General Information for ElectricalInstallations

OBJECTIVESAfter studying this unit, the student will able to

. explain how electrical wiring information is conveyed to the electrician at the construc-tion or installation site.

. demonstratehow the specificationsare used in estimatingcost and in making electrical in-stallations.

. identifyandexplaintheapplicationof the variouscommonline typesusedon drawings.. explain why symbols and notations are used on electrical drawings.. list the agencies that are responsible for establishing electrical standards and ensuringthat materials meet the standards.

. discuss the metric system of measurement.. begin to refer to the Canadian Electrical Code, Part 1.

THE WORKING DRAWINGS

The architect or engineer uses a set of workingdrawings or plans to make the necessary instruc-tions available to the skilled trades that are to buildthe structure shown in the plans. The sizes, quanti-ties, and locations of the materials required and theconstruction features of the structuralmembers areshown at a glance. These details of constructionmust be studiedand interpretedby each skilledcon-struction trade-masons, carpenters, electricians,and others-before the actual work is started.

The electrician must be able to: (1) convert thetwo-dimensional plans into an actual electricalinstallation, and (2) visualize the many differentviews of the plans and coordinatethem into a three-dimensionalpicture,as shownin Fig. I-Ion page 2.

The abilityto visualizean accuratethree-dimen-sional picture requires a thorough knowledge ofblueprint reading. Since all of the skilled trades usea common set of plans, the electrician must be ableto interpret the lines and symbols that refer to theelectrical installation and also those used by theother constructiontrades.The electricianmust know

the structural makeup of the building and the con-struction materials to be used.

SPECIFICATIONS

Working drawings are usually complex because ofthe amount of information that must be included.

To prevent confusing detail, it is standard practiceto include with each set of plans a set of detailedwritten specifications prepared by the architect.

1

Fig. 1-1 Three-dimensional view of house wiring.

These specificationsprovidegeneralinfonnationto be used by all trades involved in the construc-tion. In addition,specializedinfonnationis givenforthe individual trades. The specifications includeinfonnation on the sizes, type, and desired qualityof the standard parts to be used in the structure.

Typical specifications include a section on"GeneralClauses and Conditions"that is applicableto all trades involved in the construction. This sec-tion is followed by detailed requirements for thevarious trades-excavating, masonry, carpentry,plumbing, heating, electrical, painting, and others.

The plan drawings for the residence used as anexample for this text are included in the back of thetext. The specifications for the electrical work in-dicated on the plans are given in the Appendix.

In the electrical specifications, the list of stan-dard electricalparts and suppliesfrequentlyincludesthe manufacturers' names and the catalogue num-bers of the specifieditems.Suchinfonnationensuresthat these items will be of the correct size, type,and electrical rating, and that the quality will meeta certain standard. To allow for the possibility that

the contractor will not always be able to obtainthe specified item, the phrase "or equivalent" isusually added after the manufacturer's name andcatalogue number.

The specifications are also useful to the elec-trical contractor in that all of the items needed for a

specific job are grouped together and the type orsize of each item is indicated. This informationallows the contractor to prepare an accurate costestimate without having to find all of the data inthe plans.

LINES, SYMBOLS, AND NOTATIONS

The purpose of a drawing is to show the size andshape of an object. Lines, symbols and notationsare used to conveyinfonnation about the drawingtothe viewer.Each of the variousline types used in thedrawing have a specific meaning. The line typeslisted below are named for the function they per-fonn or the portion of the drawing they represent.

Visible lines Visible lines are continuous lineswhich show the visible edges of an object. An ex-ample of a visible line would be the outside edge ofthe foundation wall shown on sheet 5 of the draw-

mgs.

Hidden lines Hidden lines are short dashed lines.

They are used to showthe edgesof an objectthat arehiddenfrom viewby surfaceswhich are closer to theviewer. Hidden lines are used to show the buildingfootings on sheet 2 of the drawings.

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Centre lines Centre lines are used to show the

center of an arc or circle. They consist of alternat-ing long and short dashes. The exact centre of a cir-cle is nonnally indicated by the crossing of the twoshort dashes.

