Gary RV_Wizard
Site Team
And your point is?An UL is just another privately owned entity that actually gets paid by the other entitys that want to use their stickers.
I still can't find the 80% rule for our 30 amp plugs and receptacles in my NEC book.
Suit yourself.Can any one show me where our RV 30 plugs and receptacles are referenced for 80% in NEC publications. Until so I'm going to go with more internet hooey.
If you are looking for an explicit statement about 30A receptacle ratings, I'll agree there probably is none. It's the way electrical ratings in general are done, assuming that average loads are 80% of the peak in most all types of circuits. That "80% average" assumption permeates much of the NEC rules, a major factor in defining the ampacity of wires, number of conductors in a box or conduit, number of outlets on a branch circuit, etc. etc. And yes, it effects how receptacles and plugs are tested, which in turn carries over to UL testing standards. There are also effects of temperature built into the ratings and not stated on the label.
Electrical ratings are no different than dozens of other ratings that we, the public, use as guidelines. There are always assumptions behind the ratings, and a test method or procedure for verifying the ratings. Whether the rating is an amp load, an axle or tire weight load, or safe levels of exposure to a chemical, or whatever. Most people work with a simplified rating value rather than learning the ins and outs of each thing.
I merely offer this as an explanation as to why 30A plugs and receptacle sometimes appear blacked or even melted but the breaker didn't trip. You don't have to accept it.