What is a sectional line commonly used for in architectural drawings?

A sectional line in architectural drawings serves the purpose of indicating where a cross-section of a structure has been made. This line signifies that the section shows a slice or cut through the building, allowing viewers to see the internal details and configuration of various elements within the structure.

By using a sectional line, architects provide a clear visual reference, helping to illustrate materials, dimensions, and relationships between different components in the architecture that would otherwise be hidden in a standard floor plan. This is essential in communicating complex design aspects to builders, engineers, and other stakeholders involved in the construction process.

The other options, while relevant to architectural drawings, do not accurately describe the primary function of a sectional line. Electrical wiring is typically shown using distinct symbols and lines, structural supports would be designated with specific details in the drawings rather than a sectional line, and dimensions are indicated with dimension lines and annotations, rather than by a sectional cut. Thus, the correct understanding of a sectional line's role focuses specifically on its function to depict areas that have been 'cut' for detailed views.