Journeyman Electrician Exam (NEC)General Electrical Knowledge and Plan ReadingEasy
A commercial building is being wired, and the electrician is reviewing the electrical blueprints. A specific symbol appears repeatedly, showing a circle with a diagonal line passing through it and an 'S' inside the circle. What does this symbol typically represent?
- ADuplex receptacle
- BSmoke detector
- CSpecial purpose outlet
- DSingle-pole switch
Show answer & explanationAnswer & explanation
Correct answer: D. Single-pole switch
In standard electrical blueprint symbols, a circle with a diagonal line through it and an 'S' inside represents a single-pole switch. Other variations exist for different types of switches.
Why the other options are wrong
- A. Duplex receptacles are typically represented by a circle with two parallel lines extending from it.
- B. Smoke detectors usually have a different symbol, often a circle with 'SD' or specific lines.
- C. Special purpose outlets often have a circle with specific letters or symbols indicating their function (e.g., 'DW' for dishwasher).
Electrical Blueprint Symbols: Single-Pole Switch
A standardized graphic representation on electrical blueprints indicating the location and type of a single-pole switch.
- A circle with an 'S' and a diagonal line is common.
- Used to control a light or device from one location.
- Essential for interpreting wiring diagrams.
Memory trick: Switches are S-circled, outlets are lines, lights are plain circles.