30 amp plug melting

[Roadhappy]

Went to Concan, TX this last weekend and had a really relaxing time tubing on the Frio River.  After 2 nights we were packing up and my DH called me over to look at our 30 amp plug.  It looked like it was just starting to melt and you could really smell it. 

We had just ordered a progressive surge protector but had not received it when we left for our trip. ( It was waiting at our neighbors house when we returned home).  We did not try the TV but everything else worked all weekend. 

First question is If we would have had a surge protector on the trailer, would the plug still have started to melt?

Next question:  Do we need to buy a new cord  or can the plug be replaced?

and lastly: Did we cause this by running the microwave and the AC at the same time?

Thanks

 

[SeilerBird]

First question is If we would have had a surge protector on the trailer, would the plug still have started to melt?

Yep

Next question:  Do we need to buy a new cord  or can the plug be replaced?

Two questions actually. No and yes. Home Depot will have what you need.

and lastly: Did we cause this by running the microwave and the AC at the same time?

Yes and no. Yes running both can be the problem. No the breaker should have tripped first. The breaker sounds like it is defective.

 

[Bob Buchanan]

Do we need to buy a new cord  or can the plug be replaced?

The plug can be replaced. I had my 30A plug fry in Laughlin last month. Bought a new one from a local RV and Boat dealership in Bullhead City. HERE is one like mine on Amazon.

This one has a handle that is convenient, plus it really hugs the cord tightly to keep the wiring protected. Even with what I thought was Carpal Tunnel in my wrists was able to do the repair OK.  Some have written that the handle makes it hard to plug in on some posts, but I've yet to have that problem.

 

[captsteve]

Shore power cords and plugs do get old and need to be replaced on occasion. When you put a new plug on yours, make sure you get a TT-30 plug. Cut your wire back about a foot or so, when the plug got hot I'm sure it melted some wire insulation.

Steve

 

[Jeff]

We use a 30 amp plug on our 50 amp system and I usually have to replace it every 3-4 years because the 30 amp prongs start getting burned from bad connections and/or heavy loads.

 

[Just Lou]

Most likely the problem started from a worn and loose fitting campground receptacle.  They get lots of use and abuse.  The prongs on your plug payed the toll.

As stated by others, the plugs are easily replaced on your cord.

 

[Gary RV_Wizard]

It has been my experience that the 30A plugs start to melt if run at/near 30A for very long.  Technically the amp rating means it can handle up to 30A for a short period but that sustained use is only 80% of that, i.e. 24 amps. I'm not sure of the exact electrical code definition of "sustained", but it is something on the order of an hour, as opposed to minutes.

It's a good idea to replace them if they show signs of melt.

 

[bucks2]

Most likely the problem started from a worn and loose fitting campground receptacle.  They get lots of use and abuse.  The prongs on your plug payed the toll.

As stated by others, the plugs are easily replaced on your cord.

Good job Lou. I was reading down the replies deciding how I was going to word exactly what you said.

Corrosion/oxidation can be a problem with any kind of plug like that. On the boat which moors in salt water year around we clean the terminals regularly with contact cleaner to avoid overheating and fire. Many boats have burned because of poor contacts in the electrical plugs.

Paying attention to how the plug fits and making sure it is plugged all the way in helps, as does feeling the plug every now and again to judge how hot it's getting. You may think about reducing the load, or cleaning the plug and socket when you get one that makes too much heat.

Ken

 

[John From Detroit]

First question is If we would have had a surge protector on the trailer, would the plug still have started to melt?

Next question:  Do we need to buy a new cord  or can the plug be replaced?

and lastly: Did we cause this by running the microwave and the AC at the same time?

First answer: Perhaps. the melting plug is caused by a combination of 1 plus one of two things.

The one thing is high current (See answer 3) the two things are either a poor connection between plug and outlet -or- a poor connection within the plug.

Most likely the first (plug/outlet) it is posslble the new plug on the Power guard would have made a better connection and the new outlet on the power guard likewise would have made a better connection, assumign you got that kind,

It is more likely it would have made little difference.

Question 2: Yes you can replace just the plug, you may need to cut back as much as a foot on the cord (When you strip the wire for connecting if it's black, cut back more, if it's bright and shiny, GOOD.)

Running both A/C and microwave at the same time may have hastened it a bit, but I do not think it was the cause.  The cause was a poor connection.

