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Wire passing through metal framing

Question asked by randy.hartwick on Nov 17, 2016
Latest reply on Nov 28, 2016 by brian.baughman

I am trying to determine if edge protection, such as a grommet, is required when running Romex through our product. We manufacture a formed and stamped metal framing system which includes holes for wire to pass through. Unlike typical metal studs which have punched holes with sharp edges, our product is made up of two layers of sheet metal and the holes are pressed so that the entire edge of the hole is folded over 180 degrees (like a hemmed edge). This holds the two layers of sheet metal together and produces a smooth edged opening that will not cut or damage the non-metallic sheathing of Romex.


I read NFPA 70, which states in article 300:

300.4 Protection Against Physical Damage.
Where subject to physical damage, conductors shall be protected.
(B) Nonmetallic-Sheathed Cables and Electrical Nonmetallic Tubing Through Metal Framing Members.
(1) Nonmetallic-Sheathed Cable. In both exposed and concealed locations where nonmetallic-sheathed cables pass through either factory- or field-punched, cut, or drilled slots or holes in metal members, the cable shall be protected by listed bushings or listed grommets covering all metal edges that are securely fastened in the opening prior to installation of the cable.

This requirement specifically states punched, cut or drilled holes, which would most likely have sharp edges. Since our product has an integral grommet (even though it is metallic), would a grommet still need to be installed? If anyone has more detail on this or knows of an ASTM Standard Test Method or Specification I can use to qualify our product for use without an additional grommet, it would be greatly appreciated. Thanks in advance for any help.