CEA Reading Electrical Blueprints 4 — Questions and Answers
Question 1: On electrical blueprints, 'EWP' beside a receptacle typically means:
- Equal Wiring Protection
- Exterior Weatherproof (Correct answer)
- Emergency Wall Power
- Extended Wire Pull
Correct answer: Exterior Weatherproof
EWP stands for Exterior Weatherproof, indicating the receptacle is rated for outdoor or damp-location installation.
Question 2: What is a 'detail reference bubble' on an electrical drawing used for?
- Marking junction box locations
- Pointing to a detail drawing with enlarged information on another sheet (Correct answer)
- Identifying circuit numbers
- Showing panel board locations
Correct answer: Pointing to a detail drawing with enlarged information on another sheet
A detail reference bubble contains a number and sheet reference, directing the reader to a larger-scale detail on another drawing.
Question 3: On a three-phase electrical system single-line diagram, three parallel lines represent:
- A three-wire single-phase system
- A three-phase feeder or circuit (Correct answer)
- Three separate neutral conductors
- A triple-pole breaker only
Correct answer: A three-phase feeder or circuit
Three parallel lines on a single-line diagram indicate a three-phase conductor arrangement for feeders or branch circuits.
Question 4: When a blueprint note says 'BY OWNER' next to a piece of equipment, it means:
- The electrician owns that equipment
- The building owner supplies that equipment, not the contractor (Correct answer)
- The equipment is existing and to remain
- The owner must approve the equipment location
Correct answer: The building owner supplies that equipment, not the contractor
'By Owner' means the equipment is furnished by the building owner, and the electrical contractor only connects it.
Question 5: What does 'AIC' rating on a panel schedule indicate?
- Ampere-hours In Circuit
- Ampere Interrupting Capacity of the overcurrent device (Correct answer)
- Automatic Isolation Contactor
- Alternating Intermittent Current
Correct answer: Ampere Interrupting Capacity of the overcurrent device
AIC (Ampere Interrupting Capacity) is the maximum fault current a breaker can safely interrupt without damage.
Question 6: On an electrical site plan, 'UG' next to a conduit run means:
- Ungrouped conductors
- Underground installation (Correct answer)
- Ungrounded circuit
- Under guardrail routing
Correct answer: Underground installation
UG stands for Underground, indicating the conduit is buried below grade rather than installed above ground.
Question 7: A 'phantom line' (long-short-long dash) on an electrical blueprint typically indicates:
- Future or alternate work (Correct answer)
- Existing work to be demolished
- Equipment by others
- Low-voltage wiring
Correct answer: Future or alternate work
Phantom lines represent future equipment, alternate configurations, or work not included in the current construction phase.
CEA Reading Electrical Blueprints 4
On electrical blueprints, 'EWP' beside a receptacle typically means: