Ryan,
Don, take a look at the 2005 UL White book, and it will show that the combo types are supposed to open on a series arc,
I don't buy it...they went to great lengths to show that there is no such thing as a series arc a few years ago. They proved that you couldn't sustain a series arc at 120 volts. While the UL information uses the term series arc there is nothing in the testing information for any of the AFCI listing types that says anything about testing for a series arc. They imply it in this section, but in reading it closely they are still only testing for a parallel arc. More misinformation designed to scam the code writers and the public. (as you can see I have no trust for any organization involved in this issue)
56.4 Carbonized Path Arc Clearing Time Test -
This test is a non-contact arcing test conducted with SPT-2 flexible cord and NM-B cable. For test purposes a parallel insulation cut is made, but test currents are
limited to series (load) current values. Tests are conducted with arcing currents of 5A, 10A, rated current, and 150% rated current. Acceptable performance is clearing the arc fault in a specified time ranging from 1 second at 5A to less than 200 milliseconds at 150% of rated current.
Don
