Electrical question

[kardar2]

Hello,
off the bat this is my first rv (5th wheel). It is a 88 automate. When I Have my trailer plugged into shore power I had my A/C running on hight for about 4 hours and it blew the A/C breaker in the trailer. The plug to was really hot. Is this normal? The breaker in the trailer might be starting to get weak. The wife and I are hoping to buy a new trailer down the road. Are the new trailers more efficient on drawing power these,days? Thanks

[garry1p]

One thing to consider the lower the voltage to the AC (usually a bad connection at the post or your plug is corroded)causes the current to increase once the voltage gets below 108VAC you can very well damage the AC.

It is a good idea to have a voltage meter plugged into one of your 120V outlets at all times so you can monitor the incoming voltage. Anytime below 108 or above 132 it is time to shut things down and find out what is going on.

[wa8yxm]

Plug can get hot from one of two things..
Most common: High resistance and high current
Least: Sunlight shining on it.

One of the things I always do when I pull out the 30 amp cord is clean the blades as they tarnish, resistance builds and it melts.. THEORY has it you should be able to pull 30 amps. Pull more and you get the click of darkness (Breaker trips) but it appears 30 amp plus are not able to handle 30 amps well.

Now.. You said it was tripping the 20 amp branch breaker as well.. True story

My Front A/C was doing that back about Mar/April.. After I verified it waS pulling 21 amps at the point where the breaker broke (tripped) I went topside to see if I could figure out why (had an idea,, I studied engineering after all) pulled top cover, Pulled condenser cover.. Blew crud out with compressed air and soft brush.. Cleaned the rest of it while I was up there.... Replaced covers.. 30 Confirmed a nice 13-14 amps on the meter (it only does units, not tenths and it said 13) for quite some time after I got back inside.. unit is runnign fine since.. To this very minute.

[kardar2]

Thanks for the help

[Joe417]

Kardar2,

A weak or dirty receptacle can cause the plug to heat and cause a drop in voltage. Compare the voltage at the campground receptacle to voltage inside the camper at a receptacle. That sounds like what you are describing.

My rule of thumb, if the interior receptacle is less than 110V with the air condition running it may cause problems. (Measure with AC running)

If the air conditioner evaporator and/or condenser get dirty that can also increase the current drawn. I wash my AC every couple of years.

Every RV AC problem I've ever had was due to a dirty unit. (Sometimes dirt daubers)

[MEXICOWANDERER]

Saw a nifty toroid sender for AC the other day while web surfing. Clam shell design. No need to disconnect wire. Standard mv ouput for many AC ammeters

[GMandJM]

power source = 30a service that you tester to make sure really IS giving you 30amps?

[kardar2]

No extension cords or adapters. Plugged directly into power source. It is in a camp ground like setting. I will check the plug thanks

[Lynnmor]

It is high resistance where the heat is, nothing more, nothing less. You need to determine if it's your plug or the outlet. Most often the outlets are ruined by those folks plugging and unplugging without turning off the breaker.

[Happytraveler]

You have to have 30 amps source or more to run the air conditioner. If not things get hot and will pop the breaker. My personal experience from home, LOL. Otherwise get your 5th wheel checked out.

[RoyB]

Was this running 120VAC from your house with an extension cord and a RV30A-15A adapter etc....

Roy Ken

[Artum_Snowbird]

Any time you get a hot connection it comes from that particular part having a high resistance connection compared to the rest of the circuit.

So, the cause can be in your part, or in the part that you are plugged in to. Among the possibilities are: 1)the wires in your plug are not connecting well to the actual connecting spades in your plug. 2) the spades on your plug have been overheated before, and have lost their conductivity.

On the other side, in the receptacle, the grippers that grip your spades may have overheated, and so it is like a loose connection.. or the wires to the receptacle may be loose.

Both of these conditions may be present at the same time even. An electrician with a couple of meters can determine the actual problem.

[2oldman]

It's normal if you're drawing too much power. Other things can use lots of power, like your converter and water heater. Extension cords don't help either. And your plug must have good solid clean connections.

Is this in a CG? Many CG power systems are inadequate to handle lots of folks running air at the same time. And their pedestal connections are old and corroded.