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How to Wire a 15A – 125V Outlet – NEMA 5-15 Receptacle

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How to Install a Standard 15A – 125V Receptacle (NEMA 5-15) with Breaker and GFCI Protection

A standard 15A, 120V receptacle outlet is a common electrical fixture used in North American homes to power everyday small appliances and lighting that draw less than 15 amps of current. It features two vertical slots and a U-shaped grounding hole.

The slot configuration consists of a wider, longer left slot (neutral), a narrower right slot (hot), and a round or U-shaped hole (ground). This type of outlet is typically installed on circuits protected by a single-pole 120V, 15-amp breaker or GFCI. A #14AWG for 3 wire configuration including the EGC is used to wire a 15A-120V outlet.

The NEMA 5-15 is a 2P, 3W receptacle capable of handling a non-continuous load of up to 15 amps at 125V, providing a maximum power capacity of 1,800 watts on a single-phase circuit. For continuous loads, it can safely handle 12 amps at 120V i.e. 1,440 watts.

In the following wiring tutorial, we will show how to wire a NEMA 5-15 receptacle using both standard and GFCI breakers. The wiring diagrams also illustrate the correct breaker and wire sizes used with a 15-amp receptacle for both continuous and non-continuous load applications.

The NEMA 5-15 Outlets and Receptacles

The NEMA 5-15R is a 15A – 125V grounded receptacle designed for use with a NEMA 5-15P plug. As the name suggests, the “15” in 5-15R indicates the maximum current rating in amperes, while the “R” stands for “Receptacle” (outlet). Similarly, the “P” in NEMA 5-15P denotes “Plug,” with “15” indicating its maximum current capacity in amperes.

The 15A, 125V duplex receptacle features a 2-pole, 3-wire configuration. It has two parallel vertical slots i.e. the narrower slot for the hot wire and the wider slot for the neutral. In addition, the round or U-shaped hole is used for the equipment grounding conductor (EGC) pin. This receptacle type is commonly used in the U.S., Canada, and other NEC-compliant countries for powering small appliances such as lamps, ceiling fans, and phone or laptop chargers operating on 125V, 15A circuits.

Good to Know: Both 15A and 20A plugs i.e. NEMA 5-15P and NEMA 5-20P can fit into a 20A-120V (NEMA 5-20R) outlet. However, the reverse is not possible e.g. a 20A plug cannot be inserted into a 15A outlet. In short, a standard 20-amp outlet accepts both 15-amp and 20-amp plugs (non-T-slot), but not vice versa.

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How to Wire a Standard 15A-120V Outlet Receptacle
Terminals of Standard 15A-120V Outlet Receptacle

Terminals

There are three terminals in a 5-15R outlet in accordance with UL/CSA.

  • U Shaped “G” Terminal –  (Green Screw): For equipment grounding conductor (EGC – ⏚) – Bare / Green Wire.
  • Narrow / Shorter Terminal (I) on the Right Side – (Brass Screw) – Connects to the Hot Wire – Black Wire
  • Longer / Wider Terminal (|) on the Left Side – (Silver Screw): Connects to the Neutral Wire – White Wire

Electrical Ratings & Specifications

  • NEMA: 5-15R – Straight-Blade, Duplex Receptacle
  • Poles: 2-Poles, 3 Wires Grounding
  • Voltage: 125V Single-Phase AC Supply – 60 Hz
  • Current:  15A – 12A
  • Breaker / GFCI: 15A – 1P
  • Wattage: 1,800 W
  • Wire Size: #14AWG Copper
  • Grade & Material: Residential & Commercial Grade – Composite & Temper-resistant (TR)
  • Termination: Quickwire Push-In & Side Wired
  • Mounting: Flush / Screw Mounting
  • Wiring: Hardwired / Dedicated Circuit

Wiring NEMA 5-15R Outlet

Wiring 15A – 120V Outlet using 1-P Breaker

As shown in the wiring diagram, connect the terminals of the 15A, 125V outlet (NEMA 5-15R) to a single-pole, 15A breaker in a 120/240V main panel as follows:

  • Connect the Hot (black) wire to the shorter/narrow slot terminal with the brass screw.
  • Connect the Neutral (white) wire to the wider/longer slot terminal with the silver screw.
  • Connect the Ground (bare or green) wire to the centered, round/U-shaped “G” terminal with the green screw.

For this configuration, use #14 AWG copper conductors which is suitable size for a 15A circuit and the corresponding NEMA 5-15R outlet.

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How to Wire a 15A - 125V Outlet, NEMA 5-15 Receptacle

 

During installation, tighten all terminal screws to approximately 14-18 in·lbs (1.6-2 N·m) of torque. Strip the insulation from the conductors according to the connection type:

  • Side wire: 3/4″ (19 mm or 1.9 cm)
  • Back wire: 1/2″ (12.7 mm or 1.27 cm)

Wiring a 15A – 120V Switched Outlet

Following the same wiring diagram shown above, a 15A–120V outlet can be wired and controlled using a single-pole, single-throw (SPST) 15A switch.

