Community Forums

cubano222 · 07-06-2011, 03:33 PM

Man, I was cleaning the inside of the MH last weekend & thought, hey its hot in here, so I turned on the roof air. It came on for about a minute then stopped. There was no power in the MH. I figured it had thrown a breaker in my garage but all the breakers were ok. I then checked the breakers in the MH & they were ok. I thought, well let me check the cord. The 30 amp plug and the pigtale going to the extention cord were on fire & sparking. I unplugged the extention cord & blew out the fire. Fried the whole thing. Camping World was open on the 4th so I took my burned up pieces & bought a new 30 amp plug & pigtale. The guy at Camping World asked me, you tried to run your A/C plugged into 120 didn't you. I said yea, it was hot. He said, you would be surprised how many of these we sell cause you are not supposed to do that. He said the pig tale going to 120 source is ONLY to run your fridge & keep your batteries charged. Run your A/C through your generator or plug into 30 amp at a campground. Never knew that. 60 years old & still learning. Glad I didn't set the whole MH on fire.

wa8yxm · 07-06-2011, 04:03 PM

Cubano.. I'm a certified electronics technician, ran my A/C for many hours (usually only an hour at a time though) on 20 amps, (Kind of a long story, it's a 30 amp outlet, but 20 amp wire and breaker) no problems such as you cite.

It makes no sense.. The only thing that does make sense is perhaps you had a bad socket on your adapter. That could do it. Or the cord was old and about to fail.

4Knights · 07-06-2011, 04:13 PM

Was your extension cord a 15 amp cord? I use a 30 amp extension cord plugged into the garage outlet. Now my outlet has 15 amps to the top and 15 amps to the bottom from different breakers in the garage so no issues at home but when at relatives house we use the same cord and only get 15 amps due to their wiring from breaker panel to outlet. You can use a regular cord but the draw will be more than the cord can handle and overheat with time. May or may not trip house breaker.
If it's your house go to local hardware store get a 30 amp breaker, correct gauge wiring and and external RV or Generator receptacle, you can pull the wire yourself and just have an electrician do the final connections in the box and the outlet to stay within code. (don't forget to put the metal tabs over the studs to protect the wire from nails/screws)

cubano222 · 07-07-2011, 07:57 AM

It did look like the previous owner had replaced the 30 amp plug at some point. I have run the A/C several times before with no problems. I use a heavy duty ext. cord & it was not hot to the touch anywhere. The only thing burning was the 30 amp plug & pig tale plug. The 30 amp plug has sparked before so it was probably going bad. I'm going to try it again & if I burn out another plug, cheap enough to replace. Thanks for your suggestions.
Jerry

Senior Chief · 07-07-2011, 11:48 AM

I agree, the "expert" at Camping World is all wet. Your A/C is designed to run perfectly well on 120V. Possibly he meant 15 amp, but even there he's not correct.

I agree that the issue here is a bad plug/wire/connection; any of these will cause heat which can lead to fire. If a previous owner rewired anything in your house cord or adapter, that's the likely culprit.

A clean, tight connection, even to a 15a breaker should be fine, with a single AC.

JiminJersey · 07-07-2011, 11:58 AM

+1 to Sr. Chief about the CW "expert" - you should be able to run the AC all day long on a house circuit, IF there are no other major draws on it, and IF your cord from the outlet to the pig-tail is adequate. I bet the CW guy gets a lot of people who've blown out or melted pig-tails because they used cheap extension cords from the house to the RV.

TXiceman · 07-07-2011, 05:34 PM

A 15 amp house circuit is marginal, a 20 amp should run one A/C with no problem. It sounds like you had a 15 amp and long extension cord which you overloaded. Bet a 20 amp rated cord and keep it as short as possible.

I have run a many an RV A/C with a 20 amp circuit in the garage.

Oh, I think you have to have the intelligence of a bag of rocks to work at CW.

