Tuesday, October 19, 2021

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RVelectricity – Just Ask Mike (J.A.M.): Quick tip to help prevent air conditioner breaker tripping

Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. This week I discuss air conditioner breaker tripping.


Dear Readers,

“The Heat is On” (What a hot song, Glenn Frey.)

With RV air conditioners tripping circuit breakers like crazy with record-breaking heat recently, I’m getting a constant stream of emails and Facebook comments asking what can be done about it. So here’s a tip from our friends at SoftStartRV™ that can help, and it won’t cost you a dime. (Thanks, Danny, for the tip.)

“Hot Town, Summer in the City” (Thanks, The Lovin’ Spoonful.)

Be aware that as the air temperature climbs above 90 degrees, so does the amount of current needed by your air conditioner compressor just to keep running. In my Funkworks Lab I’m seeing at least a 25% increase in the 14 amps or so that a 13.5kBTU air conditioner pulls at 70 degrees F when the temp gets to 96 degrees. Ugh!

“Delta Dawn” (Have I gone too far with the music clichés, Tanya Tucker?)

With the sun beating down on you, you’re now asking your air conditioner to supply a larger Delta T (temperature difference) between the exterior and interior of your RV. So instead of asking it to maintain a 15-degree difference from 90 down to 75 degrees, it could easily be running with a 100% duty cycle when the air temp gets over 100 degrees and still not be able to cool your RV interior below 80 degrees.

A recipe of tripped breakers (I won’t say anything about Julia Child, but I could)…

Just remember that your air conditioner isn’t the only appliance looking for AC power. The other big ticket items are your electric water heater element (10 amps or more), 3-way refrigerator running on 120 volts (3 or 4 amps), and your battery converter/charger (up to 10 amps if you are recharging Lithium batteries). And let’s not forget about the microwave oven (10 to 12 amps), electric coffee maker (9 or 10 amps) or your Instant-Pot (around 10 amperes).

Leaving all or even any those things on while trying to maintain a hospitable environment inside of your RV with your air conditioner while on a 30-amp shore power connection won’t work.

Be aware that your bricks and sticks house with a 200-amp electrical service is actually capable of supplying 400 amperes of current at 120 volts, which works out to 48,000 watts of power (120 volts x 400 amps = 48,000 watts). But your 30 amp RV has only 3,600 watts of power available (120 volts x 30 amps = 3,600 watts).

“Something’s Gotta Give” (Thanks, Jack Nicholson. Hey, it’s a movie – not a song.)

Danny Rahner at SoftStartRV forwarded me an email last week where he solved a customer’s circuit breaker tripping problem by instructing the customer about manual load shedding. That is, turn off all the other energy hogs in your RV if you’re in emergency air conditioning mode.

So turn off your electric water heater element and run it from propane, make sure your 3-way refrigerator is running on propane and not AC power, and even shut off your converter/charger and run from battery power alone during the day, while closely monitoring your RV battery’s SOC (State of Charge), of course.

“Time for a Cool Change” (One more cliché, this time by the Little River Band – sorry.)

I hope this helps keep your RV air conditioner running in the blazing inferno many of you find yourselves in. While this isn’t a perfect solution, it’s at least a temporary fix that can get you though the hottest part of the day.

OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.

Let’s play safe out there….

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
Join Mike’s popular and informative Facebook group.
And you don’t want to miss Mike’s webcasts on his YouTube channel.

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Dave Helgeson
3 months ago

Mike, Can you explain why the compressor draws 25% more amperage at higher temperatures. I have heard this for years, but nobody has been able to explain why.

Thomas D
3 months ago

Years ago, before the advent of central air, window air conditioning was the norm. The condensing coil would get dirty. Leaves bugs cottonwood seeds. Blocking air flow though the coils. Tripping breakers, blowing fuses. We did a great business removing cleaning and replacing air conditioners. Check your air conditioner coils at least once a year or pay a tech to do it. Before the warm season begins

Tommy Molnar
3 months ago

Ya know, I totally forgot about shutting down the converter. Wow. We do all the other stuff though. I have a switch installed to shut down the CON-verter for when I use the IN-verter. I always learn stuff from Mike.

Neal Davis
3 months ago

Great article enhanced by the song tie-ins! The humor of engineers is an intelligent humor. 🙂 Thank you!

Larry Lee
3 months ago

Makes me all the more thankful that Mike, aka our very best electric buddy, was able to block the recent attempt by regulators from forcing campgrounds to install ground fault detectors on 30A and 50A pedestal circuit breakers. You rock Mike. A big THANK YOU from all of us.

Dan
3 months ago

Thanks a lot Mike! Now I’ll have the Little River Band running through my head all day. Another great article by the way.

Bob p
3 months ago

People that have spent their entire life with unlimited electricity find it difficult to understand the limits of 30A RVs. I wonder what all the newer ALL ELECTRIC RVs are going to do to the older campgrounds that are on the borderline with their service when they have several of these Killer Watt RVs in the park all using maximum electricity at the same time. Do you have an opinion on this?