30-Amp RV Plug Wiring Diagram

30-Amp RV Plug Wiring Diagram — interactive diagram. Open it in the editor to customise components and wiring.

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The 30-amp RV shore-power connection uses the NEMA TT-30 plug and receptacle — a 3-prong, 120 V, 30 A connector with a hot, neutral, and ground pin — providing up to 3,600 watts of power to travel trailers and smaller motorhomes.

North American RVs use two shore-power standards: 30-amp (TT-30) and 50-amp (14-50). The 30-amp system is a single-phase, 120 V circuit and is the most common hookup at campgrounds and RV parks.

NEMA TT-30 plug pin layout (viewed from the plug face, with ground at bottom): - X blade (Hot / Line): the angled blade on the left; connects to the hot conductor (black in North American colour coding). - Y blade (Neutral): the larger straight blade on the right; connects to the neutral conductor (white). - Ground pin (round): the round pin at the bottom; connects to the chassis ground and protective earth (green or bare copper).

The TT-30 is a 3-wire system: Hot, Neutral, and Ground. There is no second hot leg — this is a 120 V single-phase supply, not a split-phase 240 V supply like the 50-amp TT-50 / 14-50 system.

Wiring the receptacle (pedestal side): The hot conductor (black) connects to the X terminal, neutral (white) to Y, and ground (green) to the ground screw. The pedestal circuit is protected by a 30 A breaker in the distribution panel.

Wiring the cord and plug (RV side): The power cord from the RV's converter/power centre terminates in the TT-30 plug. Inside the plug body, black goes to X, white to Y, and green or bare to the ground pin. The conductor size must be rated for 30 A continuous duty — minimum 10 AWG copper conductors in a 3-conductor cord.

Adapter use: Adaptors allow a 30 A TT-30 RV to connect to a 20 A (NEMA 5-20) or 15 A (NEMA 5-15) household outlet for limited power use. The RV's total load must be managed to avoid tripping the smaller breaker. Never use a 30 A adapter at a 50 A pedestal without understanding that you are still limited to 30 A by the cord and RV breaker.

How to wire 30 amp rv plug wiring diagram

Confirm the pedestal receptacle is a TT-30 Look for the distinctive angled X blade slot on the left, the larger straight Y slot on the right, and the round ground hole. Never force a plug into an incompatible outlet.
Inspect the cord and plug for damage Check the cord for cracked insulation, exposed copper, and bent pins on the plug. A damaged cord at 30 A is a fire and electrocution risk. Replace the cord before use if any damage is found.
Plug in the RV power cord at the pedestal With the RV's main breaker off, connect the TT-30 plug to the pedestal receptacle. The plug should seat firmly with no wiggle — a loose fit indicates a worn receptacle that should be reported to the campground.
Check polarity and ground with a plug-in tester Insert a NEMA receptacle tester into the pedestal outlet or into a 120 V outlet inside the RV before switching on large loads. The tester will indicate correct wiring, reversed polarity, or open ground faults.
Turn on the pedestal breaker and RV main breaker Power up in sequence: pedestal breaker first, then RV shore-power inlet breaker, then individual branch circuits. This avoids inrush current spikes from switching all loads simultaneously.
Monitor total load to avoid overloading At 30 A / 120 V you have 3,600 W available. Typical loads: air conditioner 1,200–1,500 W, microwave 1,000–1,500 W, electric water heater 1,500 W. Running all three simultaneously will trip the 30 A breaker.

Specifications

Connector standard	NEMA TT-30 (Travel Trailer 30-amp)
Voltage	120 V AC, single-phase
Current rating	30 A
Maximum continuous load	3,600 W (30 A × 120 V)
Number of conductors	3 (Hot, Neutral, Ground)
Minimum wire size	10 AWG copper (NEC Table 310.15)
Hot pin (X blade)	Black conductor
Neutral pin (Y blade)	White conductor
Ground pin (round)	Green or bare copper conductor

