C.O.F. - Certificate of Fitness. I moved into management many years ago and just couldn't keep up with the required continuing education and time to study/sit for exams to keep mine current.
There are combination AFCI/GFCI breakers now. They open if either ground or arc fault is detected. Expensive and somewhat new'ish tech, but are becoming more mainstream..... Single-function AFCI or GFCI do not protect for both faults, to the best of my knowledge.
Just for clarification, the vast majority of residential wiring is single phase. Two-phase power generation was replaced by three-phase power decades ago. The residential feed is two 120V legs of three-phase power supply from the transformer, with one neutral. Commercial power will generally have all three phases ran to the building. So technically - your home is single phase, even 240V circuits.