-- --

Section lines A sectional view (also referred to asa section or cross-section) is a view of a building

in which we imagine a portion of the building hasbeen sliced off to reveal the internal constructiondetails. Section lines show the solid parts (walls,floors, etc.) of the portion of the building shown inthe sectional view. Section lines are also referredto as crosshatching. Different types of crosshatch-ing represent different types of materials used inthe building.In SectionA-A on sheet 7 of the draw-ings, different types of crosshatching indicate con-crete used for the basement floor, cement blocksused for the basement walls, and bricks used on theoutside walls above grade.

Cutting plane lines Cutting plane lines consist ofa long dash followedby two short dashes. They areused on drawings to indicate where a building isbeing sectioned.The basementfloor plan, sheet 1 ofthe drawings, uses a cutting plane line to showwhere the buildingis being sectioned.The arrowsateach end of a cutting plane line indicate thedirection you are looking when you are viewingthe section. Refer to section A-A on sheet 7.

A A

L ~~Phantom lines Phantom lines are short dashedlines (about 1-1/2 times as long as the dashes forhidden lines) that are used to show an alternate po-sition. The diagram on page 184 shows two, sin-gle-pole double-throw (SPDT) switches. There aretwo closed switchpositions on a SPDT switch.Thefirst closed position is shown by the solid line andthe second closed position is shown by the phan-tom line.

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Break lines Break lines are used where only a partof the drawing needs to be shown. For example, abreak line might be used in a connection diagramwhere it is necessary to show the termination ofboth ends of a cable but not the cable in between.

~~

Contour lines Contour lines are used on plot plansto show changes in elevation.Dashed contour linesindicateexistinggradesand solidcontour lines showfinished grades.

The architect uses symbols and notations tosimplify the drawing and presentation of informa-tion concerning electrical devices, appliances, andequipment. For example, an electric range outletlooks like this:

~RMost symbols have a standard interpretation

throughout the country,as adoptedby the CanadianStandardsAssociation'sStandnrdZ99.3-1979(R1989).Symbols are describedin detail in Unit 2.

A notation will generally be found on the plans(blueprints)next to a specific symbol calling atten-tion to a variation, type, size, quantity,or other nec-essary information. In reality, a symbol might beconsideredto be a notationbecause,accordingto thedictionary,symbols"representwords,phrases,num-bers, and quantities".

Anothermethodof using notationsto avoidclut-tering up a blueprint is to provide a system of sym-bols that refer to a specific table. For example, thewritten sentences on plans could be included in atable referred to by a notation. Fig. 2-9 (page 18) isan example of how this could be done. The specialsymbols that refer to the table would have beenshown on the actual plan.

CANADIAN ELECTRICAL CODE, PART I(C.E.C., PART I)

Because of the ever-presentshock hazard or dangerof fire through some failureof the electrical system,the electricianand the electricalcontractormust use

approved materials and perform all work in accor-dance with recognized standards. The Canadian

ElectricalCode,PartI is the basic standardthat gov-erns electrical work. Its purpose is to provide infor-mationconsiderednecessaryfor safeguardingpeopleand property against electrical hazards. It states:"Compliancewith the requirementsof this code andproper maintenance will ensure an essentially safeinstallation." Section O-Object, Scope andDefinitions. (Note: All c.E. c., Part I sectionreferences used throughout this text are printedin italics.) It is the electrician's responsibilityto ensure that the installation meets these cri-teria. In addition to the c.E.c., Part I, the elec-trician must also consider local and provincialcodes. The object and scope are discussed inSection 0 of the c.E.c., Part I and should bestudied by the student at this time.

The first edition of the Canadian ElectricalCode was published in 1927. It is revised and up-dated every four years by changing, editing, andadding technical material, sections, articles, tables,and so on, so as to be as up to date as possible rel-ative to electrical installations. For example, theCE.C, Part1 addedSection86 to addressissuesap-plicable to electric vehiclecharging,systems.Thereis also a major revision to Section 18, HazardousLocations, to reflect the European system of iden-tification.

As materials, equipment, and technologieschange, the members of the CEC Committeesolicitcomments and proposals from individuals in theelectrical industry and from others interested inelectrical safety. The committee members meetevery six months to deal with proposals from the42 section subcommittees regarding changes to theCanadian Electrical Code. These are voted on andthe final draft is prepared for publication as theCanadian Electrical Code, Part 1.

