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jomondnv · 01-04-2015, 09:09 AM

I have had two plugs melt on me while plugged in to a 30 amp post. This has happened over period of 8 months. Both campground might be a little suspect on the electrical side looking back. What is this caused by? Im going to purchase a surge protector before my next outing. Should I replace the plug, or buy a whole new cord. Also is there any difference to look for in purchasing a new cord.
Thanx for any help.

bwoodtx · 01-04-2015, 09:13 AM

Generally this is caused by a loose connection either on your side or the park's side.

Low voltage can also cause this. I would recommend that you get a GOOD plug-in voltage tester to leave plugged into a visible outlet. Don't by an analog one-they are cheap and inaccurate.

tjdonahoe · 01-04-2015, 09:13 AM

My 04 did the same thing before I owned it,with the air on and the electric water heater was a bit much as it would trip the breaker,so we jut run one at a time, no problem..

Ag&Au · 01-04-2015, 09:19 AM

Quote:

Originally Posted by jomondnv

I have had two plugs melt on me while plugged in to a 30 amp post. This has happened over period of 8 months. Both campground might be a little suspect on the electrical side looking back. What is this caused by? Im going to purchase a surge protector before my next outing. Should I replace the plug, or buy a whole new cord. Also is there any difference to look for in purchasing a new cord.
Thanx for any help.

There are a few things that could cause this. Melting is caused by heat and heat is caused by current flowing through resistance. So either there is too much resistance or too much current or both. There are so many variables involved it this, I would strongly suggest you have a certified RV tech check this out for you. I have been involved with electricity since I first got my ham license at the age of 15. I also have 2 years of electrical engineering education. However I would not attempt to try to guide you remotely through the various things that could cause this, because more damage could be done in the process.

Ken

terryV · 01-04-2015, 09:22 AM

I have never had the main power cord plug (male end) heat up or melt, but I have had the female plug of the second cord in line (two cords for longer distance) get hot and melt.

I always figured it was a bad connection. I noticed that when I made sure the cords were seated all the way in, and good and tight, there was no problem.

It could be a faulty plug in the electrical box, or perhaps you weren't fully plugged in.

Foiled Again · 01-04-2015, 09:34 AM

I second what Ag & Au said.

One very simple thing - there are a lot more RV's that use 30 amp than that use 50 amp. The outlet itself wears out. I've sometimes plugged in to an outlet that is so worn the plug wants to fall back out. This is an indicator of a poor connection which adds significantly to the resistance and generates HEAT. If you recall the times that you melted a plug - was the outlet loose feeling?

SIMPLE SOLUTION - If the 30 amp plug feels loose, use a "dogbone" 50amp to 30 amp adaptor. It's about a foot long, normally yellow, it plugs into the 50 amp outlet and allows you to plug in your 30 amp cord into the other end. You can find them at most camping stores. (I looked for one at WalMart but just wasn't impressed - poor quality).

Happy trails, Paula

J. Morgan · 01-04-2015, 10:56 AM

It is almost certainly due to a poor connection at the prongs, combined with heavy current use.

1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

Ag&Au · 01-04-2015, 11:20 AM

Quote:

Originally Posted by J. Morgan

It is almost certainly due to a poor connection at the prongs, combined with heavy current use.

1/2 Ton 4WD Truck, 72 Sovereign Hensley Arrow

I agree that those are the most likely problems. However the real question is: What is causing either?

I for one, am not willing to long distance guide someone possibly inexperienced through trouble shooting the problem with definitely lethal voltages along with high current capability present. There are many things in an RV that can be safely worked with when you are not previously trained. However AC line voltage and LP gas are two that should never be attempted unless you are thoroughly knowledgeable about what you are doing and what the dangers are.

My guideline for both is:
If you have to come to an internet forum to ask about them, then you shouldn't be messing with them. Spring for the bucks to have someone who knows what they're doing fix them.

That's my story and I'm sticking to it.

Ken

greenflag · 01-04-2015, 11:40 AM

I had the same thing happen to my 2007 International. The problem was in the pedastel. I purchased a new 30 amp cord and surge protector. I like the idea of the dog bone and using the 50 amp plug. There are questionable power boxes out there. I think we all have plugged into one or two in the past.

SteveSueMac · 01-04-2015, 11:47 AM

Some very good advice here. I had the same problem last year and it was basically due to a looser connection at the pedestal than needed. If I don't get a solid, tight, very flat/flush fit on the pedestal, I have a long Velcro strap (and a tennis ball against the back of my plug if needed) I use to snug it there.

While it didn't fully melt (to be useless) the pins did have some oxidation on them. If you have that, it's important to sand/file that off to improve your connection.

Good luck!

dwightdi · 01-04-2015, 11:56 AM

You should check to make sure that your male prongs are free of corrosion. You can use a wire brush to clean them. The pedestal female receptacles frequently overheat and lose their ability to contact the prongs tightly. This leads to more resistance and problems. If the connection feels loose, do not use it. The 50 amp dogbone is a quick trick to avoid having to repark at a new site.

Foiled Again · 01-04-2015, 12:09 PM

Outdoor plugs are going to wear out a bit faster than indoor ones - Here by the ocean even the fog has some salt in it. Anyone who has ever gone to a hardware store or electrical supply house can find that there are "good/better/best" grades of outlets. Some campgrounds use the cheapest stuff to wire their pedestals and they don't/won't rewire them even when the outlet itself is cracked or too worn to hold the plug in the socket. Strapping the plug in doesn't work, because internally the plug isn't pressing tightly on each prong.

