Pancake box support

Old 08-31-03, 11:29 AM
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Pancake box support

Is it a violation of the NEC to screw into an air duct to support a pancake box? While remodeling, I have encountered a situation where I want to put in wall sconces and an air duct is in the way. The only way to get the placement to work is to screw into the duct to support the box. The sconces are very lite weight and the duct is sturdy.

Old 08-31-03, 05:40 PM
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Not the answer you want.

I'm afraid the answer to your question is no. Not only does it not meet the requirements of the electric code for the support of boxes that I have quoted below but it also violates the mechanical code as adopted in many jurisdictions. If you have enough room you can use a box brace and a pancake box but that would take at least one inch of useable depth from the face of the wall to the duct.

The other possibility is to use an old work pancake box that is supported by the wall finish itself. That is covered by the language in section C below.

314.23 Supports.
Enclosures within the scope of this article shall be supported in accordance with one or more of the provisions in 314.23(A) through (H).
(A) Surface Mounting. An enclosure mounted on a building or other surface shall be rigidly and securely fastened in place. If the surface does not provide rigid and secure support, additional support in accordance with other provisions of this section shall be provided.
(B) Structural Mounting. An enclosure supported from a structural member of a building or from grade shall be rigidly supported either directly or by using a metal, polymeric, or wood brace.
(1) Nails and Screws. Nails and screws, where used as a fastening means, shall be attached by using brackets on the outside of the enclosure, or they shall pass through the interior within 6 mm (1/4 in.) of the back or ends of the enclosure.
(2) Braces. Metal braces shall be protected against corrosion and formed from metal that is not less than 0.51 mm (0.020 in.) thick uncoated. Wood braces shall have a cross section not less than nominal 25 mm 50 mm (1 in. 2 in.). Wood braces in wet locations shall be treated for the conditions. Polymeric braces shall be identified as being suitable for the use.
(C) Mounting in Finished Surfaces. An enclosure mounted in a finished surface shall be rigidly secured thereto by clamps, anchors, or fittings identified for the application.

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