I am currently dealing with a little confusion regarding arc fault protection and how it would be enforced by 2016 NEC code. I'm not a licensed electrician, I'm doing an apprenticeship and the guy overseeing my work is unavailable right now, was hoping for some advice. I ran a branch circuit to a shared switch box consisting of 2 - 3 way switches powering independent lighting circuits. I used a 14/3 cable not being aware he was enforcing this code. (I haven't seen it enforced much around here in my experience). I was am now being told that you can not share a common neural and still arc fault protect them. I think I may have found a way if I were to use a 2- pole 15 amp breaker they would only need one neutral, correct? Is this violating any other NEC codes in the process by them having a common trip? Also I am finding GE has discontinued 2 pole afci breakers. I would have to order online to match the load center but does anyone have any idea as to why they stopped making them? Were they having trouble with the functionality? Any advice you guys may have would be a big help. Thanks
Unfortunately most AHJ's these days require some form of fault protection... whether it be GFCI, AFCI, CAFCI, or the newer DFCI. DFCI's have class A GFCI protection ( 5mA trip) unlike their former cousins CAFCIs which are more of an equipment GFCI (30mA trip) with Arc fault protection too.
Maybe you can use a discontinued double pole AFCI. Good question on why they discontinued some of the AFCIs. Probably not enough demand and not required by Code.
By the way, the guy overseeing your work should technically be your Boss, legally he cannot sub you out as a independent contractor since you're not liscesned.
GE (THQL) AFCIs don't come in two pole any longer -- because they don't need to
Your apparent lack of ability to find two pole THQL AFCIs is actually due to a manufacturing revision to the single pole units. Mod 3 single pole THQL AFCI breakers can be handle-tied for multiple pole applications, as they do not use a CT-based trip for arc-to-ground detection. (You still need to wire the load neutral to one of the AFCIs, but either one will do -- you don't need to connect it to both.)
See this GE handout for details.