Electrical drawings use standardized symbols so anyone can read them. They fall into two groups: building wiring plans (where devices go in a home) and circuit schematics (how components connect).
Common home wiring-plan symbols
- Duplex receptacle — two circles or a circle with lines; a standard outlet.
- Switch (S) — an “S,” with subscripts for type (S₃ = three-way).
- Light fixture — a circle with an X or cross.
- GFCI — a receptacle marked GFCI for wet/protected areas.
- Panel — a rectangle marking the breaker panel.
Common schematic symbols
- Ground — a set of descending horizontal lines (earth ground).
- Resistor — a zigzag (US) or rectangle (IEC).
- Battery / DC source — alternating long and short parallel lines.
- Switch — a break in a line with a hinged segment.
- Capacitor — two parallel lines (one curved for polarized).
Wiring plans tell an electrician where devices and circuits go; schematics show how a circuit functions. Symbol sets vary slightly between standards (US vs IEC), so check the drawing’s legend.
Safety: electrical work is code-regulated and often requires a licensed electrician. This guide is educational.
Frequently asked questions
What’s the symbol for ground? A series of shrinking horizontal lines beneath a vertical line.
Wiring plan vs schematic? A plan shows device locations; a schematic shows how components connect electrically.
Do symbols vary by standard? Yes — US and IEC differ; check the legend.