildings, are made of snap-together plastic components. For home wiring, look for a heavier E metal-component system B. Both systems D include box extenders for tying in to a receptacle C , elbows, T-connectors, and C couplings D , and boxes for fixtures E.
Remove the cover plate a new receptacle or light see pages to Measure from from the receptacle by unscrewing the screw that holds the the power source to the new receptacle or switch. Purchase plate to the electrical box. Set the screws and the plate aside. Buy a surface-mounted starter box, new receptacle box, and the electrical box it is attached to. If your existing and fittings for your project the raceway product packaging receptacle is not a tamper-resistant model replace it with one usually provides guidance for shopping.
Hold two long screws that hold it to the box. Depending side of the receptacle. If the sensor wires and a bare wire. Detach these wires and set the does not beep or light up, the receptacle is dead and you can receptacle aside. Pull all the wires you just disconnected opening for the track using pliers. Often the prepunched through the opening. Screw the mounting plate to the knockouts have two profile options—make sure the knockout existing receptacle box with the included mounting screws.
Secure the track or conduit in a vise or clamping work support, and cut with a hacksaw. Once the cut is made, file the metal burrs smooth with a metal file. At the new receptacle location, transfer the height of the top of the starter box and mark a reference line. If possible, locate the box so at least one screw hole in the mounting plate falls over a wall stud. Position the mounting plate for the receptacle box up against the reference line and secure it with screws driven through the mounting plate holes.
If the plate is not located over a wall stud, use wall anchors see below right. Mark screw locations on the wall, and then drill a narrow guide hole for the screw anchor. Drive the anchor into the guide holes until the flange is flush with the wall surface.
Ideally anything you attach to a drywall wall should be anchored at a wall stud location. Of course, in the real world this often is not possible. Some work better than others. For this, use coarse-threaded, screw-in anchors. Use a stud finder to locate and mark all of the wall framing members between the old receptacle and the new one. Attach mounting clips for the track at the starter box and the new receptacle box. The clips should these marks. Install the mounting plates directly below the pieces the box.
Snap the raceway into the clip below the knockout. Repeat this same procedure at the new receptacle box. Snap the long piece of track into the Measure the distance between the ends of the horizontal parts of the elbows, and cut mounting clips. Line up one end of the a length of raceway to that length. Be sure to measure all the way to the base of the track with the end of an elbow and tap clip, not just to the tips of the connector points. At the new receptacle location, snake the ends of the wires up through the vertical piece of track and into the new receptacle box.
There should be about 3" of wire coming out at each box. Use corner pieces to guide around corners. Corners are available for inside or outside corners and consist of a mounting plate and a cap piece.
You can use straight connector pieces to join two lengths of track. Much like an elbow piece, they have a mounting plate and a cover that snaps over the wiring. Cut black, white, and green THNN wire about 2 ft. Snake the end of each wire into the starter box, through the knockout, and into the vertical track. Then snake the wire all the way through the long piece of track so about 12 to 16" comes out on each end.
Begin at the new pieces into place over the mounting plates, one at the starter receptacle location. Wrap the end of the black wire around the box and another at the new receptacle location. You may need bottom gold screw on the side of the receptacle. Make sure all of the wire fits completely within the cover pieces. Connect the green wire to the green-colored screw on bottom of the receptacle align with the holes in the box.
Use a the bottom of the receptacle. Attach the cover plate. First make sure the power is still off with your touchless opposite the gold one you just used. Tighten the screw. Wrap the end of the black wire around the top gold screw on the side of the receptacle. Take the Wrap the end of the old white wire around the silver black wire that goes into the raceway and wrap the end of screw opposite the copper one you just used.
Tighten the wire around the bottom gold screw on the side of the the screw. Join one end receptacle into the box so the holes in the top and bottom of the pigtail with the ends of the bare and green wires in the of the receptacle align with the holes in the box.
