Drawings

Question 1

Projection

Answer 1

A representation of an object on a 2D plane

Question 2

Orthagonal Projection

Answer 2

Shows the ‘faces’ of an object: front, back, left, right, top, bottom.

Question 3

Isometric Projection

Answer 3

Represents the object three dimensionally from a given corner.

Question 4

First Angle

Answer 4

A projection of an object onto a plane that sits behind the object

Question 5

Third Angle

Answer 5

A projection of an object onto a plane between the object and the viewer

Question 6

Leader Line

Answer 6

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Question 7

Outline

Answer 7

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Question 8

Hidden Outline

Answer 8

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Question 9

Extension Line

Answer 9

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Question 10

Dimension Line

Answer 10

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Question 11

Centre Line

Answer 11

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Question 12

Perspective Drawing

Answer 12

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Question 13

Oblique Drawing

Answer 13

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Question 14

Length

Answer 14

The longer side of an object

Question 15

Width/Depth

Answer 15

The shorter side of an object

Question 16

Thickness/Height

Answer 16

The measurement not covered by width

Question 17

Drawing Scale is expressed as a ratio; e.g. 1:1 = actual size.

Answer 17

2:1 = Double Size; 1:20 = One 20th; 1:50; One 50th, etc.

Site drawings are often made at a scale of 1:200, even 1:500. Mechanical drawings are often made at 1:1 or 2:1.

Question 18

Block Diagram

Answer 18

A type of flowchart designed to illustrate the layout of an electrical system.

In large installations, a number of Block Diagrams might be used.

Question 19

Circuit Diagram

Answer 19

Often, a circuit diagram will not align perfectly with the circuit itself.

Australia/NZ align with International Standards, but it is still common to see regional differences between other countries.

Question 20

Wiring Diagram

Answer 20

More realistic than a circuit diagram; a wiring diagram shows the terminals and connections of components.

A wiring diagram is used:

• When the installation is wired in the first place
• When a component in the circuit is replaced
• As an aid for fault finding.

Question 21

Ladder Diagram

Answer 21

A form of circuit diagram. The Active and Neutral are drawn as columns on either side, forming the ‘rails’, while the wiring across represents the ‘rungs’

Question 22

Cable Schedule

Answer 22

Not commonly used for domestic situations; a cable schedule is a table presenting information about cable used in an installation.

Information such as:

• Cable length
• Type and size
• Colour
• Termination detail
• To and from devices
• Route
• Conduit detail

Question 23

Title Block

Answer 23

An essential component of every mechanical drawing. The title block contains the following information:

– Company or organization name
– Title of drawing
– Size of the paper used
– Drawing number
– Date the drawing was done
– Sheet number and number of sheets (pages)
– Projection system used.

Question 24

Schematic Drawing

Answer 24

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Question 25

Location Drawing

Answer 25

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Question 26

Location Plan

Answer 26

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Question 27

Site Plan

Answer 27

A site plan is a large scale drawing that shows the full extent of the site for an existing or proposed development. Site plans, along with location plans, may be necessary for planning applications.

Question 28

Single-Line Diagram

Answer 28

A single line diagram, also referred to as a one-line diagram, is usually a single page document that represents a facilities electrical distribution infrastructure. It will have one single line shown for bus (or cable) to represent all three phases.