Power Point Presentation Publisher The GoodheartWillcox Co Inc
Power. Point Presentation Publisher The Goodheart-Willcox Co. , Inc. Tinley Park, Illinois © Goodheart-Willcox Co. , Inc. 1 1 Permission granted to reproduce for educational use only
Chapter 21 Residential Electrical 2 © Goodheart-Willcox Co. , Inc. 2 Permission granted to reproduce for educational use only
Chapter 21 Overview • • Introduction Electrical Terms Service Entrance and Distribution Panel Branch Circuits Circuit Requirement Calculations Outlets and Switches Ground-Fault Circuit Interrupter (GFCI) Low Voltage Exterior Lighting 3 © Goodheart-Willcox Co. , Inc. 3 Permission granted to reproduce for educational use only
Learning Objectives • Define typical residential electrical terms. • Plan for the electrical needs of a modern home. • Identify and explain the three types of electrical circuits used in a residential structure. (continued) 4 © Goodheart-Willcox Co. , Inc. 4 Permission granted to reproduce for educational use only
Learning Objectives • Calculate circuit requirements for a residence. • Explain the advantages and disadvantages of low voltage exterior lighting. 5 © Goodheart-Willcox Co. , Inc. 5 Permission granted to reproduce for educational use only
Introduction • Planning for the electrical needs of a home requires a basic understanding of several factors. – Understanding related terms. – Electrical requirements. – Code restrictions. – Safety considerations. 6 © Goodheart-Willcox Co. , Inc. 6 Permission granted to reproduce for educational use only
Electrical Terms • You must know the following terms to design an electrical plan: – Ampere (amp). – Circuit breaker. – Conductor. – Convenience outlet. – Fuse. – Lighting outlet. 7 © Goodheart-Willcox Co. , Inc. (continued) 7 Permission granted to reproduce for educational use only
Electrical Terms – Ohm. – Receptacle. – Service drop. – Service entrance. – Service panel. – Voltage. – Watt. 8 © Goodheart-Willcox Co. , Inc. 8 Permission granted to reproduce for educational use only
Service Entrance and Panel • The most basic part of a residential electrical system is the service entrance and distribution panel. • The service entrance may be one of two types: circuit breaker or fuse. • Circuit breakers provide overcurrent protection if the load is too high. 9 © Goodheart-Willcox Co. , Inc. 9 Permission granted to reproduce for educational use only
Panel and Breakers (Square D Company) © Goodheart-Willcox Co. , Inc. 10 10 Permission granted to reproduce for educational use only
Service Entrance and Panel • A residence may have 120 or 240 volt service. • Two conductors are required for 120 volt service. • Three conductors are required for 240 volt service. • 240 volt service is recommended. 11 © Goodheart-Willcox Co. , Inc. 11 Permission granted to reproduce for educational use only
Residential Electrical Service • Two voltages are available from a 240 volt, 3 -wire service drop. 12 © Goodheart-Willcox Co. , Inc. 12 Permission granted to reproduce for educational use only
Service Entrance and Panel • Electrical service conductors first terminate at the meter. • Service may be overhead or underground. • In an overhead service drop, the cables must be at least 10' above the ground at all points and 12' above driveways. 13 © Goodheart-Willcox Co. , Inc. 13 Permission granted to reproduce for educational use only
Service Entrance Types • Underground service. 14 © Goodheart-Willcox Co. , Inc. 14 Permission granted to reproduce for educational use only
Service Entrance Types • Overhead service. 15 © Goodheart-Willcox Co. , Inc. 15 Permission granted to reproduce for educational use only
Electrical Conductors • Electrical conductor (cable) is used to bring the current from the service head or underground cable to the meter and then to the distribution panel. • Copper or aluminum electrical cable may be used. 16 © Goodheart-Willcox Co. , Inc. 16 Permission granted to reproduce for educational use only
Conductor Sizes • Conductor diameter increases as the designation number decreases. The smallest circuit conductor permitted by the NEC is Number 14. 17 © Goodheart-Willcox Co. , Inc. 17 Permission granted to reproduce for educational use only
Distribution Panel • Conductors from the meter terminate at the distribution panel. • Electricity is distributed from the distribution panel to various points in the house through branch circuits. • The main disconnect switch is located in the distribution panel. • The NEC recommends a minimum of 100 amp service. 18 © Goodheart-Willcox Co. , Inc. 18 Permission granted to reproduce for educational use only
Typical Distribution Panel (Square D Company) © Goodheart-Willcox Co. , Inc. 19 19 Permission granted to reproduce for educational use only
Circuit Breakers • Circuit breakers are available in a variety of sizes and types. (Square D Company) © Goodheart-Willcox Co. , Inc. 20 20 Permission granted to reproduce for educational use only
