What should 30 amp handle

We were work kamping at a Methodist Camp and hooked up to a 30 am connection. I had our Refrigerator on electric, water heater on electric and running two 15 amp electric heaters when it got cold without any issues. Also used the Microwave from time to time and the Keurig Coffee maker without any issues. We had to relocate because their water lines are not buried deep enough and will freeze.


Moved to our new place where we plan to winter and when asked if we wanted 30 or 50 amp, I went with 30, thinking I only had to worry about 50 amp if I wanted to run 2 AC units.
Doing nothing different, but I have now tripped the breaker twice...........now my questions.........I had no problems at the other 30 amp hook up, but am having problems here, any idea why? I am using two 1500 watt standing oil heaters, running the fridge and water heater on electric, but kickig the breaker if I used the coffee maker or microwave............is that normal.

30 amps at 120 volts = 3600 watts. Add up the wattage of everything you mentioned and it grossly exceeds 3600 watts. The water heater doesn't run all the time, nor does the refrigerator, so you might get by depending on how lucky you are as to when the various appliances need power.

If the voltage at this campground is lower, you'll pull more amps using the same appliances, and will trip the breaker sooner.

But basically, you're trying to use more than 30 amps will supply.

Change the refrigerator and water heater to propane mode to cut power usage. Run your furnace instead of 1500 watt heaters to further reduce the power consumption.

Maybe the supply circuit breaker at the Methodist camp wasn't tripping when it should have.

Its surprising to see how much current is actually being used at times. I know we shut off the electric water heater, when we use the micro wave. And when DW uses her hair dryer, that thing draws 10 amps! Then there is the fireplace, or space heater which draws either 7 or 12 amps. It adds up fast.

We were camping last year in the cold, and we had fireplace and space heater running. When the breaker finally did trip on the 30 amp service we were plugged into. The hot prong on the cord was melted, and the socket in the post was also burnt and smoking! The breaker was old, and it obviously did not trip fast enough.

sengli said:

Its surprising to see how much current is actually being used at times. I know we shut off the electric water heater, when we use the micro wave. And when DW uses her hair dryer, that thing draws 10 amps! Then there is the fireplace, or space heater which draws either 7 or 12 amps. It adds up fast.

We were camping last year in the cold, and we had fireplace and space heater running. When the breaker finally did trip on the 30 amp service we were plugged into. The hot prong on the cord was melted, and the socket in the post was also burnt and smoking! The breaker was old, and it obviously did not trip fast enough.

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Your burnt up plug/socket was most likely a result of RV Plug Arc Syndrome. When people arrive at an RV site and plug in their power cord with the park outlet breaker ON, an electrical arc happens on the plug/socket metal contacts due to the live electrical loads in the RV (battery charger at minimum, all the AC stuff you left turned on, at maximum). This electrical arc causes pitting and corrosion on both the plug and outlet. Using the shorepower current causes heating of the compromised electrical connections. High current use causes the most heating. Heat on pitted, corroded, electrical connections causes more corrosion, more resistance, and more heat, until it ultimately fails. BTW, this arcing also occurs when you disconnect a live circuit from your RV when leaving.

Unfortunately you can't undo the socket damage done previously by other RVers. I have plugged in a new plug into an evidently corroded park socket and had the plug prongs burned black by the next morning. What you CAN do is always turn off the campground outlet circuit breaker/switch before plugging in or unplugging your RV thus preventing plug/socket arcing. I also do extra things like spraying the plug/socket with Caig Cramolyn DeOxIt electrical contact restorer/cleaner before plugging in, then plugging and unplugging the plug/socket about 5 times BEFORE turning on the campground power. I also turn (off first/leaving - on last/arriving) the inside mains breaker on the RV to protect the Progressive power protection internal contactor relay along with the generator transfer switch transfer relay contacts from experiencing the load switching arc, as these parts are expensive and difficult to access/service. My compromise is that the mains breaker switch that experiences the load arc is available at hardware stores, easy to access, and replace.

I know that I cannot run the air conditioner and my wife's hair dryer at the same time. It will run for a few seconds and that is about all. Generally there are some other small items running so it may just take it over with the blower.

