Construction Electrical Terminology. Electricians

Transcription

1 Construction Electrical Terminology Electricians

2 Acknowledgments Winnipeg Technical College and the Department of Labour and Immigration of Manitoba wish to express sincere appreciation to all contributors. Special acknowledgments are extended to the following individuals: Manola Barlow, Independent contractor Doug McKay, Instructor, Winnipeg Technical College Recognition of Prior Learning Coordinator, Winnipeg Technical College Funding for this project has been provided by The Citizenship and Multicultural Division, Manitoba Department of Labour and Immigration. Disclaimer Statements and opinions in this document do not reflect those of Winnipeg Technical College or the project funder, Citizenship and Multicultural Division, Manitoba Department of Labour and Immigration. The information is gathered from a variety of sources and is current and accurate as of the revision date noted. This information is subject to change and will not be further updated. It is the responsibility of the reader to seek current statistics and information. Please contact the Winnipeg Technical College at or if you have questions about the contents of this document 2

3 Table of Contents Introduction Canadian Electrical Code Electrical Code: Crossword Manitoba Hydro Reading Blueprints Circuits Electrical Tools Electrical Tools: Matching Miscellaneous Electrical Terms Electrical Terms: Crossword Answer Key References

4 Introduction As a student studying Electrical Applications, you will hear trade terminology everyday. As a result, it is highly recommended that you become familiar with Electrical terminology, before the start date of your program. This will ease some of the workload required of you during the course. This guide mainly focuses on the some of the basic terms used in residential wiring & the Canadian Electrical Code. it does not include all the key words. Self-tests and answer keys have been included in this guide. If you are scoring below 80% on the selftests, it is recommended that you go back and review those areas. 4

5 Canadian Electrical Code The Electrical Contractor must do all work according to Canadian Electrical Code. (In Manitoba follow, Manitoba Electrical Code 1.) The first section of this booklet will explain what electrical code is, and important terminology relating to electrical code. The Canadian Electrical Code serves as the basis for wiring regulations across Canada. Canadian Electrical Code: The Canadian Electrical Code (CE code) is a standard published by the Canadian Standards Association (CSA) addressing: Electrical safety, shock, and fire hazards of electrical products in Canada. The first edition of the Canadian Electrical Code was published in The current (20th) edition was produced in Code revisions are now scheduled on a three-year cycle, so be sure you are using the current code book! The Code outlines in detail what wiring methods are acceptable and what practices are not allowed. In the current (20th) edition, the Code recognizes that other methods can be used to assure safe installations, but these methods must be acceptable to the authority enforcing the Code in a particular city or Province in Canada. The Code is divided into sections, covering topics such as: Conductors service equipment circuit loading factors Make sure you are familiar with the latest Code requirements before you begin wiring 1 You can find The Manitoba Electrical Code online at: 5

6 grounding and bonding wiring methods protection low-voltage power circuits hazardous (dangerous) locations installation of electrical equipment Additional sections give rules for special areas such as wet locations, patient care areas, emergency systems, temporary installations, and others. The Canadian Electrical Code does not apply to vehicles, systems operated by an electrical or communications utility, railway systems, aircraft or ships. Key Terms Bonding - Connecting wires (conductors). Conductors - A substance that allows an electric current to pass through it easily. Circuit - a circuit is a path between two or more points along which an electrical current can be carried. Circuit loading factors - Criteria that does not allow you to go over the number of receptacles on a circuit, gauge of wire, amperage of the circuit breaker. Electrical equipment - receptacles (outlets), light fixtures, switches, conductors(wires), circuit breakers, electrical panel, conduit, etc. Grounding - The process of connecting equipment to a common ground or earth. This is done as a safety mechanism in order to avoid the unsafe energizing of equipment. 6

7 Low-voltage power circuits - For example, thermostat wires, telephone wire, co-axial cable. Overload - Can be classified as an overcurrent which exceeds the normal full load current of a circuit, Also characteristic of this type of overcurrent is that it does not leave the normal current carrying path of the circuit, that is, it flows from the source, through the conductors, through the load, back through the conductors, to the source again. Protection - against shock and fire hazards. Service equipment - Circuit breakers, fuses. Wiring methods - For example, running power through the switch or receptacle. 7

8 Electrical Code Crossword Directions: Find the words to the clues below. (Study pages 4-5 first, then without looking back, complete the crossword.) Across 5. serves as the basis for wiring regulations across Canada Down 1. process of connecting equipment to earth 2. light fixtures, switches, conductors(wires), etc. 3. allows an electric current to pass through it 4. a path between two or more points along which an electrical current can be carried. 8

