How to Wire an RV Plug to a 30-Amp Single Pole Breaker

RVs become self-contained homes when plugged in to mains power.

Wiring a recreational vehicle, or RV, plug to a single-pole, 30-amp electrical breaker cannot be done directly. The plug must fit into a dedicated outlet, and the outlet is supplied by the 30-amp single-pole breaker. The plug has a three-pronged male cable end, with two angled flat blades and one U- shaped pin, and has the American National Standards Institute (ANSI) designation of TT-30P. The matching outlet is a three-receptacle female cable end, with the American National Standards Institute (ANSI) designation of TT-30R. The 120-volt, 30-amp single-pole breaker is an ANSI-standard fitment located inside a conventional household breaker box.

Things You'll Need

• Craft knife
• Wire strippers
• Screwdriver
• Voltage tester
• TT-30P plug
• TT-30R outlet
• Type UF--rated wire
• Metal junction box
• Cable clips

Instructions

1. Fit the TT-30P plug to the end of the RV's umbilical shore-power cord. Use your craft knife to trim 1 inch of jacket material from the cord, exposing the three wires. Do not damage the insulation covering each separate wire. Use your wire strippers to remove a 1/2 inch of the insulation from each separate wire, then twist the bared strands of each separate wire so they become three tight, rope-like threads. Remove the fastener from the plug's underside, turn the plug so the pins point away from you, then lift away the plug's top casing. Ensure the three brass pins are not drawn out of their respective housings. Match each wire to each connection by observing the color code and fit using your screwdriver. The black, hot wire is screwed to a brass-colored screw. The white, neutral wire is screwed to a silver-colored screw. The green (sometimes bare), ground wire is screwed to a green-colored screw. Locate a small clamp inside the jaws of the plug, and secure the cord by clamping it down over the cord's jacket material, then replace the top of the plug and the fastener.

2. Fit the TT-30R outlet to one end of the cable, which will be run to the breaker board. Use Type UF--rated wire. Use your craft knife to trim 2 inches of jacket material from the cord, exposing the three wires. Do not damage the insulation covering each separate wire. Use your wire strippers to remove a 1/2 inch of the insulation from each separate wire, then twist the bared strands of each separate wire so they become three tight, rope-like threads. Grip the TT-30R with its pin-slots away from you and match each wire to each connection by observing the color code. The black, hot wire is screwed to a brass-colored screw in the lower right-hand corner. The white, neutral wire is screwed to a silver-colored screw in the lower left-hand corner. The green (sometimes bare), ground wire is screwed to a green-colored screw in the top center. Install the TT-30R into a metal work-box.

3. Fit the 30-amp supply to the TT-30R receptacle to the single-pole breaker. Switch off the 100- or 200-amp double-sized main switches at the top of the breaker box and remove the dead-front panel. Use your voltage tester to confirm power is off to the bank of circuit breakers. Pull the 30-amp circuit breaker that is to be used for the RV plug. Open a knock-out in the breaker box side close to the breaker to be used, and thread the wire inward. Use your craft knife to trim 4 inches of jacket material from the cord, exposing the three wires. Do not damage the insulation covering each separate wire. Use your wire strippers to remove a 1/2 inch of the insulation from each separate wire, then twist the bared strands of each separate wire so they become three tight, rope-like threads. Fix the green wire to the ground block; this is the earth wire. Screw the white wire to the neutral bus-bar; this is the neutral wire. Screw the red or black wire to the 30-amp circuit breaker housing; this is live -- or hot -- wire.

4. Use cable clips to ensure the new run of wire is not a trip hazard and is not exposed to accidental damage. Replace the 30-amp circuit breaker and the dead-front panel, then switch on the main switches. Use your voltage meter to test the polarity of the TT-30R outlet before plugging in your RV.

Tips & Warnings

• If no screws are colored green, attach green or bare wires to the 'U' shaped pin and receptacle and to the breaker box ground block.

• Live electricity is lethal. Use extreme caution when you work inside a breaker box because components and wires above the main switches remain live even after they are turned off.

References

• My RV: RV Electrical Service, Connections and Basic Information
• DA's Place: RV Wiring Diagrams

Resources

• New RVer: Understanding RV Electricity
• RV Stuff USA: 30 Amp Extension Cord