Ken

ahicks · 07-07-2011, 07:57 PM

If you have a cruddy connection (dirt/grease/corrosion/whatever) on a 15, 20, or 30 amp connection, it can get hotter than all get out with any serious current draw on it - no matter the wire size. The "plug adapter" used to convert the 30 amp connection on you power cord to a residential connection are famous for melting down...

cubano222 · 07-11-2011, 10:13 AM

I do have a 20 amp breaker that my extension cord is plugged into. I ran the A/C for several hours during a very hot day here in TN yesterday & had no problem. The new 30 amp plug & adapter pig tale didn't even get warm. Guess ya'll were right, the CW dude did not know what he was talking about. Thank you.
Jerry

BA-in-Mich · 07-15-2011, 06:14 PM

I have my MH hooked up to a 120v/20amp circuit through it's 50amp cable and I have ran my A/C for hours on end and no problems. The cord I use is a 12 gauge 50'.

high5 · 07-15-2011, 09:28 PM

Quote:

Originally Posted by BA-in-Mich

I have my MH hooked up to a 120v/20amp circuit through it's 50amp cable and I have ran my A/C for hours on end and no problems. The cord I use is a 12 gauge 50'.

I do the exactly the same thing also without incident. I do check the plugs/adapters every so often for overheating. Maybe some adapters are constructed better than others. It only takes about a 2% volt drop across a poor connection to cause big problems when your drawing heavy currents. Also, a reduction of starting current (typically 25A) could eventually damage the A/C.

wa8yxm · 07-16-2011, 10:44 AM

IN another thread someone spoke of plugging into 30 amps at the RV park.. Well when he went to unplug he had to call park maintenance cause the plug had MELTED to the outlet. They shut off the breaker, hacksawed his power cord, installed a new plug and then, just for the heck of it, took the original apart.

Turns out the "Pins" (Blades on the plug) were CRIMPED to the wires in the cord, not welded, not soldered, but crimped and the technician/machine that crimped them only caught about half the wires in the plug, So under heavy load, the half-connecting rapdily overheated and .. Well you already know the rest.

yes, qualiity control is about half what it needs to be in some places. Less in others.

True story (I WAS THERE) person on the site in front of me pulls in in a brand new 5er. Plugs in the power cord and NO POWER (50 amp, Marine co connector to coach)

I grabbed my meters and we pulled the Marine Co from the coach, intending to do volt meter measurements to see if the cord was bad.

The connector fell off

They had not tightened the inernal screws,, At all.

vman60 · 07-16-2011, 06:40 PM

All I do is take the 30amp main powercord and plug it into a 30amp exstenson right into the outside plug into the house and its all good from there. But was told you can't run a/c microwave and all at same time. Also when I bought the coach from the original owner he was telling me you can't run both a/c's at same time without being pluged in and generator running. I have had the generator running and both a/c's going at same time. Now its my understanding if you have your generator running and you are plugged in to a 30amp service that 1 power source is cancelled out such as the main plug unto a 30 amp service. 1 or the other is supplying power to the coach and not both which makes sense beings there is only 1 control panel (circut box).

high5 · 07-17-2011, 09:36 AM

I've done an electrical load inventory in the past and if I remember correctly, the worst case values for a rooftop 13,500 BTU A/C are: 1700W / 15A running and 3000W / 26A starting. But, a newer A/C unit usually runs at 1300W / 11A and starts with 2700W / 23A. I don't remember the duration of the start cycle, but it's short (for a correctly functioning unit) and both 15A and 20A breakers would handle it. Although, running 100% current for long periods through a household breaker will most likely trip the circuit eventually, depending on the type of breaker. My rig has a single A/C unit and a 4kW Onan so I have plenty of power. But I've been told by reasonable sources that some modern two unit systems have circuitry to prohibit simultaneous starting. Bottom line is 11A (75%) load on a 15A household circuit will run all day (with good connections). There are contact cleaners that chemically improve the conductivity of the contact's base metal. They're expensive but I think they're worth the investment. I personally don't use anything less than 12ga cords or a 10ga if you can afford it. But little can be done to compensate for poorly constructed equipment, IMHO.