So after the winter, I pulled up and moved. I was using the 50A socket with the 50-30 adapter. One of my connections was burnt up and the plastic was melted.The flat prong was black.The part that plugs into the pedestal was ok. That part was also shielded from weather.The 50-30 adapter part is about 12" long. The 50 side was ok as mentioned above. The problem was on the 30 side, which was in the weather. The black wire terminal was the one that was burnt up.Anybody have insight on causes here?

Pulling too much power through corroded connections. This can happen to me when I run the a/c and my water heater is on electric. You have to assess what are your big draws and try not to run them at the same time.

You said you were plugged into a 50amp pedestal and adapted down to a 30amp cord. Common sense tells me the 30amp cord is only capable of safely carrying 30amps. Anytime you approach 30amps, that cord will begin to heat. The heat causes rapid oxidation. The oxidation creates an increased resistance to the flow of current. The increased resistance results in more heat. From that point on it's like a dog chasing its tail. The more heat, the more oxidation, the more oxidation the more resistance and therefore even more and more heat - your plastic plug melts or worse yet catches fire. During all this you've never come close to the 50amp load required to trip the breaker and open the circuit so the process continues until somehow power is interrupted.You can minimize some of that oxidation by using a di-electric grease" available from Camco at RV supply stores or from Permatex at auto parts stores. I've been using it for years with great results and haven't burned up an plugs - but then I try not to overload them either.

Just replace the burnt parts A poor connection caused excessive heat. Jerry Parr

Service Unavailable Duplicate Post

If you just replace the burnt ends and make no other changes, expect the same results. You can't put 50amps through a 30amp cord without melting something!

The black wire on my plug is burnt up... | Good Sam Community

ol_Bombero-JC
Explorer
Oct 30, 2021
myredracer wrote:
cavie wrote:
Ease up guys. Let's get back to electric for newbies 101. Save the electric engineering 2.0 for another forum. :):)
Agreed! Been retired too long and this stuff gives me a headache now. :(

"BUMP" for an old thread!
(which is linked to a newer one).

To solve the loose 30Amp plug at campground pedestals - use the 50AMP
(there usually is one) - with a 30 to 50 adapter...:W

Never found a loose 50amp, but "sloppy" 30s are common!...:(

Do your fellow campers a favor - politely inform the campground of the
"situation" at the pedestal on site #.....

AND -

you will be posting the "problem" on site #.... at campground
(name) on all the forums you visit.
May or may not expedite repairs - but can't hurt - it's also a "heads up" for the next visitor!...:C

~
time2roll
Nomad
May 09, 2019
myredracer wrote:
But the 80% rule doesn't apply to plug-in loads. That would be like saying you can't plug a 1500 watt portable heater into a 15 amp receptacle because it draws more than 80% of 15 amps (12.5 amps). DW has a blow dryer that is rated 1875 watts (15.6 amps) and same thing there.

1500 / 125 = 12 amps
15 amp outlet x 80% = 12 amps
Coincidence? Heater possibly runs continuous.

1875 / 125 = 15 amps
Hair drier is not considered a continuous load.

Of course most voltage will be 115 to 120 at the connector so these items will draw a bit less.
myredracer
Explorer II
May 09, 2019
.
myredracer
Explorer II
May 09, 2019
.
myredracer
Explorer II
May 09, 2019
cavie wrote:
Ease up guys. Let's get back to electric for newbies 101. Save the electric engineering 2.0 for another forum. :):)
Agreed! Been retired too long and this stuff gives me a headache now. :(
cavie
Explorer
May 09, 2019
Ease up guys. Let's get back to electric for newbies 101. Save the electric engineering 2.0 for another forum. :):)
cavie
Explorer
May 09, 2019
myredracer wrote:
CA Traveler wrote:
Keeping it simple just follow the NEC rule of 80% continuous load. I doubt any RV pedestal or RV panel is rated for 100% continuous load.

In this non simple article there is a lot more information. CLICK
I understand what you are trying to say. But the 80% rule doesn't apply to plug-in loads. That would be like saying you can't plug a 1500 watt portable heater into a 15 amp receptacle because it draws more than 80% of 15 amps (12.5 amps). DW has a blow dryer that is rated 1875 watts (15.6 amps) and same thing there. (Interestingly, like portable heaters also, only has a 16 gauge cord.) There's other examples where plug-in loads exceeds 80% of a breaker on a circuit being plugged into. You can also have multiple receptacles on a circuit and easily exceed the 80% rule.

If you can't or shouldn't exceed 24 amps on a 30 amp pedestal, why does the NEC require a 30 amp load allowance per pedestal? Why doesn't a pedestal say you shouldn't exceed 24 amps or an RV have a sticker on the power inlet saying the same? There is simply nothing in art. 551 that requires an RV to be considered as a continuous load.

