CEA Reading Electrical Blueprints 5 — Questions and Answers
Question 1: On a blueprint, what does the abbreviation 'TVSS' represent?
- Three-Volt Surge Suppressor
- Transient Voltage Surge Suppressor (Correct answer)
- Terminal Voltage Safety Switch
- Timed Voltage Switching System
Correct answer: Transient Voltage Surge Suppressor
TVSS stands for Transient Voltage Surge Suppressor, a device that protects equipment from voltage spikes.
Question 2: On electrical blueprints, a triangle symbol pointing upward at a panelboard typically indicates:
- A step-up transformer connection
- The top or line side of the panel (Correct answer)
- A grounding point
- A delta-connected load
Correct answer: The top or line side of the panel
An upward triangle near a panel or equipment often marks the line (incoming power) side as opposed to the load side.
Question 3: When a blueprint shows 'EQ SP' between lighting fixtures, it means:
- Equal Spacing between fixtures (Correct answer)
- Equipment Specification
- Emergency/Egress Space
- Electrical Quality Standard Point
Correct answer: Equal Spacing between fixtures
'EQ SP' means Equal Space, instructing the installer to distribute the fixtures evenly between reference points.
Question 4: A blueprint specification calls for '#4 AWG CU GND.' What does 'GND' indicate?
- The conductor is grounded neutral
- The conductor is used as an equipment grounding conductor (Correct answer)
- The wire is underground-rated insulation
- The conductor goes to a grounding electrode only
Correct answer: The conductor is used as an equipment grounding conductor
GND designates this conductor as an equipment grounding conductor, providing a fault-current return path for safety.
Question 5: On a wiring diagram (schematic), component symbols differ from a floor plan because they show:
- The exact physical location of each device
- The electrical connections and function of components (Correct answer)
- The conduit routing path
- The mounting height of devices
Correct answer: The electrical connections and function of components
Schematic wiring diagrams depict how components are electrically connected and how they function, not their physical placement.
Question 6: What does 'T-stat' or 'TSTAT' abbreviation on an electrical blueprint refer to?
- Transfer Station
- Terminal Strip
- Thermostat control device (Correct answer)
- Transformer statistics
Correct answer: Thermostat control device
T-stat or TSTAT is the standard abbreviation for thermostat, shown where a temperature-control device will be installed.
Question 7: A blueprint detail shows a conduit penetrating a fire-rated wall with 'FIRE SEAL REQ'D.' This means:
- The conduit must be painted red
- A listed firestop system must be installed around the conduit (Correct answer)
- A fire alarm sensor must be installed nearby
- The conduit must be steel only
Correct answer: A listed firestop system must be installed around the conduit
Fire seal required means an approved firestop material or assembly must seal the annular space where conduit penetrates the fire-rated assembly.
CEA Reading Electrical Blueprints 5
On a blueprint, what does the abbreviation 'TVSS' represent?