Metal two screw NM-b connector inside plastic box

resistance

Senior Member
I’m not finding anything that prohibits a metal two screw connector from being installed in a plastic box (Box has spots you can KO)? I see something in 314.3— it allows (if bonded) on raceways or MC cable—but what about NM metal cable connectors?
 

infinity

Moderator
Staff member
I would think that 250.4(A)(3) (maybe 250.4(A)(4) also) would prohibit the connector in the box. You cannot even have metal box mounting screws inside of a plastic box unless the box is designed to prevent contact with the conductors.
 
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kwired

Electron manager
I would think that 250.4(A)(3) (maybe 250.4(A)(4) also) would prohibit the connector in the box. You cannot even have metal box mounting screws inside of a plastic box unless the box is designed to prevent contact with the conductors.
but 110.12 A does say "Where metallic plugs or plates are used with nonmetallic enclosures, they shall be recessed at least 6 mm (¼ in.) from the outer surface of the enclosure."

IMO nothing wrong with metallic plugs that don't comply with that - if they are bonded somehow, same for the metal NM cable connector or any other metal fitting for that matter.
 

infinity

Moderator
Staff member
but 110.12 A does say "Where metallic plugs or plates are used with nonmetallic enclosures, they shall be recessed at least 6 mm (¼ in.) from the outer surface of the enclosure."

IMO nothing wrong with metallic plugs that don't comply with that - if they are bonded somehow, same for the metal NM cable connector or any other metal fitting for that matter.
For a 2 screw NM cable connector, how would that be bonded by placing a bonding bushing in the plastic box?
 

PaulMmn

Senior Member
I’m not finding anything that prohibits a metal two screw connector from being installed in a plastic box (Box has spots you can KO)? I see something in 314.3— it allows (if bonded) on raceways or MC cable—but what about NM metal cable connectors?
Arlington has plastic versions...
 

resistance

Senior Member
Arlington has plastic versions...
Well aware of this! I’ve always used gray plastic connectors. When I seen a j-man using metal two screw NM connectors, it raised a question of if it is allowed. I’ve always thought it wasn’t!
 

resistance

Senior Member
For a 2 screw NM cable connector, how would that be bonded by placing a bonding bushing in the plastic box?
Exactly my thoughts! I’m going to say it is not allowed! ….(NEC110.3 )No word back from Thomas N Betts—as it relates to their box.
 
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kwired

Electron manager
For a 2 screw NM cable connector, how would that be bonded by placing a bonding bushing in the plastic box?
Isn't landing a bonding jumper in the the lug on the bonding bushing the reason there is a lug?:?

And yes wedges and locknuts would need a metal box or they will serve no purpose.
 
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