9 Manitoba Hydro Manitoba Hydro supplies power to residences and cottages through overhead wires or underground cables. The service supplied is a three-wire service, which is made up of two live conductors and one neutral conductor. With the three-wire service, 120-volt, 120/240 volt and 240-volt capabilities are provided. Key terms Live Conductors - Conductors (wires) that have power running through them. The term hot is often used to describe a wire that has power running through it. Neutral conductor - The neutral conductor is the conductor connected to ground in most existing power systems. However, this is not the definition of the neutral conductor. The definition of the neutral conductor is the conductor that under balanced load conditions will carry no current. In a three-phase system where each of the three phases has an equal load, the current in the neutral conductor will be zero. In practice, it is easiest to ground the neutral conductor. Overhead wires - Wires that are above ground. Underground cables - Wires that are buried under the ground. Reading Blueprints Blueprint - The documents used by contractors and builders that instruct them on how to build. Each set of blue prints should include the following: floor plans; plans for the foundation and information on footings and framing; front, side and rear elevations; a roof plan; electrical layout and Kitchen cabinet layout; and construction details. 9

10 Electrical layouts - Electrical diagrams usually include a legend or key on the page, which explains what each symbol represents. From this diagram the electrician can determine the location of electrical outlets, fans, fixtures, light fixtures etc. Electrical diagrams may also include legends for heating systems, door swings and sizes, furniture placement, and may specify certain finishes. Floor-plan - A floor plan is a simple line drawing showing rooms as if seen from above. Walls, doorways, and windows are often drawn to scale. (Not as detailed as a blueprint.) Symbols used in an electrical floor plan retrieved on March 15,

11 Sample Floor-Plan 3 Circuits What is a circuit? An electrical path between two points. Circuit branch - A point in an electric circuit where current can flow in more than one direction. A circuit branch creates two branches from one main line carrying current. Circuit breakers are now used in new home construction. Fuses were used up to the late 1960 s

12 That means that each circuit branch receives half of the current coming from the main line. In other words, if you had a main line that carried 10 Amps of current, you would have two circuit branches that each had five Amps. Circuit breaker - A device designed to open under an abnormal amount of current flow. The device is not damaged and may be used repeatedly. Rated by voltage, current, and horsepower. De-energized circuit - A circuit that has no power applied to it. Arc-Fault Circuit interrupter (AFCI) - A circuit breaker designed to prevent fires by detecting electrical arcs and disconnect power before the arc starts a fire. Ground Fault Circuit Interrupter (GFCI) - A device that stops the flow of electricity by opening or breaking the circuit when a flow of current to ground is detected. Electrical outlets near water sources like sinks and laundry appliances, as well as all garage and outdoor outlets, should have a ground fault circuit interrupter GFCI). Electrical Panel - An insulated panel on which electrical wires are connected to circuit breakers. Electrical Tools Most electrical wiring jobs are relatively easy to handle with a few inexpensive tools. Circuit tester (Voltage tick) - Simple and inexpensive, a circuit tester plugs into a conventional outlet and will tell you whether the circuit is "hot" (charged) or whether it's properly grounded. Continuity tester - A small, battery-operated continuity tester costs less than $10. It can be used to determine whether wiring is broken and whether electrical circuits are complete. 12

13 Lineman's pliers - A pair of these is the best tool to use for cutting heavy wire or cable and twisting wire ends together. To twist two wires together, hold them side by side with one hand, their stripped ends aligned, and point the blunt end of the pliers in line with them, clamp down, and twist in a clockwise direction. Long-nose pliers - Long-nose pliers are great for bending small loops at wire ends or for cutting off wires (most include a wire-cutting section). Use the pointed end of the pliers to form a smooth, 3/4-circle at a wire's end, designed to circle around a screw terminal (always hook the wire onto the terminal with the end of the bend sweeping clockwise from the wire). Multi-meter - You'll want to have a multi-meter on hand for making a variety of continuity checks, checking voltage, and other similar tasks. Read the manufacturer's instructions for a thorough understanding of techniques. Multi-meters, which do the job of ohm meters, volt meters, and related tools, are sold at consumer electronics stores. Neon voltage tester - This helpful little tool can tell you whether wires are "hot" or not. When using it, be sure to hold only the insulated probes- - not the bare parts. Touch one probe to what you suspect is a hot wire and the other probe to a neutral wire or grounding wire (or grounded metal electrical box). If the small light glows, the circuit is live. Screwdrivers - You'll want an assortment of screwdrivers with insulated rubber grips. Be sure to get both flat-bladed and Phillips-head drivers. 13

