Results 1 to 18 of 18
  1. #1
    Join Date
    Feb 2011
    Location
    Ohio
    Posts
    73

    Default Light fixture on metal heating duct.

    Anyone know if there is a code prohibiting installing a light fixture on
    metal heating ductwork like this. (Basement. Conduit runs along duct, box is screwed into the duct)


    Thanks




    Similar Threads:
    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    NHIE Practice Exam

  2. #2
    Join Date
    Mar 2007
    Location
    Philadelphia PA
    Posts
    3,177

    Default Re: Light fixture on metal heating duct.

    Good grief. If there isn't a code prohibition, there should be.
    I don't suppose the metal duct is bonded?

    "There is no exception to the rule that every rule has an exception." -James Thurber, writer and cartoonist (1894-1961)
    www.ArnoldHomeInspections.com

  3. #3
    Join Date
    Feb 2011
    Location
    Ohio
    Posts
    73

    Default Re: Light fixture on metal heating duct.

    I LOVE that quote. So true!


  4. #4
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Light fixture on metal heating duct.

    Acceptable supports for that boxes are listed below: I did not post the nitty-gritty within each subsection, just the subsection headings.
    - ARTICLE 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures
    - - 314.23 Supports.
    - - - (A) Surface Mounting.
    - - - (B) Structural Mounting.
    - - - (C) Mounting in Finished Surfaces.
    - - - (D) Suspended Ceilings.
    - - - (E) Raceway Supported Enclosure, Without Devices, Luminaires, or Lampholders.
    - - - (F) Raceway-Supported Enclosures, with Devices, Luminaires, or Lampholders.
    - - - (G) Enclosures in Concrete or Masonry.
    - - - (H) Pendant Boxes.

    I don't see 'Duct-Supported Enclosures' in the above.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  5. #5
    Join Date
    Feb 2011
    Location
    Ohio
    Posts
    73

    Default Re: Light fixture on metal heating duct.

    Thank you Jerry! I appreciate it.


  6. #6
    Join Date
    Oct 2010
    Location
    Southwest US
    Posts
    585

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by John Arnold View Post
    Good grief. If there isn't a code prohibition, there should be.
    I don't suppose the metal duct is bonded?
    Metal conduit, it is now!


  7. #7
    John Steinke's Avatar
    John Steinke Guest

    Default Re: Light fixture on metal heating duct.

    There's no NEC specification that addresses what you can hang your boxes from. Or, for that matter, how you hang them.

    There might be a rule in the mechanical code, but that's for others to find.

    There's no requirement that the ducts be bonded- just the box.

    You don't have to like it. Just be sure to be clear that it's your opinion.


  8. #8
    Join Date
    Feb 2011
    Location
    Ohio
    Posts
    73

    Default Re: Light fixture on metal heating duct.

    According to Jerry, there are codes on where electrical box can be installed.
    See below
    ---------------------------------------------------------------------

    Acceptable supports for that boxes are listed below: I did not post the nitty-gritty within each subsection, just the subsection headings.
    - ARTICLE 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures
    - - 314.23 Supports.
    - - - (A) Surface Mounting.
    - - - (B) Structural Mounting.
    - - - (C) Mounting in Finished Surfaces.
    - - - (D) Suspended Ceilings.
    - - - (E) Raceway Supported Enclosure, Without Devices, Luminaires, or Lampholders.
    - - - (F) Raceway-Supported Enclosures, with Devices, Luminaires, or Lampholders.
    - - - (G) Enclosures in Concrete or Masonry.
    - - - (H) Pendant Boxes.

    I don't see 'Duct-Supported Enclosures' in the above.


  9. #9
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by John Steinke View Post
    There's no NEC specification that addresses what you can hang your boxes from. Or, for that matter, how you hang them.

    There might be a rule in the mechanical code, but that's for others to find.

    There's no requirement that the ducts be bonded- just the box.

    You don't have to like it. Just be sure to be clear that it's your opinion.
    John,

    Read the code section through and through, you should be able to understand it. I am out camping and do not have my codes loaded into my new notebook, so I am not able to post the entire code sections I gave, but if you read those, you will see that the duct is not a suitable support for the light fixture.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  10. #10
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
    Posts
    4,549

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by John Steinke View Post
    There's no NEC specification that addresses what you can hang your boxes from. Or, for that matter, how you hang them.

    There might be a rule in the mechanical code, but that's for others to find.

    There's no requirement that the ducts be bonded- just the box.

    You don't have to like it. Just be sure to be clear that it's your opinion.
    We don't have to like your reply either.

    I would not allow that in my basement, and I would call for it to be removed on any inspection I am involved with. Call it an opinion if you wish. Too easy for a loose connection to cause the ductwork to be energized.

    You can't expect to find prohibitions for every kind of ignorance in a code book.

