Journeyman Electrician Exam (NEC)General Electrical Knowledge and Plan ReadingMedium
An electrician is reviewing blueprints for a commercial office building. The legend indicates that a dashed line with three short perpendicular lines (─ ─ ─ ─ ─ ╪ ╪ ╪) represents a specific type of wiring. What does this symbol typically denote in electrical blueprints?
- AConcealed wiring in wall
- BExposed conduit
- CUnderground wiring
- DConcealed wiring in ceiling
Show answer & explanationAnswer & explanation
Correct answer: A. Concealed wiring in wall
Standard electrical blueprint symbols use a dashed line with short perpendicular lines to indicate concealed wiring within a wall. The number of perpendicular lines can sometimes denote the number of conductors, but the dashed line form generally means concealed.
Why the other options are wrong
- B. Exposed conduit is usually represented by a solid line.
- C. Underground wiring is often shown as a dashed line with alternating 'U' shapes or specific dashed patterns.
- D. Concealed wiring in the ceiling is typically represented by a dashed line without perpendicular marks, or with fewer/different marks.
Electrical Blueprint Symbols
Standardized graphical representations used on electrical drawings to convey information about devices, wiring, and components.
- Symbols provide a universal language for electricians and engineers.
- A legend on each blueprint clarifies specific symbols used in that drawing set.
- Common categories include outlets, switches, lighting, panelboards, and wiring paths.
Memory trick: Hidden Walls, Dashed Lines with Crosses.