Circuit Breakers and Distribution Panel • Common distribution panels designed for circuit breakers include the main breaker, 240 volt circuits, and 120 volt circuits. (Square D Company) © Goodheart-Willcox Co. , Inc. 21 21 Permission granted to reproduce for educational use only
Branch Circuits • A branch circuit is one of several individual circuits from the distribution panel. • The NEC specifies three types of branch circuits for residential structures. – Lighting circuits. – Special appliance circuits. – Individual appliance circuits. 22 © Goodheart-Willcox Co. , Inc. 22 Permission granted to reproduce for educational use only
Lighting Circuits • Used primarily for lighting. • Serve permanently installed lighting fixtures. • Serve receptacle outlets for lamps, radios, and clocks, but not kitchen appliances. (continued) 23 © Goodheart-Willcox Co. , Inc. 23 Permission granted to reproduce for educational use only
Lighting Circuits • Generally use Number 12 copper wire with 20 amp overcurrent protection. This provides 2400 watts of lighting capacity (120 x 20 = 2400). • Three watts of lighting power per square foot of floor space is required, but five or six watts is recommended. 24 © Goodheart-Willcox Co. , Inc. 24 Permission granted to reproduce for educational use only
Special Appliance Circuits • Located in the kitchen, garage, or shop. • Usually above a countertop or workbench. • Designed for electric fry pans, mixers, and blenders, as well as electric drills and power hand saws (tools and appliances that require large amounts of current). (continued) 25 © Goodheart-Willcox Co. , Inc. 25 Permission granted to reproduce for educational use only
Special Appliance Circuits • Generally require Number 12 copper wire with 20 amp overcurrent protection. Each of these circuits is capable of supplying 2400 watts of power. • Lighting outlets should not be operated from these circuits. • The NEC requires at least two special appliance circuits in the kitchen. 26 © Goodheart-Willcox Co. , Inc. 26 Permission granted to reproduce for educational use only
Individual Appliance Circuits • Serve single, permanently installed appliances or equipment. • Each appliance or piece of equipment will have its own circuit (refer to Figure 21 -9 in the textbook). • Special plugs are required for larger users of electricity. (continued) 27 © Goodheart-Willcox Co. , Inc. 27 Permission granted to reproduce for educational use only
Individual Appliance Circuits • The following appliances commonly have individual appliance circuits. – Air conditioner. – Clothes washer. – Countertop oven. – Dishwasher. – Range. • Any 120 volt, permanently connected appliance that is rated over 1400 watts or starts automatically must also have its own circuit. 28 © Goodheart-Willcox Co. , Inc. 28 Permission granted to reproduce for educational use only
Circuit Calculations • Several factors affect the size of the service entrance and number of branch circuits. – Size of the house. – Size and number of appliances. – Lighting to be installed. – Planned future expansions. • Circuit calculations require a series of calculations. (continued) 29 © Goodheart-Willcox Co. , Inc. 29 Permission granted to reproduce for educational use only
Circuit Calculations Example • Size of residence = 1500 square feet. • Lighting circuits: (3 x 1500 = 4500 watts). • Special appliance circuits: 2 for kitchen (120 volts x 20 amp x 2 = 4800 watts). • Individual appliance circuits: 7 circuits (totaling 22, 000 watts). • Total = 31, 300 watts/240 volts = 130. 4 amps. Therefore, this house will require 150 amp service. 30 © Goodheart-Willcox Co. , Inc. 30 Permission granted to reproduce for educational use only
Outlets and Switches • Outlets, switches, and conductor joints must be housed in an electrical box. • Lighting fixtures must be mounted on a box. • Common types of boxes shown. 31 © Goodheart-Willcox Co. , Inc. 31 Permission granted to reproduce for educational use only
Outlets • Various types of convenience outlets are available. • Code requirements affect placement. • Height of convenience outlets is 12" or 18" above the floor, except in the kitchen. • Outlets may be switched for lamps. • Exterior outlets are weatherproof. Use on each side of the structure. 32 © Goodheart-Willcox Co. , Inc. 32 Permission granted to reproduce for educational use only
Types of Outlets (Leviton Manufacturing Co. , Inc. ) © Goodheart-Willcox Co. , Inc. 33 33 Permission granted to reproduce for educational use only
Weatherproof Outlet 34 © Goodheart-Willcox Co. , Inc. 34 Permission granted to reproduce for educational use only
Outlets • Convenience outlets should be located in the attic and crawl space. • “Special outlets” include telephone jacks, TV antenna outlets, home entertainment outlets, burglar alarm systems, and automatic fire alarms. 35 © Goodheart-Willcox Co. , Inc. 35 Permission granted to reproduce for educational use only
