To wire a 30 amp RV receptacle, you must use a 30-amp single-pole breaker, 10 AWG copper wire, and a NEMA TT-30R receptacle. This is strictly a 120V AC circuit. The most critical rule of this installation is recognizing that an RV 30-amp outlet is fundamentally different from a 30-amp residential dryer outlet; confusing the two will instantly destroy your RV's electrical system.

The Golden Rule: NEMA TT-30 vs. Dryer Outlets

Before pulling any wire, you must verify your receptacle type. The recreational vehicle industry uses the NEMA TT-30 configuration (Travel Trailer, 30A, 125V). Residential dryers use NEMA 10-30 (older, ungrounded 240V) or NEMA 14-30 (newer, grounded 240V). They are not interchangeable, and adapting between them is a fire and equipment-destruction hazard.

Specification NEMA TT-30 (RV Standard) NEMA 10-30 / 14-30 (Dryer)
Nominal Voltage 120V AC (Single Phase) 240V AC (Split Phase)
Breaker Requirement 30A Single-Pole (1 slot) 30A Double-Pole (2 slots)
Receptacle Face Two parallel blades, one U-ground Two angled blades (and L-ground on 14-30)
Wire Count Needed 3 wires (Hot, Neutral, Ground) 3 wires (10-30) or 4 wires (14-30)
NEC Article Article 551 (RV Parks) Article 210 / 250 (Appliances)

Tools, Materials, and Specifications

Do not substitute gauges or device ratings. A 30A load on 12 AWG wire will overheat and trip the breaker continuously; a 40A breaker on 10 AWG wire defeats the overcurrent protection and risks a structure fire.

  • Receptacle: NEMA TT-30R (e.g., Leviton 306-R or Bryant 9430FR). Rated 125V, 30A.
  • Breaker: 30A Single-Pole (e.g., Square D QO130, Siemens Q130, or Eaton CH130, matching your panel brand).
  • Wire (Indoor/Dry): 10/2 NM-B with ground (Romex). Ampacity rated for 30A under the 60°C column of NEC Table 310.16.
  • Wire (Outdoor/Conduit): Three strands of 10 AWG THHN/THWN-2 (Black, White, Green) pulled through 3/4-inch PVC or EMT conduit.
  • Tools: Non-contact voltage tester, CAT III digital multimeter, wire strippers (Klein 11063 for 10 AWG), torque screwdriver, Phillips and flathead screwdrivers, 1/2-inch or 3/4-inch cable clamps.

Pro-Tip for Long Runs: If your driveway pedestal is more than 50 feet from the main panel, step up to 8 AWG copper wire. A 30A load at the end of a 100-foot 10 AWG run will experience nearly a 4% voltage drop, which can cause RV air conditioner compressors to stall and overheat on hot days.

Mains Safety Protocol

⚠️ WARNING: LETHAL VOLTAGE

Working inside a breaker panel exposes you to lethal mains voltage. Before opening the panel deadfront:

  1. Turn OFF the main breaker to de-energize the bus bars.
  2. Apply a lockout/tagout device if you are not the sole person in the home.
  3. Use a tested CAT III or CAT IV non-contact voltage tester and a multimeter to verify the bus bars are dead by testing from the main lugs to the neutral bar.
  4. NEC-style guidance applies here; if you are uncomfortable working inside the service panel, hire a licensed electrician. Your local Authority Having Jurisdiction (AHJ) may require a permit and inspection for new outdoor receptacles.

Step-by-Step 30 Amp RV Receptacle Wiring

Follow these terminations exactly. The wire colors and their corresponding screws are non-negotiable for establishing the correct 120V potential and ensuring the RV's chassis is properly bonded to earth ground.

