Duplex Outlet Symbol

The Duplex Outlet schematic symbol. Standard-specific details are listed below where available.

Definition: The Duplex Outlet symbol represents a standard dual-receptacle 120 V AC wall socket used in residential and commercial wiring diagrams, defined under ANSI/NFPA 70 (National Electrical Code) and depicted as a circle with two parallel vertical slots and an optional ground pin, with designator notation typically TR or REC on electrical plans.

Also known as: duplex receptacle, double outlet, twin outlet, wall socket, electrical receptacle, 15A outlet.

What the Duplex Outlet symbol means

The Duplex Outlet symbol denotes a single wall-mounted electrical device housing two independent NEMA 5-15R receptacles, each providing a hot, neutral, and ground connection at 120 V AC / 15 A (or 20 A for NEMA 5-20R). In a wiring diagram, the symbol shows that two devices can be plugged in simultaneously at that location.

The duplex outlet is the most common electrical load-connection point in North American wiring layouts. Electricians and designers place this symbol on floor plans and electrical schematics to indicate outlet locations, circuit assignments, and branch-circuit loading for code compliance under NFPA 70.

How to identify the Duplex Outlet symbol

The duplex outlet symbol in electrical floor-plan notation is drawn as a circle (representing the outlet body) with two short parallel vertical lines inside (representing the two receptacle slots). A curved or straight line may extend from the circle to indicate a wall or mounting surface. In schematic one-line diagrams, the symbol is sometimes simplified to a labelled rectangle with three pins: Hot (L1 in), Neutral (N), and Ground (GND). Some styles add a half-arc or 'D' shape to distinguish it from a single outlet.

Function and usage boundary

A duplex outlet connects branch-circuit wiring (hot, neutral, and ground conductors) to two independent NEMA plug-in receptacles, allowing two portable appliances or devices to draw power simultaneously. The hot pin delivers live 120 V AC, the neutral pin completes the circuit return, and the ground pin provides a safety fault-current path to earth. Tamper-resistant (TR) variants include internal shutters that block foreign object insertion.

Standards: IEC vs ANSI

IEC 60617	IEC 60617 does not define a specific duplex-outlet glyph; general socket-outlet symbols appear in IEC 60617 group 06 (connections), but North American duplex outlets follow ANSI/NEMA standards rather than IEC.
ANSI/IEEE 315	ANSI/NFPA 70 (NEC) Article 210 and ANSI Y32.9 (graphic symbols for electrical wiring diagrams) define the duplex outlet symbol as a circle with two internal lines. NEMA WD-6 specifies the physical NEMA 5-15R and 5-20R configurations.
Key difference	IEC countries use Schuko (CEE 7/4), BS 1363, or regional socket symbols that differ significantly from the ANSI duplex circle; the ANSI duplex outlet symbol is specific to North American electrical drawings.

The displayed SVG is the live editor implementation, not a licensed reproduction or certification of an IEC or IEEE database glyph. Verify the exact official entry and project edition before issuing work.

Logical terminals

Logical ID	Editor terminal name
hot	Hot
neutral	Neutral
ground	Ground

Where the Duplex Outlet symbol is used

Residential bedroom and living-room branch-circuit layouts (required spacing per NEC 210.52: no point along wall more than 1.8 m / 6 ft from an outlet)
Kitchen counter circuits — 20 A NEMA 5-20R duplex outlets on dedicated small-appliance circuits
Home-office and commercial office floor plans showing desk-area power distribution
Garage and workshop electrical plans specifying general-purpose 15 A or 20 A receptacles
Electrical panel-schedule drawings cross-referencing outlet locations to circuit numbers
Building-information modelling (BIM) and CAD electrical layers indicating outlet placement for NEC compliance review

Key facts

The Duplex Outlet symbol represents a NEMA 5-15R or 5-20R dual-receptacle device rated 125 V AC, providing Hot (L1), Neutral (N), and Ground (GND) connections at each of its two receptacle positions.
NFPA 70 (NEC) Article 210.52 requires duplex outlets in dwelling units at intervals no greater than 3.6 m (12 ft) along any wall, making correct symbol placement on electrical plans a code-compliance requirement.
The standard duplex outlet symbol used on North American electrical floor plans is defined in ANSI Y32.9 as a circle with two short parallel lines; the lines represent the two receptacle positions.
Tamper-resistant (TR) duplex outlets, required by NEC 406.12 in all dwelling unit receptacles since the 2008 NEC, are often noted with the suffix 'TR' next to the outlet symbol on construction drawings.
A 15 A duplex outlet circuit (NEMA 5-15R) uses 14 AWG copper wire; a 20 A circuit (NEMA 5-20R) requires 12 AWG wire per NEC 310.12.
The three pins in a schematic representation are Hot (L1 in, x=22/y=0), Neutral (N, x=20/y=60), and Ground (GND, x=0/y=30), reflecting the physical NEMA 5-15 slot arrangement.
GFCI-protected duplex outlets — required by NEC 210.8 in bathrooms, kitchens, garages, outdoors, and near water — use the same circuit symbol with 'GFCI' noted as a suffix or callout.

Frequently asked questions

What does the duplex outlet symbol look like in a wiring diagram?

The duplex outlet symbol is drawn as a circle with two short parallel vertical lines inside it, representing the two receptacle slots. On schematic diagrams it may appear as a labelled box with three connection pins: Hot (L1), Neutral (N), and Ground (GND). A line extending from the circle typically indicates the wall or mounting surface.

What does the duplex outlet symbol mean on an electrical plan?

The duplex outlet symbol marks the location and type of a dual-receptacle 120 V AC wall socket on an electrical floor plan or wiring diagram. It tells the electrician that a branch circuit must be run to that point to provide two plug-in connections at 15 A or 20 A.

What is the difference between a duplex outlet and a single outlet symbol?

A duplex outlet symbol shows two parallel lines inside the circle, indicating two receptacles. A single outlet symbol has only one line. Both share the same Hot/Neutral/Ground pin connections, but the duplex housing accommodates two plugs simultaneously.

What standard defines the duplex outlet symbol?

The duplex outlet symbol for North American electrical drawings is defined in ANSI Y32.9 (graphic symbols for electrical wiring and layout diagrams) and is governed by NFPA 70 (NEC) for installation requirements. IEC 60617 does not include a NEMA-style duplex symbol, as European and international socket standards differ.

What is the designator letter for a duplex outlet?

Duplex outlets do not have a universal single-letter designator like resistors (R) or capacitors (C). On architectural electrical plans they are labelled by circuit number (e.g., circuit 3) and may carry the notation 'DUP', 'REC', or 'TR' (tamper-resistant). NEMA device type codes (5-15R, 5-20R) identify the receptacle configuration.

How many pins does a duplex outlet have in a circuit schematic?

A duplex outlet has three electrical pins in a schematic: Hot (L1), Neutral (N), and Ground (GND). Although the physical device has two receptacle positions, both share the same three conductors from the branch circuit wiring.

What is the voltage and current rating of a standard duplex outlet?

A standard North American duplex outlet is rated 125 V AC at either 15 A (NEMA 5-15R) or 20 A (NEMA 5-20R). The 15 A version is the most common residential type and requires a 15 A circuit breaker and 14 AWG copper wiring per NFPA 70.

Related symbols

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