What is the point of the NEC's 80% maximum load on a circuit?

wildmancasey · #1 (**permalink**) 12-08-2007, 06:00 PM

I mean if most breakers are rated to trip at 80% for 3 hours why have the code if the breaker will just trip? Also if I have a 20a receptacle by itself on a circuit, with a 20a breaker and a 100' #10 cord connected with 18.5a of Christmas Lights at the end, is this dangerous/bad?

sparky · #2 (**permalink**) 12-09-2007, 10:41 PM

If you have any questions about anything electrical, the best course of action would be to contact your local Electrical Inspector. One of the very first things the NEC says is that all codes are "subject to the authority having jurisdiction". That being said, if the breaker isn't tripping on your Christmas lights then your fine. # ten wire is rated for 30 amps so you don't have to worry about the cord.

William B · #3 (**permalink**) 12-10-2007, 11:16 PM

the propose of having an 80% load is to keep from burning the breaker up, and causeing a short, &fire, if there wasnt a code manafactures could make them any way they wanted to, the lights thats fine, you did right, as long as the #18 cord doesnt heat up it will be ok,