Dear Mike,
My question isn’t as technical as the others… so here goes. I live full-time in my 38′ 5th wheel toy hauler with a 50-amp shore power connection. It also has an Onan 4400 generator if I need it. Where I’m parked, it is switching from flat-rate electric to metered. The pedestal has both 50-amp and 20-amp, 120-volt outlets. Is it cheaper to use the 120-volt outlet with an extension cord for small appliances and microwave? Only one at a time—I unplug things I’m not using unless it’s a fan. Thank you for your time. —Christie
Dear Christie,
That’s a great and timely question. The quick answer (for those of you who don’t want to read the full explanation) is no, it doesn’t matter which receptacle you plug into. You can plug a 120-volt appliance into one of your RV’s internal outlets and you’ll use exactly the same kWh (kilowatt hours) of electricity compared to plugging the same appliance directly into the 20-amp outlet on the pedestal.
Just like for your sticks-and-bricks house, the entire panel is being metered for kWh usage. So everything plugged into an outlet in your house (or in your case, the pedestal) will be metered (and billed to you) exactly the same amount.
How does this work?
Here’s a basic wiring diagram of how the 50-amp shore power outlet in the pedestal is split up into the various appliances and electrical systems in your RV.
The pedestal supplies your RV with two separate 120-volt legs which are 180 degrees out of phase with each other. That allows the power panel to be wired to supply either 120 or 240 volts to the load.
However, in nearly every RV on the road, the power panel is wired to supply ONLY 120-volt loads. So that’s one hot leg plus the neutral conductor feeding each air conditioner, battery converter, and all 20-amp electrical outlets in your RV. There are a few exceptions for large coaches wired with 240 volts, but these are pretty rare birds.
What is the meter measuring?
The metered pedestal is measuring the TOTAL amount of electrical energy (kWh) passing through the entire pedestal circuit. So it doesn’t matter if you plug into the 50-amp outlet, the 30-amp outlet, or the 20-amp outlet. If you used 10 kWh of energy, and they’re billing you at 15 cents per kWh, then you’ll owe $1.50 for that usage. And again, it doesn’t matter if you plug your slow cooker into the pedestal directly or an outlet inside of your RV. The meter only sees the TOTAL amount of energy passing through the pedestal.
How can you reduce your energy bill?
First of all, forget about any of the scam devices on the market that say they can reduce your electric bill by up to 85%. If that were true then you would be stealing electricity from the campground. And that’s a bad thing you never want to do. But be assured they don’t work anyway, so save your money.
What can you do to reduce your electric bill?
Just like in your sticks-and-bricks house, you can do a number of things to help reduce your electric energy costs.
Park in the shade if you can: That’s not always possible, but that will certainly reduce the load on your air conditioner.
Forget about the air fryer: While these work great, they typically draw around 1,500 watts of power for 20 or more minutes at a time. So every air frying session could cost you up to 1 kWh of energy. Depending on the local rate, this could cost you between 15 cents and 50 cents every time you make those tasty no-fat fries.
Turn off your water heater: If you only need hot water for showers in the morning, then don’t leave the water heater on all day and night. Turn it on an hour or two before you need it, then power down.
Turn off your air conditioner when you leave: I see lots of unattended RVs with air conditioners running and windows open at the same time. Yes, I can understand that if you have a pet inside you’ll need the air conditioner during the day, but I’ve checked and that’s not usually the case.
Learn how to save…
There’s a LOT more ways to save on electrical power usage. You just need to use your head and monitor what you’re wasting.
One of the easiest ways I’ve seen to monitor your own energy usage is the smartphone app for the Hughes Power Watchdog surge protector. This not only shows you instantaneous voltage and amperage your RV is using, it also adds up the total kWh usage for your entire RV. That means you can turn on one appliance at a time and see just how many amps and kWh it takes. Then you can decide if it’s worth the expenditure.
Electric heaters are power hogs!
Some of the big ticket items are portable electric space heaters and electric fireplaces. These can easily add $100 to your electric bill each month, so you’ll want to find better ways to keep warm in the winter. Plus portable electric heaters can cause a fire if the plug or outlet is worn, oxidized or connected to a power strip.
Let’s play safe out there - Mike
So on a 50 amp service and you have one leg pulling 10 amps and the other leg pulling 35 amps does the meter read the total amps or the the highest leg?
I sure enjoyed the article! It does leave me with a question though. Why has it taken so long for the industry to think about energy efficiency?