As illustrated in the figure, the hot (black) wire from the single-pole 15A breaker is connected to the line terminal (hot) of the SPST switch. The outgoing hot wire from the switch is then connected to the brass terminal (Hot side) of the outlet. The neutral (white) and ground (bare or green) wires are connected to the outlet in the same way as in ordinary outlet wiring.

This way, the ON/OFF operation of the 15A – 120V outlet can be controlled using a switch. When the switch is ON, the outlet will be energized (operational), and when the switch is OFF, the outlet will be de-energized (off).

If the breakaway fin tab between the brass terminals of the outlet remains intact, both receptacles will be controlled together by the switch for ON/OFF operation. However, if the tab between the hot terminals is removed, only the upper receptacle of the duplex outlet will be controlled by the switch, while the lower receptacle will remain energized regardless of the switch position.

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Wiring a Switch to an Outlet

 

Good to Know:

Keep in mind that the brass screws (hot terminals) in duplex receptacles are electrically connected to each other through a breakaway fin (tab). Therefore, connecting one brass screw to the hot wire will supply power to the second brass screw as well. In some cases, you may remove the breakaway fin tab between the two brass screws (hot terminals) to split the outlet for specific applications. This configuration can be seen in wiring diagrams for various outlet/receptacle installations and applications.

Wiring 15A – 120V Receptacle with GFCI

According to NEC 210.8, GFCI protection is required for receptacles installed in garages, basements, outdoors, laundry areas, and other wet or damp locations. Specifically, NEC 210.8(A)(1) through (A)(11) mandates that all outdoor receptacles must be installed downstream of GFCI protection, in accordance with Articles 426.28 and 427.22.

When installing a 15A, 120V outlet in any location where GFCI protection is required by code, you have two options to achieve compliance:

Installing a 15A-120V GFCI Outlet

In this method, the same wiring procedure is followed, but instead of using a standard 15A, 120V receptacle, you will install a 15A, 120V GFCI duplex outlet. The wiring configuration for this setup is shown in the following diagram.

Although this method requires the installation of a GFCI outlet, it helps save space in the main panel since you won’t need to purchase or install a separate GFCI circuit breaker.

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Wiring 15A - 120V GFCI Receptacle Outlet

Good to Know: Currently, only 15A and 20A GFCI receptacles rated for 120V are available, typically in NEMA 5-15 and NEMA 5-20 configurations. For 240V outlets, GFCI protection must be provided using GFCI circuit breakers, as 240V GFCI receptacles are not available.

Wiring a 15A-120V Outlet with a GFCI Breaker

If a GFCI outlet is not an option, you can simply remove the standard 15A, 120V breaker and install a GFCI circuit breaker (1-pole, 15A, 120V) instead. The rest of the wiring remains the same as shown in the following wiring diagram.

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How to wire a Single Pole GFCI Circuit Breaker

FAQs

How Many Amps Can a 15A – 120V Outlet Handle Safely?

A NEMA 5-15 outlet is rated for a maximum non-continuous current of 15 amps at 125 volts AC. For continuous loads (lasting 3 hours or more), the NEC recommends using up to 80% of the outlet rating, which equals 12 amps safely.

Good to Know:

  • This guideline is in accordance with NEC Articles 210.19(A), 210.20(A), 215.2(A), 215.3, and 230.42(A), which require branch circuits and feeders to be sized based on the continuous and non-continuous load conditions.

How Many Watts Can a 15A – 120V Receptacle Hold?

At 120 volts, a 15-amp outlet can handle up to 1,800 watts (120V × 15A). For continuous use, limit the load to about 1,440 watts (80% of 1,800W).

Which Breaker Size is Suitable for a 15A – 120V Receptacle?

A 1-P, 15-amp circuit breaker is the correct size for a NEMA 5-15 outlet, as per NEC requirements.

What is the Correct Wire Size and Cable Type to Use with a 15A – 120V Outlet?

Based on NEC Table – 310.16, Table – 210.24(1) & NEC 240.4(D)(4), the suitable wire size is 14 AWG copper (or #12 AWG aluminum) to use with a 15A outlet and circuit breaker. Similarly, for protection of a 15A circuit , the equipment grounding conductor (EGC) can be #14 AWG copper, as per NEC Table 250.122.

The most common cable type is 14/2 NM-B (Romex) for indoor wiring, or 14 AWG THHN/THWN in conduit for outdoor or wet locations.

In simple words, According to the National Electrical Code (NEC), a 15-amp circuit should use #14 AWG copper or #12 AWG aluminum (minimum) for safe operation.

Can I Use Smaller Size AWG than 14 AWG with a 15A Outlet?

No. Using smaller wires (like 16 or 18 AWG) is unsafe and violates NEC standards. Always use 14 AWG or larger for 15A circuits. In other words, It is against code to use #16 and #18 AWG wire size for branch circuits because #14 AWG is the smallest branch circuit conductor allowed in the NEC.