The CEC Committeeconsistsof individualsrep-resenting over 50 organizations, including theInternational Association of Electrical Inspectors,the Institute of Electrical and Electronic Engineers,the Canadian Electrical Contractors Association,the National Electrical Code@ (U.S.), theUnderwriters'Laboratoriesof Canada,the CanadianStandardsAssociation,the InternationalBrotherhoodof Electrical Workers,and many others.

Copies of the CanadianElectrical Code,PartImay be ordered from

Canadian Standards Association178 Rexdale BoulevardEtobicoke, ON M9W lR3

Code Definitions

The electrical industry uses many words (terms)that are unique to the electrical trade. These termsneed clear definitions to enable the electrician tounderstandcompletely the meaning intendedby theCode.

Section 0 of the CE. C, Part I includes a "dic-tionary" of these terms. Here are a few of these de-finitions:

Ampacity: means current-carryingcapacity of elec-trical conductors expressed in amperes.

Acceptable: means acceptable to the authorityenforcing this code.

Alive or live: means electrically connected to asource of voltage difference,or electricallychargedso as to have a voltage different from that of theearth. The term may also be used in place of "cur-rent carrying."

Dwelling unit: means one or more rooms for theuse of one or more persons as a housekeeping unitwith cooking, eating, living and sleeping facilities.(Note: The terms "dwelling" and "residence" areused interchangeably throughout this text.)

Identified: (as applied to a conductor) meansa. a white or natural grey covering;b. a raised longitudinal ridge or ridges on the sur-

faceof the extended covering on the conductorsof certain flexible cords.

Voltageof a circuit: means the greatest root-mean-square (effective) voltage between any two con-ductors of the circuit concerned.

Extra-low voltage means any voltage up to andincluding 30 V.

Low voltagemeansanyvoltagefrom 31 to 750 Vinclusive.

High voltage means any voltage above 750 V.

Approved,as appliedto electricalequipment: meansthat such equipment has been submitted for exami-nation and testing to an accredited certification or-ganization and that the equipment conforms to

appropriateCanadian StandardsAssociation(CSA)standards.

Notwithstanding: Rule 8-106(7). In spite of.

Practicable: feasible, possible. Rule 6-408(1)(b).

In the rulesof the CE.C, PartI, the word "shall"indicatesa mandatoryrequirement.Examplesare asfollows:

shall be: compulsory, mandatory, a require-ment, must beshall have: the same as shall beshall not: not allowed,not permittedto be done,must not be, against the code.shall be permitted: is allowed, may be done,not against the code.

A very important rule in the CE.C, Part I isSection 2-024, which statesthat all electricalequip-ment shall be approved and shall be of a type andrating approved for the specific purpose for whichit is to be used. This means that electrical equip-ment must be installed and used in accordancewithCanadian Electrical Code and Canadian StandardsAssociation(CSA) standards.If the equipmentdoesnot have the proper approvalor rating, it may not beinstalled until CSA approval has been obtained.

For example, equipment imported into Canadamust meet with CSA approval before it may be in-stalled. The local hydro inspection authority or theprovincialministryof labourwillprovideinformationon how this may be achieved.

CODE USE OF METRIC (SI)MEASUREMENTS

The CE. C Part I has introduced the use of metricmeasurementsin additionto imperialmeasurements.The metric system is known as the InternationalSystem of Units (SI).

Metric measurements appear in the C.E. c.,Part I as follows:

. In the rules, the metric measurement appearswithits symbol,as shownin Fig. 1-5, the tableof symbolsfor SI units.

. In the tables, the metric prefix accompaniesthe measurement, e.g., kcmil.

. References to trade sizes of conduit will re-flect the traditional inch trade sizes followedby the "Metric Trade Designation" in paren-theses, ego~-in (21-mm) trade size

. Usable space and capacity of boxes are in-dicated in millilitres followed by the cubicinch value in parentheses, or in cubic cen-timetres. One cubic centimetre is equal toone millilitre.

A metric value is not shown for AWG sizes ormotor horsepower ratings.

Guide to MetricUsageIn the metric system, the units increase or decreasein multiplesof 10,100, 1000,andso on.Forinstance,one megawatt (1 000 000 watts) is 1000 timesgreater than one kilowatt (1000 watts).

