clamp for metallic cable

[Sam Takoy]

Hi,

I need to put in a metallic cable into a plastic box. Is there a type of clamp that would secure it and provide a way of grounding.

Thanks,

Sam

[RBM]

No there isn't. It is not legal to run metallic cables into plastic boxes.

[gfretwell]

I have heard opinions that if you used a bonding bushing in the box it would meet the spirit of the code but you won't find the code language.

[gfretwell]

This is the language you exploit

314.3 Nonmetallic Boxes. Nonmetallic boxes shall be permitted only with open wiring on insulators, concealed knob-and-tube wiring, cabled wiring methods with entirely nonmetallic sheaths, flexible cords, and nonmetallic raceways. Exception No. 1: Where internal bonding means are provided between all entries, nonmetallic boxes shall be permitted to be used with metal raceways or metal-armored cables.

[bud--]

A bonding bushing seems reasonable, but then you need knockouts in a plastic box.

[RogerT]

Can someone explain what "Where internal bonding means are provided between all entries" means in English?

[Tom Horne]

It means that either the installer or the manufacturer provides the means to connect all of the metallic raceways or cable jackets that connect to the box to each other and to the equipment grounding conductors. Installing half inch bonding bushings will work but it is tedious. A strip of galvanized steel flashing that has holes in it at each knock out would also work. Sometimes you can obtain plastic boxes with a bonding strip installed at the factory.

-- Tom Horne

[willshak]

almost halfway down the page

[jw]

For crying out loud, just use a friggin metal box and be done with it. It will likely cost an additional half a dollar or less.

[Tom Horne]

It is probably an existing plastic box.

-- Tom Horne

[RogerT]

Thanks.