Shore Power plug wiring mystery

[Ponysnake]

I have owned a 2003 Fleetwood Pace Arrow for 3 years. When I bought it, it's House Batteries(HBs)were dead, and it's Inverter was dead. I noticed that the Camco replacement plug on the shore power cord, had a bit of discoloration on it....but nothing too concerning.

I rewired and replaced the HBs, and installed a new inverter.  All worked well for the past three years, but I noticed progressively more damage, charring and melting around one of the Shore Power's lugs.  I decided to replace the plug. It is a 30AMP coach.

When I broke open the old plug, I found the White and Black wires were reversed, and the black wire was very fried. It had been arcing. The PO had miss-wired it.

I have correctly wired the new plug back up, but now I am concerned HOW it was able to work for 3 years with crossed wires?  Could I blow my inverter as soon as I plug in?  I am 95% sure I correctly wired both the inverter and HBs, but that 5% worries me. 

Any electrical experts out there?  Thanks in advance.

 

[SeilerBird]

It is alternating current. Polarity does not matter except for safety.

 

[Gizmo100]

Welcome to the RV Forum Ponysnake

I would be concerned about the wires being reversed....Something doesn't sound right. I'm wondering if the PO miss-wired to match some other work he may have done. I would have to go exploring into the breaker box and check everything.

 

[Gary RV_Wizard]

As Seilerbird says, reversed black & white on a 30A/120v plug is a safety concern only.  Nor does it have anything to do with the burned pins - that is simply thew result of frequent high amp loads.  Especially if it's a low quality plug.  Technically a 30A plug is rated for 30A for only about 30 minutes and some manufacturers barely meet that minimum.  For a sustained load, it is 80% of that or 24 amps. It's not unusual for a 30A coach to run at or above 24A for lengthy periods, e.g. a hot summer afternoon. The power pins get hot and slightly melt or char the nearby rubber.

 

[ChasA]

The pins and charring could also come from being plugged into a worn-out receptacle.

 

[Rene T]

The pins and charring could also come from being plugged into a worn-out receptacle.

And you should get in the habit of shutting off the breaker when you plug in then turn on the breaker. You may already be doing this but hopefully others will see this

Do you have a INverter or a CONverter?  Big difference.
A INverter takes 12 Volt DC power and changes it to 110 Volt AC.
A CONverter takes 110 Volt AC shore power and converts the power to 12 Volt ADC.

 

[Ponysnake]

Thanks to all. 
The AC/Alternating Current, of course makes sense. I will plug her into the 20 amp service here at the house tomorrow an keep my fingers crossed.

 

[Gizmo100]

As Seilerbird says, reversed black & white on a 30A/120v plug is a safety concern only.  Nor does it have anything to do with the burned pins - that is simply thew result of frequent high amp loads.  Especially if it's a low quality plug.  Technically a 30A plug is rated for 30A for only about 30 minutes and some manufacturers barely meet that minimum.  For a sustained load, it is 80% of that or 24 amps. It's not unusual for a 30A coach to run at or above 24A for lengthy periods, e.g. a hot summer afternoon. The power pins get hot and slightly melt or char the nearby rubber.

I withdraw my concern based on Seilerbird and Gary statements. And on top of that Gary gave us a education on the plugs. Something to keep in mind if I ever have to replace mine.

 

[John From Detroit]

  As SellerBird said. on A/C there really is no such thing as Polarity.  The issue is that neutral and ground are supposed to be bonded up-line somewhere (not in the RV) and in some cases if you have black and white reversed it can knock you on your..... Pride... rather easily (Had one trailer where it happened till I fixed it).

But to test.. Get a 3-light outlet tester..  Plug it into a NON GFCI outlet.