How to Test 30 amp RV Outlet with Multimeter

how to test 30 amp RV outlet with multimeter

In the RV world, a 30 amp RV outlet or receptacle is a 3-prong male plug that supplies 120V to the appliance through the female RV plug. This guide will show you how to test a 30-amp RV outlet using a multimeter.

30 amp plugs are used in small RV outlets due to normal current requirements, such as air conditioners, microwaves, etc.

An RV outlet has three terminals live, ground, and neutral, as any other outlet, where the live wire supplies 120 volts. However, 50 amp RV outlets have two live wires (each carrying 120 volts), ground, and a neutral wire.

Let’s head toward testing a 30-amp RV outlet…

How to test a 30 amp RV outlet with a multimeter

30 amp rv outlet test

Follow the quick steps:

  1. Set your multimeter to AC Voltage (A〜 or ACV).
  2. Insert the black probe in the ground terminal(D shape).
  3. Insert the red probe in the live (left rectangular terminal).
  4. Also, test the voltage of ground (D) and neutral (right rectangular).
  5. A fine outlet should have around 120 volts in live and ground terminals, while 0 in neutral and ground terminals.

Follow step by step to test a 30 Amp RV Outlet with a Multimeter

Step 1: Set your multimeter

AC voltage symbol on multimeter

Insert the black probe in the COM port and the red probe in the VmAΩ port on the multimeter.

Select the AC voltage setting(A〜 or ACV) on your multimeter with a higher range, such as min 200V.

Turn on the circuit breaker.

Step 2: Insert Multimeter probes in outlet holes(terminals)

Insert the black probe’s metal tip inside an RV outlet’s D-shaped (half-round) ground port.

Place the red probe in the live terminal (rectangular port at bottom left).

If your RV outlet (circuit) is fine, then the multimeter should read 120 volts in the live and ground terminal.

Now we’ll check the neutral and ground terminal for any current leakage.

Place the black probe again in the ground port (D) and the red probe in the live port (bottom right rectangular).

Step 3: Evaluate your RV outlet with multimeter results

If the multimeter reads less than 120 in the live wire, such as around 100. Your RV outlet wiring(either live or ground wire) has been shorted, and the current is leaking.

If the RV outlet’s ground wiring is fine, the multimeter should read as nearer to zero between the ground and neutral wire because the ground and neutral wires don’t supply current. 

A neutral wire is the backway path for current to complete the loop (circuit), and the ground wire or terminal provides safety for electrical hazards.

If the multimeter reads more than a few volts in the ground and neutral wire, then the ground wire or terminal in an outlet is damaged or improperly connected.

Frequently Asked Questions

  1. How much voltage is a 30 amp plug have?

A 30-amp plug has three prongs. It includes a 120-volt hot wire (live terminal), a neutral, and a ground wire. This plug is commonly used for RVs with lower load requirements, such as a microwave or coffee maker.

  1. How to test a 50 amp RV outlet with a multimeter?how to test 50 amp rv outlet

A 50 amp RV outlet male or female plug has 4 terminals; 2 at the left and right are live terminals. The ground terminal is at the top (D shaped) and neutral at the bottom.

Set your multimeter to the AC voltage to test a 50 amp RV plug (male or female). Insert the red multimeter probe inside the ground terminal and the red probe inside both live terminals (left and right). 

Both live wires of 50 amp RV should have around 120 Volts.

  1. How to wire a 30 amp RV plug?

To wire 30 amps plug, screw the ground wire in the D-shaped terminal. 

Now inspect the terminals of the outlet in the actual position(mounted in a device). 

Check the left rectangular port and screw the live wire in it. Screw the last neutral wire in the right rectangular port. At last, screw the whole outlet in the appliance.

  1. How to test the amperage of an outlet?

To test the amperage of an outlet, set your multimeter to AC amps(A). Insert the red probe in the live port and the black probe in the ground port. If your circuit is not damaged or broken, the multimeter will display the amperage of that outlet, such as 30 amps or 50 amps.


Testing an RV outlet is easy if you know the right multimeter settings and tips. Simple measure voltage from the ground terminal to live and neutral terminals and check if both voltage readings are in the ideal range.

Follow an easy step-by-step guide above.

If this article was helpful for you, share it with others and ask your queries in the comments.

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