This is an introductory guide to RV 110 volt troubleshooting

First and foremost safety precautions should always be exercised when working with electricity, particularly 110 VAC because it can not only cause serious injury but it can also kill so 110 volt troubleshotting should not be attempted by the inexperienced. For those who are not experienced with electricity its as simple as getting help. Most likely you have a friend or acquaintance who would be glad to show you the "do's" and "don'ts" of AC troubleshotting or you could take a course at a local community college or vocational school. Do not attempt this till you do one or the other.Anyone with the desire can learn these things so you are not doomed to taking your RV to a service center every time a problem rears its head.


The tool you'll need in AC troubleshotting is a decent multimeter or VOM (volt ohm meter). A RMS meter really isn't necessary unless you need accurate readings from a non-sine wave AC power source such as an inverter.

OK, let's get started!

STEP ONE: Check for "good" voltage at the source, where ever you're plugged into. 110-120 volts is normal

The above is a typical 30 amp plug. The round hole at top is ground, with hot and neutral on the bottom where you would place your VOM probes.

This is a 50 amp plug. Again ground is on top, the left and right slots are 110 Volt hot legs(50 amp is actually 220 volts) and common is the lower leg. Here take your reading from common to each 110 volt leg.

STEP TWO: Check for voltage at the main breaker box in the RV.


  • Exercise caution here because its "live" when you're doing this


  • Look for obvious problems such as loose or burnt wires. If wires are secure and in place take a reading between the hot(black) wire and neutral (white) wire. Reading should be about the same as at the power source.
  • (Note: If there is an inverter in the coach you may have an isolated neutral, isolated that is from the regular neutral bus bar so if you run across this it is normal.)


  • No voltage at breaker box.

  •  This means there is an "open" or break in the circuit somewhere between shore plug in and the breaker box




  • Shore line plug in Check the condition of your power cord plug and the receptacle you're plugging into. Are the blades and the receptacle clean and in good condition? If not don't be surprised if you experience any type of power problem.



  • Inspect your power cord - both ends and in between>Sometimes problems are obvious...and sometimes not so obvious. It could be a break or partial break near the plug as this is a high stress area. (Intermittent electrical problems can be caused by a partial break near the plug depending upon how the cord might be twisted or turned. If you suspect your cord spend some time changing the position of the cord and see if there is a pattern of continuity and not continuity.)



  • ATS (Automatic Transfer Switch)


    If the coach has a generator there is a switch somewhere, automatic or manual, depending upon the age of the coach which regulates which power source is being used. (You sure don't want BOTH at the same time). If you have power from one source (generator or shore power) and not the other your problem in probably right here. Depending upon your expertise you may want to stop here. They're not always easy to get to or to diagnose.

REMINDER: Older coaches equipped with a generator may need the power cord plugged into an outlet usually located in the power cord storage area. Also if you have no power from the generator be sure the breakers at the generator are turned "on".




    An inverter can cause an open Having power in some areas and not others is a tip off it could be the inverter


STEP THREE: Check for voltage out of main breaker box.


      Check all breakers - switch them off and on a number of times to insure they're working. Next check for output voltage on the load side. (This is the black wire coming off of each single breaker going to its respective load.)


If the breaker panel is marked and you're experiencing a power problem in one specific area you already know which breaker to check. If not you'll have to figure it out through the process of elimination.

If you have power into the breaker it is unlikely you have no power out. (ie. all the breakers being bad.)

REMINDER If you have power in and no power out be sure MAIN BREAKER is on and operating correctly.



    No voltage at the load side of a particular breaker.



Here is a typical 30 amp breaker box to help illustrate what we're discussing. On the left is the incoming ground (green) wire going to the ground bus bar. Also note the incoming neutral(large white wire) going to the neutral bus bar along with other neutral load wires attached. Looking carefully you will note the hot incoming(large black wire) looping down and up to the left most breaker.(main breaker) The other three breakers comprise the three separate 110 circuits in this RV. Incoming voltage reading would be taken at the neutral bus bar and at the bottom of the main breaker. To test other breaker operations reading would be taken at the bottom where the load wires are attached and the neutral bus bar. 

Above is a typical 50 amp breaker.(There was no inverter in this coach) Note the 2 incoming hot legs (large RED and BLACK wires) going to the two main breakers for this coach. Also note the neutral bus bar in the foreground with the ground bus bar immediately behind it. The incoming ground wire is difficult to differentiate but it is on the left with the 2 incoming hot wires. Here again VOLTAGE READINGS are taken between neutral and hot. 


  • incoming voltage- at the bottom of the two main breakers(on the far left)

  • outgoing voltage- at the bottom of any of the other breakers which is "load side" for the rest of the 110 circuits.


 all power (shore cord and inverter)

 Check for continuity through the breaker.

Disconnect black wire from the load side of breaker.

Check for continuity through the breaker.

Go to hot bus bar (if so equipped) and check for continuity from there to the load side of breaker (where you disconnected the black load wire.)

No continuity...replace breaker.


Voltage out of circuit breaker and yet no operation at the load (appliance, outlet, etc)


    This means there is an "open" or break in between the breaker and the load. Next step is to check all junction boxes in the circuit. (This would be at the air conditioner, water heater, if equipped for AC, junction box under slide for AC outlets, etc, etc.



Check for loose wires, burnt wires, or burnt wire insulation.

Remove wire nuts, separate wires and check for voltage between black (hot) wire and neutral (white) wire.

No voltage then there is an open between here and breaker box. Anytime you're in a junction box suspected of an "open" pull wire nuts and retighten and wrap with electrical tape. Could be another junction box, a pinched, broken or pierced wire somewhere in between. If you trace it to this point you may want to refer this headache to an RV technician.

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