RV pedestals have to meet UL standard 231 and molded case breakers, UL 489. I think you'll find that you have to look at a UL standard for a piece of equipment as whole, not individual components in it. I haven't looked for a copy of UL 231 and don't know what the details are in it.

A bit of a head scratcher question and no immediate answers pop up on google. IMHO, it boils down to RV and RV park rules in art. 551 and the fact that RVs are plug-in loads, not hardwired like in a building.
myredracer
Explorer II
May 09, 2019
CA Traveler wrote:
Keeping it simple just follow the NEC rule of 80% continuous load. I doubt any RV pedestal or RV panel is rated for 100% continuous load.

In this non simple article there is a lot more information. CLICK
I understand what you are trying to say. But the 80% rule doesn't apply to plug-in loads. That would be like saying you can't plug a 1500 watt portable heater into a 15 amp receptacle because it draws more than 80% of 15 amps (12.5 amps). DW has a blow dryer that is rated 1875 watts (15.6 amps) and same thing there. (Interestingly, like portable heaters also, only has a 16 gauge cord.) There's other examples where plug-in loads exceeds 80% of a breaker on a circuit being plugged into. You can also have multiple receptacles on a circuit and easily exceed the 80% rule.

If you can't or shouldn't exceed 24 amps on a 30 amp pedestal, why does the NEC require a 30 amp load allowance per pedestal? Why doesn't a pedestal say you shouldn't exceed 24 amps or an RV have a sticker on the power inlet saying the same? There is simply nothing in art. 551 that requires an RV to be considered as a continuous load.

RV pedestals have to meet UL standard 231 and molded case breakers, UL 489. I think you'll find that you have to look at a UL standard for a piece of equipment as an assembly, not individual components in it. I haven't looked for a copy of UL 231 and don't know what the details are in it.

Circuit breakers are designed to operate at 100% but code typically doesn't allow connected loads to exceed 80% of their rating for loads considered continuous. Here's one article that says "CBs and other OCPDs can be sized at 100% of their rating for any NONCONTINUOUS load applications." Clifford Power (Note that "100% rated" breakers are not the same as standard breakers.)

A bit of a head scratcher question and no immediate answers pop up on google. IMHO, it boils down to RV and RV park rules in art. 551 and the fact that RVs are plug-in loads, not hardwired like in a building.
myredracer
Explorer II
May 09, 2019
CA Traveler wrote:
Keeping it simple just follow the NEC rule of 80% continuous load. I doubt any RV pedestal or RV panel is rated for 100% continuous load.

In this non simple article there is a lot more information. CLICK
I understand what you are trying to say. But the 80% rule doesn't apply to plug-in loads. That would be like saying you can't plug a 1500 watt portable heater into a 15 amp receptacle because it draws more than 80% of 15 amps (12.5 amps). DW has a blow dryer that is rated 1875 watts (15.6 amps) and same thing there. (Interestingly, like portable heaters also, only has a 16 gauge cord.) There's other examples where plug-in loads exceeds 80% of a breaker on a circuit being plugged into. You can also have multiple receptacles on a circuit and easily exceed the 80% rule.

If you can't or shouldn't exceed 24 amps on a 30 amp pedestal, why does the NEC require a 30 amp load allowance per pedestal? Why doesn't a pedestal say you shouldn't exceed 24 amps or an RV have a sticker on the power inlet saying the same? There is simply nothing in art. 551 that requires an RV to be considered as a continuous load.

RV pedestals have to meet UL standard 231 and molded case breakers, UL 489. I think you'll find that you have to look at a UL standard for a piece of equipment as whole, not individual components in it. I haven't looked for a copy of UL 231 and don't know what the details are in it.

A bit of a head scratcher question and no immediate answers pop up on google. IMHO, it boils down to RV and RV park rules in art. 551 and the fact that RVs are plug-in loads, not hardwired like in a building.
Lynnmor
Explorer
May 09, 2019
DFord wrote:
My experience over the many years I've been RVing has taught me drawing over 25 amps on a sustained basis (like when the a/c is trying to keep up during the heat of the day or space heaters on a cool night) will always ruin a cord plug. The connection points just aren't good enough to carry that load continuously. As proof, I submit the many 30 amp sockets you'll find in every park I've ever stayed at. They don't get burned up that way because they're carrying more than 30 amps because the breaker prevents that from happening.

I think you will find that most plugs are smoked by outlets that have been abused by those that yank the plug while there is a load on it. I always plug in and out a number of times in the hope of scraping off some of the burned surface.

An unseen poor wire to blade connection inside the plug might be the problem that the OP experienced. Just another thing to consider when using cheap RV electrical parts.

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The black wire on my plug is burnt up...

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