Use a box using a wire connector. Wrap the other end of the pigtail screwdriver to drive the two long mounting screws that hold around the green screw on the receptacle. Install the cover plate. You can now restore the power and test your new receptacle. The box may be as simple as a small handy box for making a splice or as complex as a amp main service panel.
It is typically rectangular, square, round, or octagonal, but be aware that the boxes are shaped as they are for specific reasons, so make sure you are using the right one for the job. Installing a box that is too small is an extremely common wiring mistake that is easy to understand: small boxes cost less.
But they are not one-size fits all. The smallest common boxes, called handy boxes, may be used only for a single device such as a switch or receptacle with no more than three conductors. Be sure to refer to a box fill chart see page 60 to learn which size and shape box is required for your job.
Electrical panels function like other electrical boxes insofar as they house connections, but they also house breakers or fuses and other parts that transmit power from the service entry to the individual circuits. Subpanels are smaller electrical panels that perform the same function but are supplied by the main service panel so they can distribute power into multiple circuits in a remote spot.
Replace an undersized box with a larger box using the Electrical Box Fill Chart right as a guide. Do not overfill the box inset. They are ceiling joists. The metal braces extend Single-size rectangular boxes shown used for cable splices and ganged to fit any joist spacing and are nailed or above may have detachable sides that receptacles or switches.
To install one screwed to framing members. Foam gasket Outdoor boxes have sealed seams Old work boxes can be installed to Plastic boxes are common in new and foam gaskets to guard a switch upgrade older boxes or to allow you construction.
The box may include or receptacle against moisture. One type above has built-in framing members. Wall switches must metal parts. Code compliant models clamps that tighten against the inside of have grounding screws if installed in include a watertight hood that protects a wall and hold the box in place.
Common styles include single-gang A , double-gang B , and triple-gang C. Double-gang and triple-gang boxes require internal cable clamps. Metal boxes should be used for exposed indoor wiring, such as conduit installations in an unfinished basement. Metal boxes also can be used for wiring that will be covered by finished walls.
Plastic retrofit boxes are used when a new switch or receptacle must fit inside a finished wall. Use internal cable clamps. B C A D F E Additional electrical boxes include, cast aluminum box A for use with outdoor fixtures, including receptacles that are wired through metal conduit these must have in-use covers if they house receptacles ; old work ceiling box B used for light fixtures; light-duty ceiling fan box C with brace that spans ceiling joists; heavy-duty retrofit ceiling fan box D designed for retrofit; PVC box E for use with PVC conduit in indoor or outdoor setting; vapor-proof ceiling box with foam gasket F.
A variety of adapter plates are available, have internal cable clamps. After installing cables in the including junction box cover plate A , single-gang B , box, tighten the cable clamps over the cables so they are double-gang C , and light fixture D.
Adapter plates gripped firmly, but not so tightly that the cable sheathing come in several thicknesses to match different wall is crushed. Grounding screw Pigtail A B C Metal boxes must be bonded to the circuit grounding Cables entering a metal box must be clamped. A system. Connect the circuit grounding wires to the box variety of clamps are available, including plastic clamps with a green insulated pigtail wire and wire connector as A, C and threaded metal clamps B.
Most are sold prefitted with installation hardware—from metal wings to 10d common nails attached at the perfect angle for a nail-in box. The bulk of the nonmetallic boxes sold today are inexpensive blue PVC. You can also purchase heavier-duty fiberglass or thermoset plastic models that provide a nonmetallic option for installing heavier fixtures such as ceiling fans and chandeliers. In addition to cost and availability, nonmetallic boxes hold a big advantage over metal boxes in that their resistance to conducting electricity will prevent a sparking short circuit if a hot wire contacts the box.
Nonmetallic boxes generally are not approved Low cost is the primary reason that blue PVC nail-in for exposed areas, where they may be susceptible boxes are so popular.
