USB Outlet Symbol
Definition: The USB Outlet symbol represents a mains wall receptacle that incorporates one or more built-in USB charging ports alongside (or in place of) standard AC sockets, shown on residential wiring diagrams with two terminals: Hot and Neutral, supplying 120/230 V AC to the AC socket and a 5 V DC USB output via an internal power adapter.
Also known as: USB wall outlet, USB receptacle, USB charging outlet, USB power outlet, combination USB/AC outlet, USB wall charger receptacle.
What the USB Outlet symbol means
The USB Outlet symbol represents a combination electrical receptacle that provides both standard AC mains voltage sockets and USB-A or USB-C charging ports in a single wall-plate unit. The device contains a built-in USB charger circuit that converts the mains supply (120 V AC in North America, 230 V AC in IEC regions) to 5 V DC for charging smartphones, tablets, and other USB-powered devices without requiring a separate plug-in USB adapter.
In residential and commercial electrical wiring diagrams, the USB outlet symbol marks the location of this combined device on a branch circuit, showing that the outlet serves dual purposes — mains power for appliances and direct USB charging. The symbol appears on floor plans and wiring diagrams in the same position as a standard duplex outlet, usually with a label noting the USB port configuration (e.g. 'USB Type-A + A', 'USB-C 30 W', or 'USB-C + A').
How to identify the USB Outlet symbol
The USB Outlet symbol closely resembles a standard duplex outlet symbol — typically two parallel vertical slots with a curved ground slot below, representing the AC receptacle face — but adds a small 'USB' label or rectangular USB port representation on or beside the symbol. On simplified wiring diagrams the symbol may be a rectangle labelled 'USB Outlet' or 'USB Charger Outlet' with Hot and Neutral wire terminals indicated. Some diagramming tools use a standard outlet circle with a 'USB' subscript to distinguish it from a plain outlet.
Function in a circuit
A USB outlet functions as a standard AC wall receptacle for normal appliance plugs while also providing direct USB charging through one or more USB ports built into the outlet body. The internal USB charger circuitry — a compact switch-mode power supply — rectifies and converts the 120/230 V AC input to regulated 5 V DC (USB 2.0) or higher voltages (USB-C Power Delivery). The Hot and Neutral conductors connect to both the AC socket and the internal USB charger. No additional wiring is needed for the USB function; only the standard two-wire (plus ground) mains circuit is required. Output current per USB-A port is typically 2.1–2.4 A; USB-C ports may provide 18–65 W via Power Delivery.
Standards: IEC vs ANSI
| IEC 60617 | No dedicated IEC 60617 symbol exists for USB wall outlets. In IEC/European wiring diagrams they are shown as standard socket outlet symbols (IEC 60617-10 lamp and appliance symbols) with 'USB' annotation. IEC 62368-1 covers safety for audio/video and IT equipment including USB charger circuits built into fixtures. |
|---|---|
| ANSI/IEEE 315 | In North America, USB outlets are governed by UL 498 (receptacles) and UL 2089 (vehicle battery chargers — referenced for USB charging standards). NEC Article 406 covers receptacles; Article 210.52 covers dwelling unit receptacle placement. USB outlet symbols on NEC-compliant wiring plans follow the same convention as standard receptacle symbols with a 'USB' annotation. |
| Key difference | Both IEC and ANSI schematic conventions use a standard outlet symbol with 'USB' annotation for USB outlets — no distinct standardised glyph exists in either IEC 60617 or ANSI Y32.2. Electrical wiring requirements differ: NEC (North America) requires AFCI protection on new installation branch circuits; IEC/BS 7671 requires RCD protection in similar locations. |
Terminals / pins
| Pin | Name |
|---|---|
| hot | Hot |
| neutral | Neutral |
Typical values
Typical specifications: mains input 100–240 V AC, 50/60 Hz; USB-A output 5 V DC, 2.1–2.4 A per port (10.5–12 W); USB-C output 5–20 V (USB PD), 15–65 W; total combined USB output power 15–65 W; AC socket rating 15 A / 125 V (NEMA 5-15R) or 13 A / 250 V (BS 1363). In-outlet USB efficiency typically 80–85%.
Where the USB Outlet symbol is used
- Kitchen and bedside residential outlets replacing standard duplex outlets for convenient device charging
- Hotel room nightstand outlets providing guests with USB charging without requiring plug adapters
- Commercial office USB outlet installations at workstation desks and conference tables
- Airport and transit terminal seating area USB charging stations
- Hospital patient room bedside outlets with USB ports for patient device charging
- Retail and hospitality USB outlet installations for customer convenience charging
Example
A bedroom wiring diagram shows two USB Outlet symbols at each nightstand location on the branch circuit, replacing standard duplex outlets. Each symbol is connected to the 15 A lighting/outlet circuit with Hot (black), Neutral (white), and Ground (green) conductors per NEC 210.12 AFCI requirements. The annotation '2× USB-A 2.4 A' beside each symbol indicates the charging capability without any additional sub-panel wiring.