Suggestion: inspect the plug every time you get ready to plug it in,  Bright and shiney good, Black bad,  Polish it up (nail file, sandpaper, emery cloth, DE-OX-IT Gold  all good ways to improve a connection)

 

[Roadhappy]

Thanks for all the information and explanations.  It's making us a little smarter.
We will be changing out the plug and will be checking it often when we camp.


Robin

 

[tvman44]

Melted 30 amp plugs are very common, mostly due to bad 30 amp receptacles, sometimes dirty 30 amp plugs.  Make sure your plug is clean and fits tightly in the receptacle, if not ask them to change the receptacle or move you to another site.

 

[Yellowboat]

I recently returned from a trip to BC Canada.  We stayed at one park where the power went off every afternoon.  On the third day some checked the power and found that those of us parked in three rows of the park were receving low voltage.  We were a group of four RV's traveling together.  We asked to be moved two rows over where there was no power problem.  They told us to move and when I unpluged my 30 amp chord I found that is was very hot and starting to melt.  The next day BC Power came to make repairs to the parks power grid.

I found it strange that my surge protector never cut my power.  Another member of our group said his surge protector did cut his power. 

Thanks for the posting.  We are leaving soon for an trip to the Washington coast and I had forgotten that I need to replace my 30 amp plug.

Safe travels.

JD

 

[Icemaker]

If it hasn't been mentioned somewhere....I also turn the pedestal breaker off so there is no power when I connect to it..then flip back on the breaker...any arcing is thus in the breaker and not across my plug when inserting it..

George

 

[Gary RV_Wizard]

I found it strange that my surge protector never cut my power.

Are you sure it has low voltage monitoring? Some models do not check voltage at all, and some others test it only once, when you plug in. If it has voltage monitoring, it should shut off somewhere between 102v and 106v. The exact number varies by brand.

 

[Foto-n-T]

As much as I love Texas, the high humidity can wreak havoc on electrical connections.  I cooked off a 30amp adaptor this last spring in the Corpus area and it was definitely a poor connection at the post that caused it.  We were camped at a KOA that still had a couple of rows that actually used 30amp glass fuses!!  Hopefully they will have upgraded by the time we return this winter.  If your shore post appears to have a loose fitting connection to your plug, say something to somebody in charge.  Even if they don't fix it you've documented the problem should melt down occur.

We're VERY frugal when running on 30amp simply because we learned the hard way that too much draw plus the A/C means the A/C will probably be the first casualty.

 

[Yellowboat]

Are you sure it has low voltage monitoring? Some models do not check voltage at all, and some others test it only once, when you plug in. If it has voltage monitoring, it should shut off somewhere between 102v and 106v. The exact number varies by brand.

I believe it does. 

Here is what Surge Guard says about my 30 amp Surge Guard:

"Surge Guard offers total protection with three individual safety circuits. Checks power pedestal for damaging mis-wire conditions and has warning indicator for reverse polarity, dangerous current on ground wire and pedestal mis-wire. Solid state (full mode) surge protection. Automatic over and under voltage protection. UL listed."

My guess is the low voltage was at or near the trigger point.  His surge protector tripped while mine was a little tighter.  Or perhaps I was getting slightly more voltage at my pedestal.

JD

 

[Carl L]

If it hasn't been mentioned somewhere....I also turn the pedestal breaker off so there is no power when I connect to it..then flip back on the breaker...any arcing is thus in the breaker and not across my plug when inserting it..

George

Very good practice.  Unlike normal household loads, like lamps, fans, etc.  RV shorepower connections are always made under load.  Shoving a plug into a recepticle will invariably cause arcing at the plug prongs.  The arcing will oxidize your plug prongs, increasing their resistance which leads to overheating. The connections should be made by a switch or breaker.  Turn the switch or breaker off when plugging in or out. 

 

 

[SeilerBird]

Very good practice.  Unlike normal household loads, like lamps, fans, etc.  RV shorepower connections are always made under load.  Shoving a plug into a recepticle will invariably cause arcing at the plug prongs.  The arcing will oxidize your plug prongs, increasing their resistance which leads to overheating. The connections should be made by a switch or breaker.  Turn the switch or breaker off when plugging in or out. 

Good advice. And don't forget to test the voltage before plugging in the first time. Test for the proper voltage and polarity.