    Last edited by John Kogel; 03-26-2011 at 08:57 AM.
    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  11. #11
    Join Date
    Dec 2007
    Location
    Chico,Ca
    Posts
    423

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by John Kogel View Post
    We don't have to like your reply either.

    I would not allow that in my basement, and I would call for it to be removed on any inspection I am involved with. Call it an opinion if you wish. Too easy for a loose connection to cause the ductwork to be energized. Also, the wiring, likely NMD, is enclosed inside a heat duct. Besides the heat, Rodents like to chew things in heat ducts, don't they?

    You can't expect to find prohibitions for every kind of ignorance in a code book.

    Since when is a surface mounted conduit inside a duct?? If the wiring was in the duct, NM, EMT, or whatever it would it have to go, but since it's surface mounted I see nothing prohibiting it.


  12. #12
    Join Date
    Feb 2009
    Location
    Southern Vancouver Island
    Posts
    4,549

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by Rollie Meyers View Post
    Since when is a surface mounted conduit inside a duct?? If the wiring was in the duct, NM, EMT, or whatever it would it have to go, but since it's surface mounted I see nothing prohibiting it.
    Thanks, RM. I must have been going blind last night.

    John Kogel, RHI, BC HI Lic #47455
    www.allsafehome.ca

  13. #13
    Join Date
    Jul 2008
    Location
    Snowbird (this means I'm retired and migrate between locations), FL/MI
    Posts
    4,086

    Default Re: Light fixture on metal heating duct.

    Since few are accessing the most current standards/safety/codes (2011 NEC), I'll use 2008 NEC references below.

    See first Secs. 410.30 & 410.36(A) & (E).

    Even IF the outlet box was ADDITIONALLY raceway supported {314.23(F) method as permitted by reference in 314.23(A) Surface mounting...additional support} it does not meet 314.23(F), nor its Ex. No. 1, nor Ex. No. 2 "all";, specifically 314.23(F)Ex. No. 2(c); Therefore, box supporting luminaire is not as indicated as "surface mounted" sufficiently supported (not rigidly for example) by its MERE attachment to the heat duct, it would still not allowed to support the (lightweight though it may be). Can't rely upon 314.27(A) as is not met - box is neither IN a ceiling no IN a wall, so to support luminaire, box must at minimum (any weight of luminaire to be supported less than 50 lbs) meet 314.27(B) which requires box installed to support as per 314.23; as required by 410.36(A) which requires that for the outlet box to support the luminaire it must be installed to support per 314.23 AND meet 314.27(A) AND meet 314.27(B).

    A listed box has listing requirements regarding its use. There is a rules test for floor/ceiling assemblies or overhead mounted boxes regarding weight applied and time held, this has been discussed and supported with documentation on other threads.

    As luminaire is present, conductive box, and in non-habital space, Unfinished, overhead (questionably withIN 8' clearance of walk surface or floor) basement uninsulated wall shown, would be further interested to know IF:

    Entire luminiare, the box, the conduit, and the lower plane of the metalic conductive duct is 8 ft clearance above the floor surface - and three ft horizontal from the (glass block though it may be) window. If GFCI protected, if 2-wire; and if the floor is considered a conductive surface (concrete, etc.). From the arrangement of the plumbing pipes on the back wall, belive it is further fair to presume the presence of a laundry sink or washing machiine connections - dual purpose for the area not merely environmental air. I am going to presume it is in fact a laundry area beyond pictured under, and to the left and right of the block window and along the far wall as pictured.

    Article 410 Part IV Luminaire Suports

    410.30 Supports.
    -(A) General. Luminaires and lampholders shall be securely supported...


    410.36 Means of Support.
    -(A) Outlet Boxes. Outlet boxes or fittings installed as required by 314.23 and complying with the provisions of 314.27(A) and 314.27(B) shall be permitted to support luminaires.
    -(B) Suspended Ceilings. Framing members of suspended ceiling systems used to support luminaires shall be securely fastened to each other and shall be securely attached to the building structure at apprpriate intervals. Luminaires shall be securely fastened to the ceiling framing member by mechanical means such as bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member(s) and luminaire(s) shall also be permitted.
    -(C) Luminaire Studs. Luminaire studs that are not a part of outlet boxes, hickeys, tripods, and crowfeet shall be made of steel, malleable iron, or other materials suitable for the application.
    -(D) Insulating Joints. Insulating joints that are not designed to be mounted with screws or bolts shall have an exterior matal casing, insulated from both screw connections.
    -(E) Raceway fittings. Raceway fittings used to support a luminaire(s) shall be capable of supporting the weight of the complete fixture assembly and lamp(s).
    -(F) Busways. Luminaires shall be permitted to be connected to busways in accordance with 368.17(C).
    -(G) Trees. Outdoor luminaires and associated euqipment shall b e permitted to be supported by trees.
    --FPN No. 1: See 225.26 for restrictions for support of overhead conductors.
    --FPN No. 2: See 300.5 for protection of conductors.