If living 30 amp service is a big headache, you might consider INVESTING in a Progressive Industries EMS-HW50C power protection system. Yes, it is pricey, but it protects your electrically operated devices from high voltage, low voltage, spikes, and frequency shifts. If its computer detects one of these problems your rig is removed from the power line in milliseconds, and kept disconnected until the power is stable for 30 seconds. The big bonus for 30 amp services is the remote readout that you can mount inside (like mine) and see a continuous readout of voltage and amps used on each phase, power frequency, and any current or immediately previous line power errors. Watching the readout you can prevent those outside breaker trips.

See: http://www.progressiveindustries.net/ems-hw50c

I just paid for the upgrade to 50 amp. Seemed the easiest thing to do. Just wanted to make sure it was an actually necessary and not just a weak 30 amp plug in. Sounds like we were definitely exceeding 30 amps.....thanks for the information.

danemayer said:

30 amps at 120 volts = 3600 watts. Add up the wattage of everything you mentioned and it grossly exceeds 3600 watts. The water heater doesn't run all the time, nor does the refrigerator, so you might get by depending on how lucky you are as to when the various appliances need power.

If the voltage at this campground is lower, you'll pull more amps using the same appliances, and will trip the breaker sooner.

But basically, you're trying to use more than 30 amps will supply.

Change the refrigerator and water heater to propane mode to cut power usage. Run your furnace instead of 1500 watt heaters to further reduce the power consumption.

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Dan - running with this train of thought...and THANK YOU for explaining it in layman terms... now I understand the conversion of amps to watts, but I don’t believe this is the same equation for our 50 amps. Please explain the 50 amp conversion and watt usage..thx

P=I x V or Watts = Amps X Volts brings back my basic electronics classes Thanks Dan.

Mrsfish said:

Dan - running with this train of thought...and THANK YOU for explaining it in layman terms... now I understand the conversion of amps to watts, but I don’t believe this is the same equation for our 50 amps. Please explain the 50 amp conversion and watt usage..thx

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Ann, there are 2 differences between 30 amp and 50 amp service.

The first difference is the obvious one: 50 is more than 30. 30 amps * 120 volts provides 3,600 watts of power. 50 amps * 120 volts provides 6,000 watts.

The second difference is that with 50 amp service there are 2 separate hot wires, each providing 6,000 watts for a total of 12,000 watts. With 30 amp service there is only 1 hot wire.

So the comparison is 12,000 watts for 50 amp service to 3,600 watts for 30 amp service.

You can see this with receptacle illustrations on page 6 of our Electrical User Guide.

I was at at menards the other day, in the electrical area. The customer was looking at adding a RV plug in to his house. I over heard them saying it was 240V they were going to need to wire this up. I stopped them and explained that it was not 240AC connection they needed, but they looked at me like I was stupid.

sengli said:

I was at at menards the other day, in the electrical area. The customer was looking at adding a RV plug in to his house. I over heard them saying it was 240V they were going to need to wire this up. I stopped them and explained that it was not 240AC connection they needed, but they looked at me like I was stupid.

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The receptacle used at campgrounds is actually a NEMA 14-50R, 240V receptacle. It's exactly the same, with the same wiring as the receptacle that my 50 amp oven plugs into at home. It's just that our RVs use the 2 hot wires differently than the oven.

The place people usually get into trouble with home receptacles is the wiring for 30 amp receptacles. It's pretty common for people, including electricians, to install a NEMA TT-30R (travel trailer 30 amp) receptacle, but wire it to provide 240V as they would wire a 30 amp NEMA 10-30R receptacle for a home dryer. You can read about this here.

sengli said:

I was at at menards the other day, in the electrical area. The customer was looking at adding a RV plug in to his house. I over heard them saying it was 240V they were going to need to wire this up. I stopped them and explained that it was not 240AC connection they needed, but they looked at me like I was stupid.

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For a more in depth explanation of the RV 50 amp electrical service, see: http://www.myrv.us/electric/index.htm and click on "50-Amp Service" on the top left.