In typical plan drawings, which item is shown as broken lines at intervals with a letter?

• A. Electrical Circuits
• B. Water Supply Lines
• C. Utility Lines
• D. Structural Beams

Answer: (C)

Plan drawings use dashed or broken lines to indicate items that aren’t visible in the current view, with a letter along the line pointing to a legend that identifies the exact type. Underground utilities fit this pattern because you can’t see them on the surface, so they’re drawn as segmented, broken lines and labeled so the legend can specify whether it’s gas, water, sewer, electrical, etc. This convention helps quickly communicate what lies below and keeps the drawing readable.

Electrical circuits, water supply lines, and structural beams are typically shown with different conventions—electrical plans use symbols and specific wiring notations, water lines are usually solid or color-coded, and structural beams appear as continuous solid lines—so they don’t use broken lines at intervals with a single identifying letter in the same way utilities do.