Not only are they inexpensive, they also feature built-in cable clamps so you may not need to buy to damage.
Their lack of rigidity also allows them to extra hardware to install them. The standard PVC nail-in box compress or distort, which can reduce the interior is prefitted with a pair of 10d common nails for attaching to capacity beyond code minimums or make outlets exposed wall studs.
These boxes, often called handy boxes, are difficult to attach. B A C Nonmetallic boxes for home use include: Single-gang, double-gang, triple gang, and quad boxes A ; thermoset and fiberglass boxes for heavier duty B ; and round fixture boxes C for ceiling installation nail-in and with integral metal bracket. These Nail-in boxes A are prefitted with 10d are not knockouts as you would find in metal boxes.
In single-gang boxes right , nails that are attached perpendicular to the pressure from the tab is sufficient to secure the cable as long as it enters with the face of single-gang boxes and at an sheathing intact and is stapled no more than 8" from the box. On larger boxes left , inward angle for better gripping power you will find traditional knockouts intended to be used with plastic cable clamps that on larger boxes.
Side-mount boxes B resemble metal cable clamps. Use these for heavier gauge cable and cable with more feature a nailing plate that is attached than three wires. Ribs Distortion can occur in nonmetallic boxes when nails Integral ribs cast into many nonmetallic boxes are used or other fasteners are overdriven or installed at improper to register the box against the wall studs so the front edges angles, or when the semiflexible boxes are compressed into of the box will be flush with the wall surface after drywall improperly sized or shaped openings.
This can reduce the box is installed. Otherwise, use a piece of the wallcovering material as a reference. Use your wiring plan as a guide, and follow electrical code height and spacing guidelines when laying out box positions.
Always use the deepest electrical boxes that are practical for your installation. Using deep boxes ensures that you will meet code regulations regarding box volume and makes it easier to make the wire connections. Some electrical fixtures, such as recessed light fixtures, electric heaters, and exhaust fans, have built-in wire connection boxes.
Install the frames for these fixtures at the same time you are installing the other electrical boxes. The box heights recommended on the following pages are for most situations. Boxes heights for handicap accessible situations are different. Electrical boxes in adjacent rooms should be positioned close together when they share a common wall and are controlled by the same circuit. This simplifies the cable installations and also reduces the amount of cable needed.
Common recessed fixtures include electric blower-heaters left , bathroom vent fans right , and recessed light fixtures.
Install the frames for these fixtures at the same time you are installing the other electrical boxes along the circuit. Surface-mounted fixtures such as electric baseboard heaters pages to and under-cabinet fluorescent lights pages to also have built-in wire connection boxes. These fixtures are not installed until it is time to make the final hookups. Standard Position each box against a stud so the front face will be receptacle boxes should be centered 12" above floor level.
Anchor the box by driving the mounting nails into the stud. Use adapter plates that and screwdriver. Always introduce the rotating a screwdriver in the knockout. Nail the ends of the brace bar to joists so the face of the box for a mirror or medicine cabinet. Place will be flush with the finished ceiling surface.
Slide the box along the brace bar to the the box for a ceiling light fixture in the desired position, and then tighten the mounting screws. Use internal cable clamps center of the room. Position each box when using a box with a brace bar.
The box for a thermostat is mounted at 48" to 60". Position the box on the cross block so the front face will be Position each box against the side of a stud so the front face flush with the finished wall, and drive the mounting nails into will be flush with the finished wall, and drive the mounting nails the cross block. In the kitchen shown here, boxes above the countertop are 45" above the floor, in the center of 18" backsplashes that extend from the countertop to the cabinets.
All boxes for wall switches also are installed at this height. The center of the box for the microwave receptacle is 72" off the floor. The centers of the boxes for the range and food disposer receptacles are 12" off the floor, but the center of the box for the dishwasher receptacle is 6" off the floor.
