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.
“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.)
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.
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