  1. Panel Termination (Hot): Route the Black (Hot) wire into the panel. Strip 3/4 inch of insulation. Land the black wire under the terminal screw of the new 30A single-pole breaker. Torque to the manufacturer's specification (typically 12-14 in-lbs for 10 AWG). Snap the breaker into the bus bar stab.
  2. Panel Termination (Neutral): Route the White (Neutral) wire to the neutral bus bar. Strip 3/4 inch of insulation. Land the white wire on an empty terminal screw on the neutral bar. Never land a neutral on a ground bar in a main panel, and never land it on a ground bar in a subpanel.
  3. Panel Termination (Ground): Route the Bare or Green (Ground) wire to the equipment grounding bus bar. Strip 3/4 inch (if insulated green) and terminate under an empty ground bar screw.
  4. Receptacle Prep: At the outlet box, strip the outer jacket of the NM-B cable, leaving 1/4 inch of the inner paper wrapper intact to prevent nicking the wire insulation. Strip exactly 3/4 inch of insulation from the black, white, and bare wires.
  5. Receptacle Termination (Hot): Connect the Black (Hot) wire to the Brass-colored screw on the NEMA TT-30R receptacle. This is the line/hot terminal. Wrap the wire clockwise around the screw so tightening pulls the loop closed.
  6. Receptacle Termination (Neutral): Connect the White (Neutral) wire to the Silver-colored screw. This is the grounded conductor terminal. Ensure no bare copper is exposed outside the terminal pad.
  7. Receptacle Termination (Ground): Connect the Bare or Green (Ground) wire to the Green-colored screw. This bonds the RV chassis to the earth ground via the receptacle yoke and metal box (if applicable).
  8. Secure and Close: Push the wires neatly into the back of the box, keeping the bare ground wire away from the brass and silver terminals. Mount the receptacle to the box, install the weatherproof cover (if outdoors), and restore power at the main breaker.

Verification and Testing

Do not plug your RV in until you have verified the wiring with a digital multimeter. Set your meter to AC Volts (V~) and use the proper testing technique to validate the circuit.

  • Hot to Neutral (Brass to Silver): Expected reading is 120V. (The ANSI C84.1 standard allows a utility tolerance of 114V to 126V). If you read 0V, check the breaker. If you read 240V, STOP IMMEDIATELY; you have wired it to a double-pole breaker.
  • Hot to Ground (Brass to Green): Expected reading is 120V. This confirms the ground path is continuous back to the panel.
  • Neutral to Ground (Silver to Green): Expected reading is less than 2V (ideally < 1V). If you read higher than 2V, you have a high-resistance connection on the neutral bar, a shared neutral causing voltage drop, or a loose terminal at the receptacle.

Finally, plug in a standard 3-light receptacle tester (with a 3-prong to TT-30 adapter, or use a dedicated RV polarity tester). The lights should indicate 'Correct'. If it indicates 'Open Ground' or 'Hot/Neutral Reversed', re-open the receptacle and check your terminations.

The Most Common Botch and Its Symptom

The most frequent and destructive mistake in 30 amp RV receptacle wiring is installing a NEMA 10-30 (dryer) receptacle and wiring it to a 240V double-pole breaker, or wiring a correct TT-30 receptacle to a 240V double-pole breaker because the installer saw '30 Amp' and assumed it needed two hot legs.

The Symptom: The moment you plug the RV into a 240V miswired pedestal, 240V is forced across the RV's 120V hot and neutral bus. The RV's power converter/charger will instantly explode or vent flame. The microwave control board, televisions, and any 120V appliances currently plugged into the RV's interior outlets will suffer catastrophic dielectric breakdown. You will hear a loud pop, followed by the distinct, acrid smell of ozone and melting plastic.

The Fix: This is entirely preventable by strictly adhering to the single-pole breaker requirement and verifying the physical shape of the receptacle slots. As noted in NEC Article 551 guidelines for RV parks, the TT-30 configuration is uniquely keyed to prevent insertion into 240V slots, but using the wrong receptacle or adapter bypasses this mechanical safeguard. Always use a single-pole 30A breaker, 10 AWG wire, and a dedicated NEMA TT-30R outlet.