Key facts
- The USB Outlet symbol represents a combined AC receptacle with built-in USB charging ports, shown on wiring diagrams with Hot and Neutral terminals — no additional circuit wiring is needed for the USB function.
- Governed by NEC Article 406 and UL 498 (North America) or IEC 60884-1 / BS 1363 (IEC regions) for the AC receptacle; IEC 62368-1 and USB-IF specifications for the USB charger circuitry.
- USB-A ports typically provide 5 V at 2.1–2.4 A (10.5–12 W); USB-C ports with Power Delivery may provide up to 65 W at programmable voltages.
- The outlet's internal USB charger is a compact switch-mode supply drawing power from the Hot/Neutral mains connection — no separate low-voltage wiring circuit is required.
- NEC 210.12 requires AFCI protection for bedroom and most living area circuits in new North American residential installations; USB outlets on these circuits must be on AFCI-protected breakers.
- No dedicated IEC 60617 or ANSI Y32.2 symbol glyph exists; the symbol is a standard outlet icon with a 'USB' label or additional USB port graphic added.
- USB outlets can retrofit existing standard outlet boxes (standard 2-gang or single-gang depth); electrical box fill calculations per NEC 314.16 must account for the device's conductor count.
- USB-C ports on modern USB outlets support USB Power Delivery (PD) profiles; the outlet must be compatible with the charger's PD protocol (USB PD 2.0 or 3.0) to deliver advertised fast-charge power.
Diagrams that use this symbol
- usb wiring diagram
- usb cable diagram
- usb cable wiring diagram
- usb connection diagram
- usb a pinout diagram
- usb pin diagram
- usb c wiring diagram
- micro usb diagram
Frequently asked questions
What does the USB outlet symbol look like?
The USB outlet symbol looks like a standard duplex wall outlet symbol — typically two parallel slot shapes with a D-shaped ground slot — with a 'USB' label or small USB port rectangle added to indicate the built-in USB charging function. On simplified wiring diagrams it may be a plain rectangle labelled 'USB Outlet' with Hot and Neutral terminal stubs.
What does the USB outlet symbol mean in a wiring diagram?
The USB outlet symbol means a combination device is installed at that location: it provides a standard AC mains socket for appliance plugs AND one or more USB charging ports that deliver 5 V DC (or higher via USB-C PD) without requiring a separate plug-in charger. Only the standard Hot and Neutral (plus ground) branch circuit wiring is needed.
Do USB outlets need special wiring?
No — USB outlets connect to a standard 15 A or 20 A branch circuit using the same Hot, Neutral, and Ground conductors as a regular duplex outlet. The USB charger function is powered internally from the same Hot/Neutral mains connection. No additional low-voltage wiring is required. AFCI protection may be required by NEC 210.12 depending on the room location.
How much power does a USB outlet provide?
USB-A ports on wall outlets typically provide 5 V at 2.1–2.4 A per port (10.5–12 W), which charges most smartphones at full speed. USB-C ports with Power Delivery capability provide up to 65 W at programmable voltages (5/9/15/20 V), fast-charging compatible laptops and tablets. The total USB output power is printed on the outlet's faceplate label.
Can I replace a standard outlet with a USB outlet?
Yes — USB combination outlets are designed as direct drop-in replacements for standard duplex outlets in the same electrical box. Connect Hot to the brass terminal, Neutral to the silver terminal, and Ground to the green screw — the same as a regular outlet. Confirm the box has sufficient cubic-inch capacity per NEC 314.16 before installation.
What standard covers USB outlet wiring?
In North America: NEC Article 406 (receptacles, cord connectors, and attachment plugs) and UL 498 cover USB outlet installation and safety. In IEC countries: IEC 60884-1 (plugs and socket outlets for household use) and IEC 62368-1 (AV/IT equipment safety) apply. The USB electrical interface follows USB-IF specifications and IEC 62680.
What is the difference between a USB outlet and a standard outlet symbol?
A standard outlet symbol shows AC receptacle slots only. A USB outlet symbol is identical to the standard outlet symbol but includes a 'USB' label or USB port graphic to indicate the built-in charging ports. Both symbols use the same Hot and Neutral wiring connections on the diagram — the USB function adds no additional conductors to the circuit.
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