CEA Reading Electrical Blueprints 2 — Questions and Answers
Question 1: On an electrical blueprint, what does a dashed line typically represent?
- A homerun to the panel
- A conduit run above the ceiling or hidden (Correct answer)
- A low-voltage circuit
- A circuit that is future/not in current scope
Correct answer: A conduit run above the ceiling or hidden
Dashed lines on electrical plans commonly indicate conduit or wiring concealed above ceilings or within walls.
Question 2: What is the purpose of a 'homerun' arrow on an electrical floor plan?
- It shows where the circuit originates at a fixture
- It indicates the circuit route back to the panelboard (Correct answer)
- It marks a junction box location
- It shows the direction of current flow
Correct answer: It indicates the circuit route back to the panelboard
A homerun arrow points toward the panelboard, indicating where that circuit's conductors return for overcurrent protection.
Question 3: On a blueprint riser diagram, what information is primarily shown?
- The floor plan layout of each receptacle
- Vertical routing of electrical systems between floors (Correct answer)
- Grounding electrode system details
- Switch leg wiring configurations
Correct answer: Vertical routing of electrical systems between floors
A riser diagram illustrates how electrical services and feeders travel vertically through a multistory building.
Question 4: Which blueprint symbol typically represents a single-pole switch?
- S with a subscript '1'
- S with no subscript (Correct answer)
- S with subscript '3'
- S with subscript 'P'
Correct answer: S with no subscript
A plain 'S' with no subscript on electrical plans represents a standard single-pole switch.
Question 5: On an electrical plan, what does 'NIC' stand for?
- Not In Contract (Correct answer)
- Neutral In Circuit
- Non-Isolated Conduit
- Normally Inactive Circuit
Correct answer: Not In Contract
'NIC' means Not In Contract, indicating work shown on the drawing that is excluded from the current scope.
Question 6: What does a circle with a cross (+) inside typically represent on an electrical reflected ceiling plan?
- Exit sign
- Recessed downlight fixture (Correct answer)
- Ceiling fan
- Smoke detector
Correct answer: Recessed downlight fixture
A circle with crosshairs commonly represents a recessed downlight or can fixture on reflected ceiling plans.
Question 7: When reading a panel schedule on blueprints, the 'Trip' column refers to:
- The breaker's frame size
- The breaker's ampere interrupting capacity
- The overcurrent device trip ampere rating (Correct answer)
- The number of poles on the breaker
Correct answer: The overcurrent device trip ampere rating
The 'Trip' column lists the ampere rating at which the breaker will open (trip) to protect the circuit.
CEA Reading Electrical Blueprints 2
On an electrical blueprint, what does a dashed line typically represent?