Code requires that the front face of boxes be flush with the finished wall surface, so how you install boxes will vary depending on the type of wall finish that will be used. The easiest way will support heavy chandeliers and ceiling fans. A remodeling to install one is by nailing the brace to open ceiling joists brace such as the one seen here is designed to install through from above. If the ceiling is insulated, pull the insulation away a small cutout in the ceiling inset photo.
Open one knockout for each cable that will enter the box Test for power. Carefully remove any tape or wire connectors using a hammer and screwdriver. Any unopened knockouts from the exposed slice. Disconnect the illegally spliced wires. Tighten the clamp with a box, and screw a locknut onto each or nails. See if there is any slack in cable clamp. Locknut 6 7 Grounding screw 8 Lugs Cover plate Tighten the locknuts by pushing Use wire connectors to reconnect Carefully tuck the wires into the box, against the lugs with the blade of the wires.
Pigtail the copper grounding and attach the cover plate. Turn on the a screwdriver. Make sure the box remains accessible and is not concealed by finished walls or ceilings. You also may find that an older switch or receptacle box is too shallow to accommodate a new dimmer or GFCI safely. A pop-in box typically has wings, tabs, or brackets that are drawn tight against the wall surface on the wall cavity side, holding the box in place.
It can be made either of metal or plastic. For walls, they include plastic retrofit boxes with flip-out wings A , metal or plastic boxes with compression tabs or Screwdriver Wallboard saw brackets B , metal retrofit boxes with flip-out wings C , and Pencil Template if provided metal boxes with bendable brackets, also known as F-straps, String Plastic or metal pop-in box D. For ceilings, plastic fixture boxes with flip-out wings E Electrical tape Eye protection are available.
Shut off power and they fall into the wall cavity when the old box is removed. Identify the location Disconnect the cable clamps and slide the old box out. Install a of nails holding the box to the framing member and cut the new pop-in box see next page. If no of a wallboard saw or by drilling a small the box no cable clamp is required with template is provided, press the pop-in hole inside the lines, and make the a plastic box; just be sure not to break box against the wall surface and trace cutout for the box.
Variation: Feed cable into the new Tighten the screws that cause the flip-out wings to pivot right until the box is held box and secure it in the opening after firmly in place. Connect the switch or receptacle that the box will house. With this pop-in box, bracket arms are inserted at the sides of the box top and then bent around the front edges to secure the box in the opening bottom. The main panel may be found in the basement, garage, amp Service Panel utility area, or on an exterior wall and can be identified by its metal casing.
Before making any repair to your electrical system, you must shut off power to the correct circuit at the main panel or at the subpanel where the circuit begins. Every circuit in every panel should be labeled see page 22 so circuits can be identified easily.
Panels vary in appearance, depending on the age of the system. Very old wiring may operate on amp service that has only two circuits. New homes can have up to amp service with 30 or more circuits. Find the size of the service by reading the amperage rating printed on the main fuse block or main circuit breakers. Regardless of age, all panels have fuses or circuit breakers see pages 78 to 81 that protect each circuit from overloads.
In general, older service panels use fuses, while newer panels use circuit breakers. In addition to the main panel, your electrical system may have one or more subpanels that protect some of the circuits in the home. A subpanel has its own circuit breakers or fuses. The subpanel resembles the main service panel but is usually smaller. It may be located near the main panel, or it may be found near the areas served by the new circuits.
In these areas, all house wiring is done with electrical metallic tubing thinwall. There are also instances where a governing body has legislated action that waives specific NEC requirements, feeling that the NEC was too restrictive on that particular issue. Such instances are very rare. The instructor is encouraged to furnish students with any local variations from the NEC that would affect this residential installation in a specific locality.
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Cross wiring 3. Conduit wiring 4. Batten wiring 5. Channel wiring 6. PVC 4 core flexible round cable 4 x 70 x 0. PVC 3 single strand double insulated cable 5. PVC single core single strand cable 18 SWG "PVC Polyvinyl chloride, more correctly but unusually poly vinyl chloride , Commonly abbreviated PVC is the third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene. The rigid form of PVC is used in construction for pipe and in profile applications such as doors and windows.
It is also used for bottles, other non-food packaging, and cards such as bank or membership cards. It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is also used in plumbing, electrical cable insulation, imitation leather, signage, inflatable products, and many applications where it replaces rubber. Pure poly vinyl chloride is a white, brittle solid. It is insoluble in alcohol but slightly soluble in tetrahydrofuran.
Electrical tape or insulating tape is a type of pressure-sensitive tape used to insulate electrical wires and other materials that conduct electricity. It can be made of many plastics, but vinyl is most popular, as it stretches well and gives an effective and long lasting insulation. Almost all the electrical and electronics systems contain at least one switch, which is used to make the device ON or OFF.
In addition, a switch is used to control the circuit operation and user may able to activate or deactivate the whole or certain parts of the connected circuit. Generally, Switches can be categories as. There are many types of Mechanical switches and they are also being categories on the basis of power handling capacity. The contact material is chosen by keeping in mind that the metal oxides, which produced due to corrosion, are mostly insulator and layers of such oxides on the switch plates will hinder the normal operation of the switch.
When a user press the button of the switch, then the plates of the switch connect with each other and the current starts to flow and vice versa. We can send two different signals to same pin by using this switch.
Because of this functionality, this switch is also called selector switch. This switch is mostly used, where we have to break both ground and lines at the same time.
This switch has two common pins and four signal pins. Total four different combinations of singles can be applied to the input pins of this switch. What is Intermediate switch, its construction and how it works? There are four terminals in intermediate switch by which it changes the flowing of current from one circuit to another circuit fig1. The four terminals of intermediate switch is shown in fig 1 label as A, B, C, D.
In some cases, the terminal contacts of switch is meet terminal A with terminal C and terminal B meet with terminal D as shown in fig 1 a. When the knob of the switch is UP, then the vertical contacts are meeting i.
AC and BD as shown in fig 1a. AB and CD as shown in fig 1b. In Fig 2, a lamp is controlled from three different places by using two, 2-way switches and one intermediate switch. A lamp is controlled from six different places by using two, 2-way and four intermediate switches. Key Point: You can control a lamp from many different places by adding more intermediate switches. Electrical and Electronic Switches: The Above discussed switches are Mechanical switches and they are user manually operated.
Now, we are going to discuss Electrical switches, which are faster in response than mechanical switches and can be switched automatically by an electronic circuit like microcontroller or microprocessor.
They can also be categories on the basis of current and voltage rating like mechanical switches. Transistor:- Transistor can be used in different mode of operation but we are going to discuss the transistor as a switch. If we apply a large amount of current at the base of the transistor keeping in mind the maximum allowed current for the this type of transistor then we can run this transistor in deep saturation mode 2.
Mosfets:- Mosfet can also be used for switching purpose at high frequencies. They can operate at Mega hertz frequencies. Mostly, Mosfets used for PWM pulse width modulation. Mosfets have three terminals. Relays:- A Relay is an electromechanical device, which consists of an electromagnet. When a current is flowing through the coil, it becomes an electromagnet and this electromagnet can be used for switching purposes.
Their contacts can fall into any category, e. When they do work moving charges against the electric force, some of this work is already converted to thermal energy in the battery. The amount of energy lost to thermal energy in the battery is Ir, where I is the current flowing in the circuit and r is the internal resistance of the battery.
The voltage across the battery terminals therefore drops from the nominal value V to V - Ir when a current is flowing in the circuit. In a circuit diagram we represent the internal resistance of the battery by a resistor r connected in series with the emf.
A voltmeter is a device used to measure voltages, while an ammeter measures currents. Meters are either analog or digital devices. Analog meters show the output on a scale with a needle, while digital devices produce a digital readout.
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