In terms of 120V troubleshooting, if you are plugged in and lose all power, first measure the voltage directly at the park pedestal outlet. Invest in a home circuit tester; they are inexpensive and can be found at any home improvement store. Using a 30-15A adapter, plug the tester into the park pedestal. It will indicate if the outlet is correctly wired. This simple device, along with a surge protector, can prevent damage or personal injury. Surge protectors are expensive, but well worth the investment. I highly recommend the use of a surge protector, as many RV parks have power problems that can damage your coach or cause injury. Surge protectors are insurance against this.
If the park power checks out, verify the RV circuit breakers have not tripped, especially the main 30 or 50A breaker. Measure the voltage coming into the main breaker. If you have power at the park pedestal, but no power at the main breaker, the problem likely lies with the power cord, or transfer switch if you have one. If you have voltage when using shore power but not when running off generator, check the generator breakers. If you don’t have a transfer switch and need to plug the shore power cord into a generator outlet, measure the voltage at that outlet. If the generator breakers are not tripped and you don’t have voltage at the generator receptacle, the generator is likely not outputting voltage and must be professionally serviced. Otherwise, there may be a problem with the transfer switch. If there is power when running on generator, but not on shore power, and you have ruled out the power pedestal, the problem once again likely lies with the transfer switch.
If you encounter problems with individual 120V circuits in the coach, the problem often lies with the protected GFCI circuits. Many of the branch circuits in a coach are required to be GFCI protected. This includes all external, bathroom, and kitchen outlets, and any other location that may get wet. Only the first receptacle in a protected circuit is required to be a GFCI receptacle, the outlets downstream may be regular outlets. If the first receptacle trips, all receptacles downstream lose power. If you lose an outlet or appliance in your coach, check for GFCI outlets to make sure they are not tripped or damaged. Depending on the size of your coach, you may have one or two GFCI branch circuits, and each one will likely have a single GFCI receptacle, but additional outlets or appliances downstream. This is the single most common cause of 120V circuit problems.
Bear in mind that electronically controlled appliances such as ducted air conditioners with wall mounted thermostats use 12V power for control. If your air conditioner refuses to work, but there is AC voltage present at the air conditioner control box, the problem may be a lack of 12V power. The 12V at the air conditioner is often routed from a nearby light, so once again, be sure to check all the fuses.
Hopefully this series has provided readers with some insight into how to identify and address common electrical problems. Many electrical problems are simple and can be easily traced and resolved by a relatively tech-savvy owner.
About the Author:
Steve Froese, an avid RV owner, traveler, and Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.
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