electrical breakers puzzle
Here's how you test a breaker

First, you need to get some hard numbers as to the actual load you are putting on the breaker.  So get a Kill-a-watt and see what your various loads actually do draw in amps (test them individually). 

Now you are looking to test the breaker, not set the wiring in your home on fire, so don't draw this through the house's wiring.  Build a little test box out of a 4x4 metal junction box, #10 cable, and 2 twin receptacles, and strip the #10 cable back about a foot.  Ground to ground bar, neutral to neutral bar, and hot directly to the breaker under test.   Plug all your loads into the receptacles. 

OK, you want to test the breaker.  Go get the breaker's trip-curve chart.  



Look up the amps you will be applying, say it's 40 amps. That's 200% of the breaker rating, so find 200% on the horizontal chart for your breaker (not this example)... and follow the 200% line up to the number of seconds the line enters and exits the "gray area".   In this example, it's 9 seconds and 35 seconds.  

Turn on your loads and stopwatch... your breaker should trip between 9 and 35 seconds later.  (maybe a smidge longer if the load is causing voltage to sag). 

That's a thermal trip mode. 

The magnetic trip is an instant trip based on high excess current.  That is the horizontal blob at the bottom of the chart.  Flow 15x rated current and you should get a nice instant magnetic trip inside one AC cycle (&lt;=20ms).