Electrical Blueprints and Residential Building Framing

Vocabulary terms detailing electrical symbol conventions, blueprint line types, and structural framing components from lecture notes.

As built

A modified blueprint created at the end of a construction job to show the exact finalized locations and wiring details of installed electrical equipment.

Solid line (blueprint wiring)

A continuous line on an electrical plan indicating constant power or an always-hot conductor.

Dashed line (blueprint wiring)

A dashed line on an electrical drawing representing a switch leg that only carries power when the switch is turned on.

Curved dashed line

A curved line running from a switch symbol to a lighting outlet symbol indicating control by that switch, drawn curved so as not to be confused with a building line.

Split wired outlet

A receptacle outlet where one half is continuously energized and the other half is controlled by a wall switch.

WP

An electrical symbol designation indicating a waterproof or weatherproof device or outlet.

Special purpose outlet

A receptacle for equipment not typically found in a standard residential setup, identified on plans by a designated number or letter that corresponds to a spec legend.

Double pole switch

A switch featuring four terminal screws used to control a high-voltage line like $220\,V$ in a manner similar to a single pole switch.

Pilot light switch

A light switch equipped with an indicator light that visually shows whether power is currently supplied to a fixture in a room or enclosed area.

Keyed switch

A tamper-resistant light switch operated only by a special key or tool, commonly used in public spaces like gymnasiums.

Junction Box (J Box)

An electrical enclosure specifically used for connecting and splicing conductors.

Object lines

Solid, dark lines on blueprints that define the primary outline of a building structure.

Dimension lines

Thin, unbroken lines used on blueprints to show the specific physical length or width of an object.

Extension lines

Lines drawn outward from an object line without touching it, between which dimension lines are positioned.

Hidden lines

Straight dashed lines used to denote edges or features of an object that are hidden from the current view plan.

Center lines

Alternating long and short dashed lines used to mark the exact center of structural features like doors and windows.

Break lines

Drawing symbols used to indicate that a full physical object is longer than what is drawn on the page.

Leaders

Angled solid lines ending in arrowheads that point directly from notes or labels to specific items on a blueprint.

Section line

A broad line composed of a long dash followed by two short dashes that marks where a sectional cut view is taken.

Title block

A structured block on the first sheet of blueprints detailing scale, project name, address, design firm, completion date, and sheet numbers.

Architect scale

A three-sided measuring instrument with calibrated graduations used to translate scaled blueprint measurements into real dimensions.

American National Standard Institute (ANSI)

The organization that establishes standard symbols for electrical construction blueprints.

Platform frame (Western frame)

A framing method where each floor is built first as a platform and wall studs are erected directly on top of it.

Balloon frame

A framing method where exterior wall studs run continuously from the sill up past multiple floors, supporting upper floor joists on a $1 \times 4$ ribbon.

Rafters

Inclined structural roof components supported by the top wall plate that form the angle and shape of the roof.

Ceiling joists

Horizontal structural members resting on top wall plates that support ceiling finish materials or act as floor joists for an upper story.

Draft stops (Fire stops)

Lumber inserts installed inside wall cavities or joist spaces to block airflow and slow down the spread of fire.

Top plate

A horizontal lumber framing member at the top of a wall structure, often doubled up ($2 \times 4$ or $2 \times 6$), that supports upper structural elements.

Wall studs

Vertical framing members (typically $2 \times 4$ or $2 \times 6$ lumber) that form the vertical structure of walls and support junction boxes.

Bottom plate

The lowest horizontal piece of framing lumber in a wall section that rests directly on top of the subfloor.

Subfloor

The structural base layer laid over floor joists, commonly built with $4 \times 8$ foot sheets of plywood or OSB board.

Floor joists

Horizontal framing lumber (such as $2 \times 8$, $2 \times 10$, or $2 \times 12$) attached to sills and girders to support the floor load.

Girders

Heavy structural beams made of wood or steel used to bear weight and support the inner ends of floor joists.

Band joist (Rim joist)

A perimeter joist attached perpendicularly across the exposed ends of floor joists to provide lateral rigidity.

Sill

A wood plate bolted directly to the top of a foundation wall that serves as the base fastening point for floor joists.

Sheathing

The exterior paneling attached over wall studs or roof rafters that acts as a base for exterior siding or roofing material.

Foundation

The poured concrete or concrete block base of a building that bears the total structural framework load.

Footing

A poured concrete base underneath foundation walls designed to distribute structural weight into the ground.

Bridging

Diagonal cross-bracing or solid blocking placed between adjacent floor joists to distribute floor loads across a larger area.