Unit 2: Drawings and Specifications

List the 3 types of drawings

architectural

schematic

wiring

Architectural drawings show

floor plans

relative positions

distances between elements

Schematic drawings show

significant components and their relationships

What is used to represent devices in a schematic drawing

standard icons

Wiring drawings description

similar to schematic

pictures may look like what they represent

layout of pictures may resemble layout of devices

Technical drawings show

size and shape of an object

Basic elements of technical drawings

lines

symbols

dimensions

notations

Visible lines

continuous

show visible edges of an object

Which lines on a diagram show visible edges of an object

visible lines do

Hidden lines: description

short, dashed lines

Hidden lines show

edges of object hidden from view by surfaces closer to the viewer

Which lines show edges of hidden objects

Hidden lines do

Centre lines description

alternating long and short dashes

Centre lines show

centre of an arc or circle

Section lines: description

aka crosshatching

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Section lines show

portion of a building that has been sliced to reveal internal construction details

Lines that reveal construction details and/or solid parts of a building are the

the section lines

Cutting plane lines: description

long dash followed by two short dashes

Cutting plane lines do what

indicate where the building is being sectionedW

The lines that indicate where the building is sectioned are the

The cutting plane lines

The arrows at the end of cutting plane lines tell us

the direction you are looking

Phantom lines: description

short, dashed lines (approx. 1.5x the size of hidden lines)

How can you tell the difference between phantom lines and hidden lines

the phantom lines are about 1.5x bigger than hidden lines

Phantom lines show

an alternative position

Which lines show an alternative position of an object

the phantom lines

Where are break lines used

where only a part of the drawing needs to be shown

Which lines are used when only a part of a diagram needs to be shown

the break lines

Describe contour lines

Wavy or curved lines

Which lines indicate elevation on a print

contour lines

Line weight

thickness of a line used on a drawing

Object lines have a heavier or lighter line weight than other lines

heavier line weight

Pictorial drawings

3D drawings that show 2 or more surfaces in one view

What is the problem with pictorial drawings

they distort shapes and are hard to dimension

Orthographic drawings

show true size and shape of an object using a number of views

Orthographic drawings: top view is called

plan

Orthographic drawings: side view is called

elevation

Plan view shows

how a building will look when viewed directly from above

Plan views are used to show

lengths and widths

Elevation

side view of the building

Elevation shows

heights and widths

Elevation drawings used to visualize

outside walls, interior walls, placement of things (cupboards, equipment, etc)

Graphic symbols used to represent

equipment and componentsS

Symbols are used to show

size, location and rating of equipment

Which organization approves national standards for symbols on construction drawings

SCC

Symbols with dashed lines indicate

future equipment

T/F: orientation of equipment changes the meaning of the symbol

False

Do electrical plans show approximate or exact location of equipment

they show approximate location only

Used to show size of an object

dimensions

Metric dimensions units

millimeters (mm)

meters (m)

American dimensions

feet (ft)

inches (in)

fraction of an inch

What are the two most common uses for single outlet receptacles

Sump pumps

kitchen clock outlets

Full scale drawing

drawing is the same size as the object

Reduced scale

drawing is proportionally smaller than actual size

Enlarged scale

Drawing is proportionally larger than the object it represents

3 types of scales

architectural

engineering

metric

Purpose of working drawings

to provide instructions to the skilled trades that are involved in building the structure

Information provided by the working drawings

sizes, quantity, locations and construction features of materials needed

Do electricians need to know the symbols and lines that apply to the other trades

yes, absolutely

Set of drawings includes

site plan

floor plans

elevations

details and sections

legend and symbols

schedules

diagrams

shop drawings

Which drawing shows lot dimensions

the site plan

Site plan includes

north-pointing arrow

utility locations and connection points

outdoor lighting

easements

contour lines

accessory buildings

trees to be saved

Which drawing shows room measurements, wall thickness, door sizes, windows, door swings

the floor plans

The elevation drawings show

interior and exterior vertical faces

Drawings: details

large-scale drawings used when floor plans and elevations can’t provide enough details

Legend of symbols

provides contractors/electricians with information to interpret the drawings

Schedules

list of equipment and/or finishes

Diagrams

quickly show flow of power

One-line diagrams

power, phone, fire alarm systems

Riser diagrams

vertical details

Shop drawings

show details of custom-made equipment for a specific job

Purpose of specifications

to reduce confusion by providing written descriptions of materials and methods of construction

Specifications include

sizes, type, desired quality of parts to be used