Special Residential Outlets (Leviton Manufacturing Co. , Inc. ) © Goodheart-Willcox Co. , Inc. 36 36 Permission granted to reproduce for educational use only
Switches • Switches should be located in a logical place 48" above the floor. • Do not mount behind doors or other inaccessible locations. • Bathroom switches should be out of reach of the tub or shower. • A switch height of 30" to 40" is preferred for wheelchair users. 37 © Goodheart-Willcox Co. , Inc. 37 Permission granted to reproduce for educational use only
Residential Switches 38 (Leviton Manufacturing Co. , Inc. ; Broan-Nu. Tone, A Nortek Company) © Goodheart-Willcox Co. , Inc. 38 Permission granted to reproduce for educational use only
Switches • Most residential switches operate one fixture and are the single-pole switch type. • A three-way switch allows a fixture to be switched from two locations. 39 © Goodheart-Willcox Co. , Inc. 39 Permission granted to reproduce for educational use only
Four-Way Switches • Switching a light from multiple locations is often desirable. • Fixtures may be switched from three locations using two three-way switches and one four-way switch. 40 © Goodheart-Willcox Co. , Inc. 40 Permission granted to reproduce for educational use only
Dimmer Switch • A dimmer switch is a special switch used to adjust the brightness of a light. • A regular electrical box is used to house the switch. (Leviton Manufacturing Co. , Inc. ) © Goodheart-Willcox Co. , Inc. 41 41 Permission granted to reproduce for educational use only
Ground-Fault Circuit Interrupter (GFCI) • A ground-fault circuit interrupter (GFCI) is a safety device that continually monitors the flow of current in a circuit. • A GFCI responds in 1/30 th of a second. • GFCIs can be placed as any receptacle. • The NEC defines when and where GFCIs are used. 42 © Goodheart-Willcox Co. , Inc. 42 Permission granted to reproduce for educational use only
GFCI Protected Outlet 43 © Goodheart-Willcox Co. , Inc. 43 Permission granted to reproduce for educational use only
• Kitchen GFCI Locations – All countertop receptacles within 6' of the sink. • Bathroom – All receptacles. • Garage – All receptacles within reach. • Outdoors – All receptacles within 6'-6" of the grade. • Unfinished basements and crawl spaces – All receptacles except a dedicated outlet. 44 © Goodheart-Willcox Co. , Inc. 44 Permission granted to reproduce for educational use only
Low Voltage Exterior Lighting • Low voltage lighting systems are popular for outdoor use. • Good outdoor lighting is both functional and aesthetic. • A low voltage lighting system consists of lights, wires, one or more controllers, and transformers. • It is more expensive than a 120 volt system. 45 45 © Goodheart-Willcox Co. , Inc. Permission granted to reproduce for educational use only
Planning Low Voltage Exterior Lighting • Decide where you will need light for safety, activities, and security. • Plan for decorative lighting. • Keep basic considerations in mind. – Try to avoid glare. – Locate lights based on their purpose. Outdoor light fixtures are either decorative or designed to be hidden. (continued) 46 © Goodheart-Willcox Co. , Inc. 46 Permission granted to reproduce for educational use only
Planning Low Voltage Exterior Lighting – Use shielded fixtures to hide the light source. – Hide fixtures where they cannot be seen. – Use more, smaller lights. – Remember safety when planning lighting. – Use light to shape an outdoor space. 47 © Goodheart-Willcox Co. , Inc. 47 Permission granted to reproduce for educational use only
Decorative Carriage Lamp 48 © Goodheart-Willcox Co. , Inc. 48 Permission granted to reproduce for educational use only
Walkway Lighting 49 © Goodheart-Willcox Co. , Inc. 49 Permission granted to reproduce for educational use only
Exterior Lighting (Photo courtesy of James Hardie® Siding Products) © Goodheart-Willcox Co. , Inc. 50 50 Permission granted to reproduce for educational use only
Low Voltage Wiring • Low voltage lighting systems are generally easy to install. • Keep several points in mind when installing a system. – Lights farther away from the transformer produce less light due to voltage drop. – Put no more than 100 watts of lighting on one leg of the tee. 51 © Goodheart-Willcox Co. , Inc. (continued) 51 Permission granted to reproduce for educational use only
Low Voltage Wiring – Choose the proper size transformer. – Use a GFCI power source for the transformer. – Consider an indoor switch and timer. – Try to prevent corrosion before it starts. – Call the utility company before digging. – Leave a little extra wire in the layout. – Bury the wires at least 6" deep after checking the setup. 52 © Goodheart-Willcox Co. , Inc. 52 Permission granted to reproduce for educational use only
Low Voltage Wiring • When installing the lighting system, divide the circuit into two legs as shown. This will provide more uniform lighting. 53 © Goodheart-Willcox Co. , Inc. 53 Permission granted to reproduce for educational use only
- Slides: 53