If I get a bad 30 amp, I will always call the campground manager and ask to be moved to another space, OR have someone come out and replace the 30 amp connection itself. I've gotten some flack back, but I am paying for 30 amp electrical, not a primitive site - and so all I'm asking is for the management to supply what I've already paid for. I'll use the dogbone for a night, but next day have the pedestal fixed. Every camper who uses the site will have the same problem. If you're polite about it, you rarely have problems. Once in Ohio an aging owner in an aging campground got nasty when I complained about power problems AND the sewage backing up - and threatened to call his buddy the local sheriff. I had a family situation so I toughed it out. After I left I called the local health inspector. That campground closed. Apparently the septic system had ceased to function quite a few years before... and the owner had diverted the raw sewage into an abandoned quarry. The cost to upgrade the campground and clean up the quarry was apparently prohibitive. (In 10 years or so, the quarry will contain "fertilizer").

Paula

SteveSueMac · 01-04-2015, 12:12 PM

Thanks, Paula - I hadn't thought about the internal wear of the female receptacle itself and the potential non-solution of the Velcro strap! Good to know - and as usual, the rest of your advice is just spot on. Thanks! :-)

Wingeezer · 01-04-2015, 12:23 PM

Haven't had this problem myself -yet - but as usual, good advice given already in this thread.

My guess would lean towards a bad pedestal socket and/or corroded prongs on the plug causing unwanted resistance and overheating.

Mental note made for next time we take our trailer out to make sure our plug prongs are bright and also that I still have a 50-30 adapter stored in the trailer just in case!

Brian.

Schu · 01-04-2015, 12:36 PM

Are you using an extension cord to reach your hook-up?

Msmoto · 01-04-2015, 12:38 PM

When voltage is low, the amperage must go up and this creates heat build up.... or so i am told.

I was plugged into a 50 Amp circuit which had less than 104v on one leg, about 104v on the other side. It created problems for me in my moho, eating a transformer in the inverter, about a $2800 part, installed. Fortunately, I was able to have it repaired by a factory service center, cost about $600.

Now, I was able to see the low voltage on my meters in the moho, but failed to understand the significance of this. Should have moved to a different location in the RV Park.

Sodbust · 01-04-2015, 01:22 PM

All it takes is near a full amp load with a little chunk of sand stuck between the socket blades.. 19 times out of 20 when I have seen this happen it was due to careless handling of the cord plug ends and getting dirt and or sand in the plug while connecting.. Don't just drag the cord ends on in the dirt while handling the power lines..

I have even seen a build up of corrosion heat up a plug and a little steel wool and elect. cleaner fixed the problem.. ( if its the male plug) Sodbust

idroba · 01-04-2015, 01:35 PM

There are two parts to the connection to a 30 amp outlet, the male plug on the trailer end, and the female socket on the campground end (duh). Either or both can be a problem and either or both can cause damage to the other part.

If the campground end is loose, cracked week contacts etc. it will cause heating when a heavy load is applied. The trailer plug may become overheated and melt, when it was good to begin with. If the trailer plug was poor to begin with, loose pins, corroded blades, it can be the cause of the overheating further damaging it and the campground socket it is plugged into.

Cleaning blades on the trailer plug may help but in general once the socket it is plugged into is damaged or worn nothing but a new one will fix the real root of the problem. If the plug wants to fall out of the socket it will never make good enough connection to transfer the full 30 amps without further heating and damage, even with a bungie cord holding it place.

Once the contacts in the outlet have been overheated they usually lose their spring and can no longer grip the blades of the trailer plug tight enough for full power transfer.

So, usually the problem is on the campground socket side of the ownership, due to the heavy use and number of times the socket is used in a year. But it is also possible that the plug from a trailer can cause early failure of the socket, so the RV owner is not always blameless (well, SOB owners are the problem, never an Airstream owner (giggle)...).

If you are using your RV's electrical system hard (AC or heaters on, water heater etc) go out and feel the plug where it goes into the socket. It should never feel more than slightly warmer than the surrounding objects and air. A 30 amp plug/socket system is designed and built to have virtually no heating when fully loaded. If it does, there is a problem brewing.

I recently had a washer-dryer problem in my home. I put my hand on the dryer plug/socket and it was warmer than the air and walls surrounding it. It all felt tight. But I went out and got a new outlet anyway. When I pulled it out for replacement, one of the terminals on the old socket did not have any spring left so it did not grip the plug blade very well. That was the cause of the heating. It had not damaged the dryer cord or plug yet, but there was no way to re temper the brass in the terminal so it would ever grip properly. It had to be replaced. Had it gone on, the dryer plug itself would have become hot enough to melt where the blade went into the molded part of the cord set. The same thing can happen in an RV situation, plug or socket.

**GCinSC2** · 01-04-2015, 02:05 PM

I've lost two plug ends. They replaced the receptacle one time and the screw for the wire was all corroded but I think the real cause is hot connections and disconnections. If the power was always off when you connect or disconnect then no sparking and surface erosion leading to higher resistance connections and heat. So I try to always connect with the pedestal circuit breaker OFF.

I also check the plug end once in a while for heat. Feels hot, better check.

dominicjohn · 01-06-2015, 02:22 PM

We had a 30A Cable melt down a couple weeks ago. It was the end of the cord that attaches to the trailer and twists on. The back side of the receptacle that it attaches to on the trailer actually melted and the end of the cord attached to it was molten. Could it have been the campground post that caused this at the far end of the cord? I was thinking that we had a short on the back side of the recepacle on the trailer.