Drawing Fundamentals

Practice questions covering blueprint reading, dimensioning rules, scales, symbols, abbreviations, and drawing disciplines for electricians.

What is the rationale for electricians to learn drawing skills?

To accurately interpret information on prints and drawings that relate a building's systems, which are scaled down for practicality.

In dimensioning, what do arrowheads on either side of a dimension line indicate?

The direction of the measurement.

What is the name of the lines that extend from the feature being measured to meet the dimension line?

Extension lines.

According to the general rule on construction drawings, what unit of measurement is implied if the dimension is a whole number?

Millimetres ($mm$).

According to the general rule on construction drawings, what unit of measurement is implied if the dimension is a decimal number?

Metres ($m$).

What is the correct way to show a dimension of $600$ millimetres on a print without including the unit?

$$600$$

Define 'ratio' in the context of a drawing scale.

A comparison of two numbers by division where the first represents the length on the drawing and the second represents the actual length of the object.

If a blueprint has a scale of $1:50$ and a line measures $250$ mm with a tape measure, what is the actual length?

$12,500$ mm (or $12.5$ m).

What is the rule for representing numbers with more than four digits in metric notation?

A space is used instead of a comma.

What is an electrical 'legend'?

A list of symbols and corresponding definitions usually found on the first page of electrical drawings.

What does the abbreviation 'NMD90' stand for?

Non-metallic dry $90\,^\circ\text{C}$.

What does the abbreviation 'NIC' mean on a drawing?

Not in contract.

What does the abbreviation 'EMT' stand for?

Electrical metallic tubing.

Define the term 'nomenclature' as it applies to construction plans.

The overall system of symbols, abbreviations, and terms used to represent objects, dimensions, and instructions.

What is a 'bearing wall'?

A wall that supports its weight plus the vertical load above it.

What is technical term for a raceway of circular cross-section used to carry electrical conductors?

Conduit.

Define 'plenum'.

An air compartment maintained under pressure connected to one or more distributing or return ducts.

What are 'studs'?

Vertical structural uprights which make up the walls and partitions of a frame building.

List the five drawing disciplines in their standardized order for a set of construction drawings.

1. Architectural, 2. Structural, 3. Mechanical, 4. Electrical, 5. Landscape.

What is the primary focus of structural drawings?

The specific size, type, and location of structural members.

What is a 'site plan' (also known as a plot plan)?

A bird's eye view of the location of the building or installation on the property.

What is the typical scale used for site plans?

$$1:200$$

What is an electrical 'reflected ceiling plan'?

A type of floor plan drawn from a top-down perspective that focuses on the lighting layout.

In a set of construction drawings, which discipline is the only one that uses 'building sections'?

Architectural.

What is the purpose of a 'schedule' in construction drawings?

To provide details for the type of equipment or building material to be installed in a clear table, preventing drawings from becoming cluttered.

What information can an electrician obtain from a 'motor schedule'?

Motor location, horsepower ($HP$), voltage ($V$), and amperage ($A$).

What scale is typically used for floor plans in commercial building drawings?

$$1:100$$

What scale is usually used for floor plans in residential/single-family residence drawings?

$$1:50$$

What is the range of scales used for section and detail drawings?

$1:1$ to $1:20$

Define 'furring strips'.

Narrow strips of wood fastened to a wall or ceiling to serve as a levelling device and provide a base for finishing materials.