By assigning a name to a measurement, suchas a watt, the name becomes the unit. Adding a pre-fix to the unit, such as kilo, forms the new namekilowatt, meaning 1000watts. Refer to Fig. 1-2 forprefixes used in the metric system.

megakilohectodekathe unitdecicentimillimicronano

1 000 0001000

100101

0.10.01

0.0010.000 001

0.000 000 001

(one million)(one thousand)(one hundred)(ten)(one)(one-tenth) (1/10)(one-hundredth) (1/100)(one-thousandth) (1/1 000)

(one-millionth) (1/1 000000)(one-billionth) (1/1 000000000)

Fig. 1-2 Metric prefixesand their values.

The prefixesused most commonlyare centi,kilo,and milli. Consider that the basic unit is a metre.Therefore, a centimetreis 0.01 metre, a kilometre is1000metres, and a millimetre is 0.001 metre.

Some common measurements of length andequivalents are shown in Fig. 1-3.

Electricians will find it useful to refer to theconversion factors and their abbreviations shownin Figs. 1-4 and 1-5.

one inch

one foot

one yard

one metre 100= 1 000

1.0933.281

39.370

centimetresmillimetresyardsfeetinches

Fig.I-3 Some common measurements of length andtheir equivalents.

inches (in) x 0.025 4inches (in) x 0.254inches (in) x 2.54centimetres (cm) x 0.393 7inches (in) x 25.4millimetres (mm) x 0.039 37feet (ft) x 0.304 8metres (m) x 3.280 8square inches (in2) x 6.452square centimetres (cm2) x 0.155square feet (ft2) x 0.093square metres (m2) x 10.764square yards (yd2) x 0.836 1square metres (m2) x 1.196metres (m) x 1 000kilometres (km) x 0.621miles (m i) x 1.609

= metres (m)= decimetres (dm)= centimetres (cm)= inches (in)= millimetres (mm)

= inches (in)= metres (m)= feet (ft)

= square centimetres (cm2)= square inches (in2)= square metres (m2)= square feet (ft2)= square metres (m2)= square yards (yd2)= kilometres (km)= miles (mi)

= kilometres (km)

Fig. 1-4 Useful conversions (imperiaI/SI-SIIimperial)and unit abbreviations.

SYMBOLS FOR SI UNITS

Symbol Previously Used UnitSI Unit Multiplying Factor for Conversionto Previously Used Unit

Acm3

°C rise°C temperaturehHzJkgkJkmkPa

IxLmm2m3MHzminmmmm2QPa

vW!IF

ampere(s)cubic centimetre(s)degree(s) (angle)degree(s) Celsiusdegree(s) Celsiushour(s)hertzjoule(s)kilogram(s)kilojoule(s)kilometre(s)kilopascal(s)

luxlitremetre(s)square metre(s)cubic metre(s)megahertzminute(s)millimetre(s)square millimetre(s)ohm(s)pascal(s)

volt(s)watt(s)microfarad(s)

10.06111.81.8 plus 32110.73762.205737.60.6210.2950.3340.1450.0930.2293.28110.76435.315110.039370.0015510.0002950.0003340.000145111

ampere(s)cubic inch(es)degree(s) (angle)degree(s) Fahrenheitdegree(s) Fahrenheithour(s) (time)cycle(s) per secondfoot-pound(s)pound(s)foot-pound(s)mile(s)inch(es) of mercuryfeet of water

pound(s) per square inch (psi)foot-candle(s)gallon(s)feet

square feetcubic feet

megacycles per secondminute(s)inch(es)square inch(es)ohm(s)inch(es) of mercuryfeet of water

pounds per square inch (psi)volt(s)watt(s)microfarad( s)

Fig.I-5 CE.C, Part I Symbols for SI units and conversion factors.

2.54 centimetres25.4 millimetres0.0254 metre

12 inches0.304 8 metre

30.48 centimetres304.8 millimetres

3 feet36 inches

0.9144 metre914.4 millimetres

CANADIAN STANDARDS ASSOCIATION(CSA)

(8The Canadian Standards Association is a nonprofitorganization that was formed in 1919 to developstandards for a variety of organizations and disci-plines.These standardsare the cornerstonefor prod-uct certification,and are subsequently approvedbyprovincial and federal government authorities tobecome recognized throughout the country.