Can I Use a 15A Outlet on a 20A Circuit Breaker and Vice Versa?

Yes, you can install a 15A outlet on a 20A circuit breaker, provided the circuit uses 12 AWG wire and the load does not exceed 15A. However, you cannot install a 20A outlet on a 15A circuit breaker, as it could allow devices that draw more current than the circuit can handle.

Can I Use a 20A Outlet on a 15A Circuit and Vice Versa?

Can a 15A Device be Plugged into a 20A Outlet?

Yes. Most 20A receptacles are designed to accept both 15A and 20A plugs safely. However, a 20A plug can’t be plugged into a 15A receptacle.

Can a 20A Device be Plugged into a 15A Outlet?

No. A 20A plug has a different prong configuration that won’t fit into a 15A outlet, preventing unsafe connections.

Should I Use a GFCI or Standard Breaker for a 15A Outlet?

Use a GFCI outlet or breaker when the receptacle is installed in wet or damp locations (bathroom, kitchen, outdoors, garage, etc.). Otherwise, a standard breaker is acceptable for dry indoor areas.

Can You Install a NEMA 5-15R in a 240V AC Circuit?

No. NEMA 5-15R is designed for 120V only. Operating 120V device on a 240V circuit is dangerous and can damage connected equipment or cause electrical hazards. Alternatively, you may use a NEMA 6-15R for 240V applications.

What is the Recommended Height for Standard Outlet?

The National Electrical Code (NEC) does not specify an exact height for standard (general-purpose) outlets. However, the commonly accepted standard height based on industry practice and local building codes is:

  • General wall outlets: 12 to 18 inches (30 to 45 cm) above the finished floor to the center of the receptacle box.
  • Outlets above countertops (in kitchens, bathrooms, etc.): Approximately 42 inches (about 107 cm) above the floor, or around 18 inches above the countertop surface.
  • Basements, garages, and workshops: Often 4 ft = 48 inches (1.2 m) above the floor for convenience and to keep outlets clear of potential water or obstructions.

Instructions, Precautions & Codes

  • A 15A load can be connected to a 20A outlet. It is permissible to use 15A receptacles if there are two or more receptacles (such as duplex) on a 20A circuit.
  • It is against the code to connect 20A load on a 15A outlet. In addition, A 20A plug will not fit into a 15A receptacle, and attempting to force it in is dangerous.
  • A standard 20-amp outlet accepts both 15-amp and 20-amp plugs (non-T-slot), but not vice versa.
  • According to the NEC Table – 310.16 , 210.24.(1) and 240.4(D)(4), the correct Breaker and Wire size for  a 15-Amp, 120V (5-15R) outlet is #14 AWG copper or #12 AWG Aluminum.
  • Use #14/2 cable (hot wire, a neutral and one ground) for a 15A-120V breaker and receptacle/outlet.
  • Longer runs (when the distance is more than 50 ft (15.25 meters) require an upgrade and larger wire gauge size to compensate for voltage drop.
  • A 15A outlet can be used for a 12A continuous load and a maximum 15A non-continuous load (210.19(A)), 215.2, and 230.42(A).
  • It is against the code to use a 15A outlet to draw 15A on a 10A breaker.
  • It is against the code to use smaller gauge wire sizes (e.g., using 16, 18 AWG) instead of 14 AWG wire with a 15A outlet and breaker.
  • According to the NEC – 310.16, add 20% of additional ampacity for every 100 feet (30.50 meters) of distance (for example between main panel and subpanel) to counter the voltage drop. For distance and ambient temperature rating (Refer to 110.14(C), 310.15(B)(2)), 310.16 and 240.4(A).
  • 15A, 120V outlet can be installed on 15 amp breaker only.

Warning

  • Make sure to disconnect the power supply by switching OFF the breaker in the main panel before doing any electrical work.
  • If you are unsure, contact a licensed electrician to do it according to the local area codes.
  • The author will not be liable for any losses, injuries, or damages from the display or use of this information or if you try any circuit in wrong format. So please! Be careful because it’s all about electricity and electricity is too dangerous.

Resources:

Related Wiring Tutorials

NEMA Family Outlets/Receptacle Wiring

NEMA 5 -Series

NEMA 6-Series

NEMA 10-Series

  • How to Replace a 20A – 120/240V Outlet – NEMA 10-20R
  • How to Replace a 30A – 120/240V Outlet – NEMA 10-30R
  • How to Replace a 50A – 120/240V Outlet – NEMA 10-50R

NEMA 14-Series

NEMA General Outlets/Receptacle

  • How to Wire a 15A – 125V, 2-Wire, Non-Grounding NEMA 1-15 Receptacle
  • How to Replace a 20A – 250V Outlet – NEMA 2-20 Receptacle
  • How to Wire a 30A – 125V Outlet – NEMA TT-30 Receptacle

General Wiring Installations:

Switches Wiring

GFCI/AFCI Breaker/Outlet Wiring

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