Safety warnings

Always connect the shore-power cord to the RV inlet before the pedestal receptacle, and disconnect from the pedestal first — this minimises arc exposure at the plug.
Never use an extension cord of inadequate gauge as a substitute for a shore-power cord. Undersized extension cords overheat at 30 A continuous load and are a serious fire risk.
Always test pedestal outlets for correct polarity and a functioning ground before relying on them. Reversed polarity can energise equipment chassis and create electrocution hazards.
Electrical work on RV 120 V shore-power systems and pedestals must comply with NFPA 70 (NEC), NFPA 1192 (RV Standard), and local utility or park regulations. Consult a licensed electrician for fixed installation work.
Never connect a 30-amp RV cord to a 50-amp pedestal without a purpose-made, correctly rated adapter. Improvised adapters are dangerous.

Tools needed

NEMA receptacle tester (3-light or digital)
Insulated screwdrivers
Wire strippers
Multimeter
Crimping tool (if terminating a replacement cord)
Torque screwdriver (for terminal screws inside plug body)

Common mistakes

Using an undersized extension cord between the pedestal and the RV, causing the cord to overheat and potentially catch fire.
Connecting Hot and Neutral reversed inside the plug body — creates reversed polarity at every outlet in the RV, which can damage sensitive electronics.
Failing to connect the ground pin, leaving the RV chassis unprotected against insulation faults.
Not checking pedestal voltage and polarity before connecting, leaving the RV vulnerable to overvoltage or reverse polarity damage.
Exceeding the 30 A circuit capacity by running the air conditioner, microwave, and electric water heater simultaneously.

Troubleshooting

RV breaker trips immediately on shore-power connection: Cause: A load inside the RV is drawing more than 30 A, or there is a short circuit in the shore-power wiring. Fix: Turn off all RV loads. Connect shore power. Turn on loads one at a time to identify the overload. Check the shore-power cord and inlet for damage that could cause a short to ground.
Receptacle tester shows reversed polarity: Cause: Hot (black) and Neutral (white) are wired to the wrong terminals in the pedestal receptacle, or the plug was wired incorrectly. Fix: Do not connect the RV until the fault is corrected. Report it to the campground — this is a code violation requiring a licensed electrician to fix. If the fault is in the RV plug, re-terminate correctly (black to X, white to Y).
Shore-power connection is intermittent or RV loses power occasionally: Cause: Loose or burnt contacts in the plug or receptacle, or the pedestal breaker is undersized or failing. Fix: Inspect the plug and receptacle for heat discolouration or melted plastic. A loose or arcing connection generates significant heat. Replace damaged components. Report a faulty pedestal to the campground.

Frequently asked questions

What voltage does a 30-amp RV hookup provide?

A 30-amp TT-30 shore-power connection supplies 120 V single-phase AC, with a maximum continuous load of 3,600 W (30 A × 120 V). This is a single-hot-leg system — it does not provide 240 V like a residential dryer outlet or a 50-amp RV hookup.

What wire size is required for a 30-amp RV cord?

A minimum of 10 AWG (American Wire Gauge) copper conductors are required for a 30 A, 120 V circuit. This applies to the cord set (plug to RV inlet) and any fixed wiring in the pedestal. Undersized wire overheats under continuous load and is a fire hazard.

Can I plug a 30-amp RV into a standard 15-amp household outlet?

Yes, with a purpose-made adapter, but your available power is limited to 1,800 W maximum and practically less for safety. The RV's air conditioner, electric water heater, and other large loads cannot run simultaneously. Never exceed the 15 A breaker's rating or you will trip it repeatedly.

What is the difference between a 30-amp and 50-amp RV hookup?

A 30-amp (TT-30) system is 120 V single-phase with one hot leg, providing up to 3,600 W. A 50-amp system uses a NEMA 14-50 plug with two hot legs at 120 V each (240 V between them), providing up to 12,000 W. Larger motorhomes with multiple air conditioners need 50-amp hookups.

Should I use a surge protector on my 30-amp RV hookup?

Yes. Campground pedestals are notorious for loose connections, reversed polarity, missing ground, and voltage sags or spikes. A hardwired or plug-in surge protector with EMS (Electrical Management System) capability monitors voltage, polarity, and ground faults and disconnects your RV from dangerous conditions before damage occurs.

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