AC keeps tripping breaker

[Geepman]

Went to use my RV’s ac unit today and now it keeps tripping the circuit breaker. It worked fine this morning and now it will not stay operating. I do not want to keep resetting the tripped breaker because who knows when an electrical
fire will start. Any help greatly appreciated. I have a 2021 grand design imagine 3250bh. Thank you.

[TucsonJim]

Hi Geepman. Welcome to the technical forum. I'm assuming you're in an RV park. This is a common problem that is typically related to the RV park's power distribution and not the trailer itself. When many units in the park are trying to run their AC at the same time, the voltage at the pedestal will frequently fall from 120 volts of alternating current to 104 volts or lower.

Using the electrical forumula called Watt's law, Power = Current x Voltage.

Let's say it takes 2100 watts of power to run your air conditioner. If 120V is available, it takes 2100 watts/120V = 17.5 amps. This is fine, and a typical 20 amp breaker will not trip. But if that voltage drops to 103 volts, you now have 2100 watts/103V = 20.4 amps, and the 20 amp breaker trips. I've seen this in a ton of parks.

Trouble-Shooting. I'd suggest you start your AC back up and measure the voltage at the pedestal with a volt meter. If the voltage is below 110V, I'd notify the park that they have inadequate voltage. But based on my experience, there is very little they can do about it.

I'd also suggest that you purchase an Electrical Management System which will shut off power to your coach if the voltage drops too low. Low voltage can cause high current draw in your devices and damage them. An EMS will protect this from happening, but you still won't be able to run the AC when the low voltage situation occurs.

One rather expensive solution is to purchase a Hughes Autoformer which will boost the supplied voltage to a safe level.

Let me know if you have any questions.,

Jim

[Geepman]

We found out that grand design put the wrong size circuit breakers in my travel trailer.

[howson]

We found out that grand design put the wrong size circuit breakers in my travel trailer.

Wow--thanks for the follow up. Did you happen to document the (wrong) size of the breaker and correct size? Also, what was it labeled? Was the repair done under warranty by a dealer or RV technician?

(The moderators can use this info to pass on to GD.)

Howard