One thing that caught my attention was where they say that these are the only NM cable connector listed for use in eccentric knockouts…. What?
I have to admit that is not something that ever even crossed my mind before when using any NM cable connector. I always thought that the eccentric/concentric KO concern was about grounding and bonding with metal raceways, especially for service equipment or for over 250V.
So this got me to thinking, which is never a good thing, about MC or AC and FMC type connectors used with eccentric KO’s.
Looking at MC connectors in the 2011 White book, it says they are considered suitable for grounding in circuits over and 250V, when installed in accordance with the NEC. So hopefully that means they are suitable for use with both concentric and eccentric KO’s as is, without the need for bonding bushings or grounding locknuts, even for circuits over 250V.
METAL-CLAD CABLE CONNECTORS,
TYPE MC (PJOX)
Grounding — Metal-clad cable connectors for use with metal-clad interlocking
armor ground cable, corrugated aluminum or copper tube, or
smooth aluminum tube, are considered suitable for grounding for use in
circuits over and under 250 V and where installed in accordance with
ANSI/NFPA 70, ‘‘National Electrical Code.’’