CPI Blueprints, Schematics, & Specifications 3 — Questions and Answers
Question 1: Which type of line on a mechanical drawing indicates a hidden edge or feature not visible from the current view?
- A solid continuous line
- A dashed or hidden line (Correct answer)
- A centerline (long-short-long dashes)
- A phantom line (long-short-short dashes)
Correct answer: A dashed or hidden line
Hidden lines are drawn as evenly spaced dashes to represent edges or features that exist behind the visible surface in that view.
Question 2: A specification calls for conduit installed 'concealed in walls.' If the inspector finds exposed conduit in the same wall, what is the proper course of action?
- Leave it if it passes electrical inspection
- Paint the conduit to match the wall color
- Remove and reinstall per the specification (Correct answer)
- File a change order to update the spec
Correct answer: Remove and reinstall per the specification
Work that does not conform to specifications must be corrected to match the specified requirement unless a formal change order is approved.
Question 3: On electrical drawings, what does the symbol of a circle with an 'X' inside typically represent?
- A junction box
- An incandescent light fixture (Correct answer)
- A disconnect switch
- A ground fault circuit interrupter outlet
Correct answer: An incandescent light fixture
A circle with an X is the standard symbol for a ceiling-mounted incandescent or general-purpose light fixture on electrical floor plans.
Question 4: What is the purpose of a 'cut sheet' or product data sheet referenced in project specifications?
- It documents the contractor's payment schedule
- It provides manufacturer technical details for specified products (Correct answer)
- It lists all subcontractors on the project
- It contains the project safety plan
Correct answer: It provides manufacturer technical details for specified products
Cut sheets are manufacturer-provided documents that detail product dimensions, ratings, installation requirements, and performance data to verify spec compliance.
Question 5: A drawing title block shows 'Rev: C.' What does this indicate?
- The drawing was created by someone with the initials 'C'
- The drawing has been revised three times since the original issue (Correct answer)
- The drawing is a Class C structural document
- The drawing is confidential
Correct answer: The drawing has been revised three times since the original issue
Revision letters (A, B, C…) track how many times a drawing has been updated; Rev C means the drawing has gone through three revisions after the original.
Question 6: What does a 'detail drawing' provide that a general floor plan typically does not?
- Overall building dimensions and room layouts
- Enlarged views with precise dimensions of specific assemblies or connections (Correct answer)
- A list of all materials and their costs
- The project schedule and milestone dates
Correct answer: Enlarged views with precise dimensions of specific assemblies or connections
Detail drawings zoom into complex joints, connections, or assemblies to show exact construction methods and dimensions that cannot be clearly shown at floor-plan scale.
Question 7: On a plumbing isometric drawing, lines are drawn at what angle to represent horizontal runs?
- 0° (true horizontal)
- 30° from horizontal (Correct answer)
- 45° from horizontal
- 90° (true vertical)
Correct answer: 30° from horizontal
Plumbing isometrics use a 30°/30°/90° axonometric projection where horizontal pipes are drawn at 30° to give a three-dimensional appearance.
CPI Blueprints, Schematics, & Specifications 3
Which type of line on a mechanical drawing indicates a hidden edge or feature not visible from the current view?