Newbie question about 30 amp service

[Rhino33]

Question - when I have our 1980 31' connected to our garage for shore power, the inverter is charging our single battery and all lights and fantastic fans are operational. I will need to recheck, but I think a few of our outlets are not operational. If we try to turn on the AC fan, it works, but to turn on the AC to cool, it blows the circuit. If we try to turn on the original Dometic gas/electric fridge, it blows the circuit.
How can we check our fridge to see if it works on AC power? (since we are more concerned with the fridge working than the AC)

[Starstream]

What a great thread

I was advised to put in a separate 30Amp (TT-30R) receptacle and separate 30Amp circuit breaker at the house. Not to use a dog bone or any type of adaptor to plug into the 30Amp 240 dryer outlet or the 50Amp 240 outlet I have set up for the woodworking/power tools. Because it can over heat the 30Amp, 8 gauge, 3 wire, 120 line used as the main electrical line to the trailer. Going to any 240 outlet could over heat the 120 wire at either connection point (breaker box inside the trailer or house), causing a fire.

The way it was explained to me was, I could plug into a 30Amp outlet as long as that outlet is a single pole breaker. Could also go down from a 30Amp single pole to a 15Amp single pole but would have to sacrifice the use of the A/C. But never plug into a 240 outlet even with an adaptor.

They also said the same thing applies to hooking up to a generator or at any camp site. Hooking up to a 240 outlet, double pole breaker, may work sometimes but all it takes is once for it not to work to cause a major problem.

But I am by no means any kind of expert. I can only go by what information was told and explained to me. If I am wrong, besides being a little miffed by the extra expense of the new breaker, wire run and receptacle. Okay it is just that, the new in ground line, conduit, receptacle and work done was a rather expensive thing and those funds could have gone into the renovation project instead. I guess I'm going to feel rather stupid if all I really needed was a 10-30 dollar adaptor.

[xrvr]

Never use a 240 volt anything. No one told you too. You need a thirty amp 120 volt outlet. Jim

[DaveFL]

Originally Posted by Starstream

What a great thread


The way it was explained to me was, I could plug into a 30Amp outlet as long as that outlet is a single pole breaker. Could also go down from a 30Amp single pole to a 15Amp single pole but would have to sacrifice the use of the A/C. But never plug into a 240 outlet even with an adaptor.

But I am by no means any kind of expert.

Not rocket science, just electric that can kill you, don't need to be an expert, just carefull and be able to read a meter.
The adapter 50 to 30 they are talking about may look like a 50 amp plug but one of the positive legs doesn't get a connection. Just because you are plugging in 4 prongs only 3 come out of the adapter. Put a multimeter on the adapter and check before you plug it in, if someone wired it wrong you could have 240 v.

In all of these possible problems nobody mentioned another test item, a thermometer, IR thermometers are getting cheap enough to keep track of electric overheat, tires, wheel and motor temp. never travel without one. Saved the day when diagnosing a brake problem.

[DaveFL]

Originally Posted by TG Twinkie

The 50 amp service provides 50 amps of current to each leg. Since you are using 1 leg, there is still 50 amp capacity. Even when you plug in the adaptor. It doesn't know the difference between your rig and one that has 50amp requirement.
You should have a main 30 amp breaker in your coach. Which will trip if overloaded. The only part that is not protected is the shore power cable. If it were damaged to the point of causing the camp sight breaker to trip. It would not matter if it were 30 or 50 amp.

Absolutely correct, I would like to add that the available 50 amps in 30 amp capacity cord that has a faulty connection could overheat even with the 30amp breaker in place at the camper. One reason why I switched over to 50 amp wire and transfer switch then put in 50amp breaker in the rv box and a separate 20 amp breaker for the second a/c that doesn't go to the breaker box in rv.

[Starstream]

Originally Posted by zigzagguzzi

Never use a 240 volt anything. No one told you too. You need a thirty amp 120 volt outlet. Jim

Thanks Jim, that makes me feel better about putting in a separate set up at the house.

[Starstream]

Originally Posted by DaveFL

Not rocket science, just electric that can kill you, don't need to be an expert, just carefull and be able to read a meter.
The adapter 50 to 30 they are talking about may look like a 50 amp plug but one of the positive legs doesn't get a connection. Just because you are plugging in 4 prongs only 3 come out of the adapter. Put a multimeter on the adapter and check before you plug it in, if someone wired it wrong you could have 240 v.

Thank you.

Since I am new to all this, I want to make sure I don't make a huge mistake that could jeopardize anyone's safety.

[mimiandrews]

Check out RV Electrical Systems by Bill and Jan Moeller. It starts out with a simple explanation of basic electricity and then goes into details about how things work in an RV.