    Art. 410 Part V Grounding

    410.40 General. Luminaires and lighting equipment shall be grounded as required in Article 250 and Part V of this article.


    410.42 Exposed Luminaire.
    -(A) Exposed Conductive Parts. Exposed metal parts shall be connected to an equipment grounding conductor or insulated from the equipment grounding conductor and other conducting surfaces or be inacessible to unqualified personnel. Lamp tie wiries, mounting screws, clips, and decorative bands on glass spaced at least 38 mm (1-1/2 in.) from lamp terminals shall not be required to be grounded.
    -(B) Made of insulating Material. Luminaires directly wired or attached to outlets suppied by a wiring method that does not provide a ready means for grounding attachment to an equipment grounding conductor shall be made of insulating material and shall have no exposed conductive parts.
    --Exception No. 1: Replacement luminaires shall be permitted to connect to an equipment grounding conductor from the outlet in compliance with 250.130(C). The luminaire shall then comply with 410.42(A).
    --Exception No. 2: Where no equipment grounding conductor exists at the outlet, replacement luminaires that are GFCI protected shall not be required to be connected to an equipment grounding conductor.


    410.44 Equipment Grounding Conductor Attachment. Luminaires with exposed metal parts shall be provided with a means for connecting an equipment grounding conductor for such luminaires.


    410.46 Methods of Grounding. Lumianires and equipment shall be mechanically connected to an equipment grounding conductor as specified in 250.118 and sized in accordance with 250.122.


    Art. 410 Part VI Wiring of Luminaires.


    410.48 Luminaire Wiring -- General. Wiring on or within luminaires shall be neatly arranged and shall not be exposed to physical damage. Excess wiring shall be avoided. Conductors shall be arranged so that they are not subjected to temperatures above those for which they are rated.

    410.52 Conductor Insulation. Luminaires shall be wired with conductors having insulation suitable for the environmental conditions, current, voltage, and temperature to which the conductors will be subjected.
    -FPN: For ampacity of fixture wire, maximum operating temperature, voltage limitations, minimum wire size, and so forth, see Article 402.