Thousands of manufacturerswork directlywiththe CSA on the certification process and the CSAmark appears on many new products every year.

For more information please write to:

Canadian Standards Association

Customer Service Department178 Rexdale BoulevardEtobicoke, ON M9W 1R3Tel: (416) 747-4000

1-800-463-6727Fax: (416)747-4149http://www.csa.ca

UNDERWRITERS' LABORATORIES OFCANADA (ULC)

Underwriters' Laboratories of Canada is a not-for-

profit organization that maintains and operateslaboratories and the certification service for testingand classification of devices, constructions, mate-rials, and systemsto determine their relation to life,fire, and property hazards.

ULC also publishes standards, specifications,and classifications for products having a bearingon fire, accident, or property hazards.

For more information please write to:

Underwriters' Laboratories of Canada7 Crouse RoadScarborough, ON MlR 3A9Tel: (416) 757-3611

1-800-INFO-ULCFax: (416) 757-9540http://www.u1c.caE-mail: u1cinfo@u1c.ca

STANDARDS COUNCIL OF CANADA(SCC)

The objective of the Standards Council of Canadais to promote efficientand effectivevoluntary stan-dardization as a means of advancing the nationaleconomy, and benefiting the health, safety, andwelfare of the public.

The Council fulfills its mandate by accreditingorganizations engaged in standard development,certification, testing and quality, and environmen-tal registration. It is also responsible for approv-ing National Standards of Canada (NSC).

The Council represents Canada on internationalstandardsbodies or agenciesand accreditsCanadiantechnical experts to international standards com-mittees. The Council also offers a comprehensivefamily of information, products, and services deal-ing with standards, regulations, and conformity as-sessment procedures. Through these activities theCouncil facilitatesCanadian and internationaltrade,protects consumers, and promotes internationalstandards cooperation.

For more information please write to:

Standards Council of Canada1200-45 O'Conner StreetOttawa, ON KIP 6N7Tel: (613) 238-3222http://www.scc.ca

UNDERWRITERS LABORATORIES INC.(UL)

c us

LISTEDUnderwriters Laboratories Inc. (UL), is an inde-pendent not-for-profitproduct-testing,certification,and quality system registration organization thathas evaluated products, materials, and systems inthe interest of public safety for more than a cen-tury. More than 14billion products bearing the ULMark enter the marketplace every year. UL, itsaffiliates, and its subsidiaries are capable of pro-viding manufacturesproduct certificationand man-agement system registration globally through UL'sfacilities in the United States, Canada, Mexico,Europe,the PacificRim, andAsia.The UL Mark forCanada (C-UL) and the Mark of UnderwritersLaboratories of Canada (ULC) mean that productscomply with Canadian requirements. The Canada!U.S. UL Mark signifies that products complywith both Canadian and U.S. requirements. Ifyou have questions about any of UL's Marks, orcompliance or installation of products, call UL'sCodes & Technical Services representatitvein Orangeville, Ont., at 519-942-8962; fax519-942-9307;or e-mail culbob@headwaters.com.

Copies of UL publications may be obtainedfrom:

Underwriters Laboratories Inc.333 Pfingsten RoadNorthbrook, IL 60062Te1:(847) 272-8800http://www.ul.com

ETL Testing Laboratories, Inc. is another na-tionally recognized testing laboratory. They pro-vide a labelling, listing, and follow-up servicefor the safety testing of electrical products to na-tionally recognized safety standards or specifi-cally designated requirements of jurisdictionalauthorities. Information can be obtained by writ-ing to:

Intertek Testing Services3933 US Route 11Cort1and,NY 13045Tel: (607) 758-6439Fax: (607) 756-9891http://www.etl.com

AMERICAN NATIONAL STANDARDSINSTITUTE (ANSI)The American National Standards Institute is an

organization that coordinates the efforts and resultsof the various standards-developing organizations,such as those mentioned in previous paragraphs.Through this process, ANSI approves standardsthat then become recognized as American nationalstandards. One will find much similarity betweenthe technical informationfound in ANSI standards,the Underwriters standards, the InternationalElectronic and Electrical Engineers standards, andthe National Electrical Code@(U.S.).