Main breaker tripping

[Jeffblanton]

I have a 2011 Passport Lite 235. With the a/c running, if we turn on the water heater or microwave, the main breaker trips out. I have already replaced the main breaker and the 30A plug for shore power. Any help troubleshooting this will be greatly appreciated. Not sure what else to check. Thanks in advance.

[sourdough]

Therein lies the problem with 30A service. You are trying to use high amperage devices at one time. You have to use one of them at a time. Put your water heater on LP.

[Jeffblanton]

Thanks Dan. That's what we have started doing. Any reason you know of as to why this started now? We haven't had this problem in the past. Never had to shut the a/c off to use the microwave before. This all stared about a month or so ago.

[chuckster57]

Do you have an EMS? Energy management system, it will show you how many amps your drawing, and voltage. I suspect your in a lower voltage situation that causes higher amps.

[Jeffblanton]

Unfortunately our model doesn't have EMS. Guess I'll have to do it the old fashion way with an amp clamp. Thanks for the reply

[LewisB]

You may have items running of which you are not fully aware. For example, if your batteries are getting weak (and they do as they age), the converter very well be running and trying to charge the batteries. Other things that can affect the power draw on your electrical system include.
Reduced incoming voltage on shore power (e.g. heavyer community load)
Weather (temperature, humidity, etc.) which causes the AC to "work harder"
Equipment age/condition - as your AC system is used, it "ages" with the motor windings slowly breaking down, etc.
Other unknow items (water heater, converter, all the little battery chargers for cell phones, etc.).
Lights and other 12 V items that cause the converter power draw to increase to the batteries.
If you used to be able to run the AC system and the microwave, you may just have been "lucky" with conditions. For example, you may have started the microwave when the AC compressor was not running (fan only) and the current draw was lower. Generally, on a 30A system you can only run one high power item at any time.

If you have a means to monitor current flow in your system (e.g. a master current shunt and meter like a Victron system), you can make a project of this and shut everything down, turn items on one at a time and check current flow to each item. I think you will also find there is quite a bit of "parasitic" current flow to items that you may not be able to directly control (gas monitors, smoke detectors, etc.).

BTW: if you are plugged in to (any) shore power, you need to get an EMS system (not just a surge protector) for your rig. Low voltage can KILL your AC and other high power appliances!

[sourdough]

The EMS is an aftermarket add on that you purchase. It monitors the incoming electrical system and monitors for problems. If found, the EMS then shuts power off to the RV to prevent damage to components. Every RV should have one.

The EMS (mine) gives me a readout of incoming voltage and amps used per side (50A). It will do that for a 30A as well. It allows you to turn on devices and see just what they are doing to your electrical system.

In your case, you said it had been working. Have you moved? Plugged into a different source? Anything in the park changed? Any of those could affect the quality of the power you are plugged into. On the other hand, as components age they sometimes get less efficient. Maybe the microwave, hwh, AC ...something has become less efficient and started using a bit more power? An EMS will tell you that.

[wiredgeorge]

Had the same issue in my old Cougar. A/C and microwave couldn't be run at the same time else the main popped. I pulled the microwave A/C wires off the breaker panel and to the rear of the camper and connected these to an all weather marine plug. Connect an extension cord to a 15 or 20A outlet on the power pedestal when we hook up and no more popped main.