More than anyone will ever care to know about AC Circuit Breakers is here:
On page 26 you will see something called the Time-Current Curve.
It is rated in seconds per l(n) where l is the breaker rating and the (n) is the number of MULTIPLES of that rating. The more multiples of the rating the faster the trip.
For example a 30 amp breaker will never trip with a continuous current of 30 amps.
At 120 amps l(4) the breaker will open in 1 second.
On page 27, smaller overloads and the time to trip can be determined.
At 45 amps l(1.5) it will take 1000 seconds (almost 17 minutes) to trip.
On page 28 they use l(1.25) as an example of the overload required to trip at the 10,000 second point.
At 1.25 times a 30 amp breaker = 37.5 amps and it will take 2 hours and 45 minutes to trip the breaker. Long enough to do serious damage to your cord's connections.
And that my friends is the real story.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW