Among the common hiccups that RV owners might come across, trouble with the generator switches aren’t unheard of. The transfer switch is the component that lets the onboard generator operate as long as there is not a supply of shore power. When shore power is connected, the switch activates and shuts off the generator.
This saves the generator energy so that it’s not running all the time, and it saves work for you. You won’t have to worry about manually switching it, meaning it won’t run unnecessarily. However, the automatic transfer switch (ATS) can malfunction from time to time. This is inconvenient, as it could hinder the entire power system in your RV.
To troubleshoot your RV generator transfer switch, you may need to calibrate your meter and check the 600-volt AC setting in your ATS. This will help you determine if you need to replace your pedestals, cord sets, and adapters. You may need to check the relay, the timer circuit, and the circuit breaker.
RV Generator Transfer Switch Troubleshooting
Before you begin troubleshooting your RV generator transfer switch, be prepared to play it on the safe side. Know that this involves working with an open electrical panel. Wear a pair of insulated rubber gloves, and keep wood near you in case of possible electrocution.
If you are not qualified or trained to undergo these tests, call an electrician instead. If you do not have experience working with electrical panels and components, don’t run these tests yourself. It’s better to pay a bit of money and wait for an expert to arrive than to potentially endanger yourself.
There are a few tests that you can run to see where the transfer switch failure has occurred. For these, it might be best to run them each one at a time, and in the order they are presented. This will give you a clearer understanding of your generator’s functioning.
Test 1
For this test, you’ll need to calibrate your meter. The purpose is to check incoming shore power between the red and white, black and white, and black and red wires inside the switch box.
Calibrate the meter to the 600-volt AC setting and examine the incoming shore power. If you’re hooked up to the pedestal electricity and the circuit breaker, it should read 120-volts AC from white to red and white to black.
As for the black and red wires, they should read roughly 240-volts on the 50-amp service. If you’re finding these readings to be off, the issue is with your pedestal, adapters, or cord set.
Solution
The solution to this is simply to have the problematic parts replaced. You’ll be able to find pedestals, cord sets, and adapters online, either from major shopping websites like Amazon, or form RV supply stores.
Test 2
For this test, start up your RV’s generator. Make sure your meter is still set to 600-volt AC. If you conducted the previous test already, you can leave it where it is. What you’ll be doing here is testing the incoming power from the generator. You’re looking to see if anything is preventing the generator from producing power.
You should see a measurement of 120 volts between red to white and black to white. As for within the black to red, that will depend on if you wire your generator to be 120/120 volts or 120/140 volts. In general, however, it should be between 0 volts or 240 volts.
If you don’t measure any voltage at all, that means your generator isn’t able to produce power. A likely culprit here is the circuit breaker. Look over the breaker to make sure everything is in its correct place and that it hasn’t corroded or been otherwise damaged.
Solution
If giving your circuit breaker a look and trying to clean it still doesn’t produce the correct voltage, you might need to replace it. This is something that should be trusted to an electrician unless you are capable of doing it yourself.
Test 3
For the third test, you’ll want to calculate the outgoing voltage to the RV’s load center wire while the generator is off.
With the generator turned off, measure the voltage that heads through the load center wire. Whatever your reading is should be the same as your readings from the first test. 120-volts AC from white to red and white to black, and 240-volts for the black and red wires.
If you see a discrepancy in your readings, that means you might have a loose connection. It’s also possible that the relays have burned out. The relays are what controls the pedestal’s energy, and when they fail, as does the rest of the generator.
Solution
First, try to secure the connection by ensuring that all wires are firmly in place, and have not been damaged anywhere. If tightening that connection doesn’t help, you might need to replace the pedestal relays.
These are fairly easy to find online. Reference your generator owner’s manual to verify that you’re selecting the correct ones that will work for your make and model.
Test 4
For this step, you’ll need to turn your generator back on and wait approximately 20 seconds. Waiting will give the controller the chance to time out. While doing this, try to watch the relay kicking in, indicating that the RV’s power is coming from the generator.
If you don’t see the relay kicking in, then the timer circuit in your ATS is to blame. It’s also possible that the relay coil is opening up, or has already done so.
Solution
You might need to close and repair the relay coil. If you’re not capable of doing so, call an electrician or specialist. If it’s not the relay coil, replace the timer circuit in your ATS system.
Test 5
Keep the generator powered on and the relay connected, measure the outgoing voltage to the RV’s load center wires. In this test, you should see the same readings you did in the second test.
Each leg should have the same voltage. If only one has 120-volt, but the other has 0, you might have a burt contact within the generator relay. If this is the case, you may need to replace the transfer switch system entirely. This is unfortunate, but not impossible to do.
It could be that you have to replace the relay, though these can be difficult to get your hands on.
Solution
Find a new ATS system to replace your old one. It may be best to consult an electrician for the installation.
Conclusion
Your ATS system is a complex electrical component that helps your generator switch on and off when connected to shore power. It is a convenient tool that helps sustain the life of your generator. When your RV generator transfer switch runs into issues, there are a few steps you can take to troubleshoot it.
For the most part, you’re going to be looking at the voltage inputs and outputs, and how they behave between the cord sets. The relay is often the cause for trouble with the RV generator transfer switch. It can also stem from problems with the pedestal or circuit board.
If you’re not qualified or trained to handle electrical parts and open electrical panels, be cautious when troubleshooting your ATS. Call an electrician if you’re not 100% confident in your ability to handle these components safely.