14 Wire stripper - Most electrical wires run inside a sleeve of insulation, a plastic, rubber or paper coating that prevents bare conductors from shorting against each other or shocking you. When splicing wires(connecting two or more wires together) or connecting them to devices, you must remove the insulation, a relatively simple job when you have the right tool-- an inexpensive wire stripper. The stripper should be set so that it cuts the insulation but doesn't nick the wire (or use the slot that matches the wire conductor's size). Hold the wire with one hand, bite into the insulation with the stripper, about 1/2 inch to 3/4 inch from the wire's end, rock the stripper back and forth, and pull the insulation off the end of the wire. 14

15 Matching: Electrical Tools Directions: Write the correct name next to the tool on the right. (Answers on pg. 19)

16 Miscellaneous electrical terms Ampere - The measurement of intensity of rate of flow of electrons in an electrical circuit. An ampere is the amount of current that will flow through a resistance of one ohm under pressure of one volt. Electrical Load - That part of the electrical system which actually uses the energy or does the work required. Ohm - The unit of measure for electric resistance. An ohm is the amount of resistance that will allow one ampere to flow under a pressure of one volt.. Ohm's Law: The relationship between voltage, current and resistance, expressed by the equation V=IR, where V is the voltage in volts, I is the current in amperes, and R is the resistance in ohms. Over current - A condition which exists on an electrical circuit when the normal load current is exceeded. Over currents take on two separate characteristics - overloads and short circuits. Overload - Can be classified as an overcurrent which exceeds the normal full load current of a circuit, Also characteristic of this type of overcurrent is that it does not leave the normal current carrying path of the circuit. Recessed lighting - Also known as pot lights. Receptacle - Also known as an electrical outlet. Retro-fit - Servicing old technology. Resistive Load - An electrical load which is characteristic of not having any significant inrush current. When a resistive load is energized, the current rises instantly to its steady-state value, without first rising to a higher value. 16

17 Semiconductor Fuses - Fuses used to protect solid-state devices. (see High Speed Fuses). Short Circuit - Can be classified as an overcurrent which exceeds the normal full load current of a circuit by a factor of many times (tens, hundreds or thousands greater). Also characteristics of this type of overcurrent are that it leaves the normal current carrying path of the circuit, (it takes a "shortcut" around the load and back to the source). Short Circuit Rating - The maximum short circuit current an electrical component can sustain without the occurrence of excessive damage when protected with an overcurrent protective device. Volt - The volt (symbolized V) is the Standard International (SI) unit of electric potential or electromotive force. Voltage Rating - The maximum open circuit voltage in which a fuse can be used, yet safely interrupt an overcurrent, exceeding the voltage rating of a fuse impairs its ability to clear an overload or short circuit safely. 17

18 Electrical Terms: Crossword Across 4. The unit of measure for electric resistance. 5. Recessed lighting. 7. The measurement of intensity of rate of flow of electrons in an electrical circuit. 8. Standard International unit of electric potential or electromotive force. 11. diagrams can determine the location of electrical outlets, fans. Down 1. not having any significant inrush current 2. Also known as an electrical outlet. 3. exceeds the normal full load current of a circuit 4. V=IR 6. Servicing old technology. 9. simple line drawing showing rooms as if seen from above. 10. documents used by contractors and builders that instruct them on how to build. 18

19 Answer Key Crossword (Page 8) 1. grounding 2. electrical equipment 3. conductors 4. circuit 5. Canadian Electrical Code Matching (Page 15) 1. Circuit tester (Voltage tick) 2. Lineman s pliers 3. Wire stripper 4. Neon voltage tester 5. Continuity tester 6. multi-meter 7. Long-nose pliers Electrical Terms: Crossword (Page 18) Across 4. ohm 5. potlights 7. ampere 8. volt 11. electrical Down 1. resistive load 2. receptacle 3. overload 4. ohmslaw 6. Servicing old technology. 9. floor plan 10. blueprint 19

20 References Manitoba Hydro, Retrieved on April 20, 2008, from: Glossary of Terms, Retrieved on April 26, 2008, from: How to Read Blueprints, Retrieved on April 26, 2008, from: Updated: August