    310.10 Temperature Limition of Condutors. No conductor shall be used in such a manner that its operating temperature exceeds that designated for the type of insulated conductor involved. In no case shall conductors be associated together in such a way, with respect to type of circuit, the wiring method employed, or the number of conductors, that the limiting temperature of any conductor is exceeded.
    The surface of a FA heating duct, uninsulated, and without a thermal break between it and the metalic outlet box screwed thereto (and without a gasket for air leakage) IMO is an "environment" which exceeds 86F ambient, further the "heat" from continuous operation of incandenscent luminaire would likely exceed even if not operatied. Ask yourself what is the temperature of the heated FA via the duct so near the source (HE)? 160 F? 140 F? 135F?. Further, sheet metal without interior metal brace at point of contact would not be "surely" fastened so as to prevent movement, flex, etc. due to temperature changes. Next, could it be an outlet box supported by conduit or tubing, which then (the box) supports a lightweight luminaire....i.e. NO screws or attachment of the "box" to the duct, plenum, trunk, above..(but that's not what the Original Poster has indicated):
    Condensation, no gasket, isolator, protection or closure from attachment screws, entry of condensation (collecting on duct exterior) in unconditioned, uninsulated (masonry wall interior exposed, no insulation), apparent LAUNDRY AREA, indicated by dryer vent passing through block window, and suggested by plumbing upon the wall pictured beyond the luminaire.
    NEC has considered a laundry area in a dwelling, or residential, at a minimum a damp location regards safety of persons. It (laundry area outlet for washing machine) was the FIRST to REQUIRE a grounding type receptacle (IIRC two code cycles before) the use of grounding type receptacles were required elsewhere in residential construction. As an unfinished, non-habital, non-conditioned, non-insulated area of this basement - and apparently also a laundry area, I won't engage further on this issue with those known to ignore plain language defining such areas.
    A listed residential washer has a means to eject overflow path should compartment be overfilled, to the floor by design which protects internal wiring. As suggested by the presence of plumbing pictured on the wall - beyond the luminaire, it is further suggested that beneath same would be a likely path of a person to travel (on the floor) to get to the washing machine to disconnect it or turn it off, and to shut off the supply of water (should for example the float switch in the machine fail and over-fill the washing compartment). Hence the earlier curousity regarding the HEIGHT of the unguarded lamp, the luminaire, the outlet box to which it is mounted above the (finished or unfinshed) "floor" or walking surface - and its proximity horizontally to the "window" pictured (block or not is not specified).
    314.15 Damp or Wet Locations. In damp or wet locations, boxes, conduit bodies, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the bos, conduit body, or fitting. Boxes, conduit bodies, and fittings installed in wet locations shall be listed for use in wet locations.
    Collected condensation upon duct above and entry into box via "screws" attaching box to duct in "laundry area" or in "basement".
    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. Screws shall not be permitted to pass through the box unless exposed threads in the box are protected using approved means to avoid abrasion of conductor insulation.
    --(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 x 50 mm (1 in. x 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 fitings identified for the application.
    -(D) Suspended Ceilings. An enclosure mounted to structural or supporting elements of a suspended ceiling shall be not more than 1650 (cubic) cm (100 (cubic) in.) in size and shall be securely fastened in place in accordance with either (D)(1) or (D)(2).
    --(1) Framing Members. An enclosure shall be fastened to the framing members by mechanical means such as bolts, screws, or rivets, or by the use of clips or other securing means identified for use with the type of ceiling framing member(s) and enclsoure(s) employed. The framing members shall be adequately supported and securely fastened to each other and to the building structure.
    --(2) Support Wires. The installation shall comply with the provisiions of 3011(A). The enclosure shall be secured, wiring methods identified for the purpose, to ceiling support wire(s), including any additional suport wire(s) installed for that purpose. Support wire(s) used for enclosure support shall be fastened at each end so as to be taut within the ceiling cavity.
    -(E) Raceway Supported Enclosure, Without Devices, Luminaires, or Lampholders. An enclosure that does not contain a device(s) other than splicing devices or support a luminaire(s), lampholder, or other equipment and is supported by entering raceways shall not exceed 1650 cubic cm (100 cu. in.) in size. It shall have threaded entries or have holes identified for the purpose. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 900 mm (3 ft) of the enclosure, or within 450 mm (18 in.) of the enclosure if all conduit entries are on the same side.
    --Exception: Rigid metal, intermediate metal, or rigid non-metallic conduit or electrical metallic tubing shall be permitted to support a conduuit body of any size, including a conduit body constructed with only one conduit entry, provided the trade size of the conduit body is not larger than the largest trade size of the conduit or electrical metallic tubing.
    -(F) Raceway-Supported Enclosures, with Devices, Luminaires, or Lampholders. An enclosure that contains a device(s), other than splicing devices, or supports a luminaire(s), lampholder, or other equipment and is supported by entering raceways shall not exceed 150 cu. cm (100 cu. in) in size. It shall have threaded entries or have hubs identified for the purpose. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 450 mm (18 in.) of the enclosure.
    --Exception No. 1: Rigid metal or intermediate metal conduit shall be permitted to support a conduit body of any size, including a conduit body constructed with only one conduit entry, provided the trade size of the conduit body is not larger than the largest trade size of the conduit.
    --Exception No. 2: An unbroken length(s) of rigid or intermediate metal conduit shall be permitted to support a box used for a luminaire or lampholder support, or to support a wiring enclsure that is an integral part of a luminaire and used in lieu of a box in accordance with 300.15(B), where all of the following conditions are met:
    ---(a) The conduit is securely fastened at a point so that the length of conduit beyond the last point of conduit support does not exceed 900 mm (3 ft).
    ---(b) The unbroken conduit length before the last point of conduit support is 300 mm (12 in.) or greater, and that the portion of the conduit is securely fastened at some point not less than 300 mm (12 in.) from its last point of support.
    ---(c) Where accessible to unqualified persons, the luminaire or lampholder, measured to its lowest point, is at least 2.5 m (8 ft) above grade or standing area and at least 900 mm (3 ft) measured horizontally to the 2.5 m (8 ft) elevation from windows, doors, porches, fire escapes, or similar locations.
    ---(d) A luminaire supported by a single conduit does not exceed 300 (12 inc.) in any direction from the point of conduit entry.
    (e) The weight supported by any single conduit does not exceed 9 kg (20 lb).
    ---(f) At the luminaire or lampholder end, the conduit(s) is threaded wrenchtight into the box, conduit body, or integral wiring enclosure, or into hubs identified for the purpose. Where a box or conduit body is used for support, the luminaire shall be secured directly to the box or conduit body, or though a threaded conduit nipple not over 75 mm (3 in.) long.

    -(G) Enclousres in Concrete or Masonry. An enclousre supported by embedment shall be identified as suitably protected from corrosion and securely embedded in concrete or masonry.
    -(H) Pendant Boxes. An enclosure supported by a pendant shall comply with 314.23(H)(1) or (H)(2).
    --(1) Flexible Cord. A box shall be supported from a multiconductor cord o cable in an approved manner that protects the conductors against strain, such as a strain-relief connector threaded into a box with a hub.
    --(2) Conduit. A box supporting lampholders or luminaires, or wiring enclosures within luminaires used in liew of boxes in accordance with 300.15(B), shall be supported by rigid or intermediate metal conduit stems. For stems longer than 450 mm (18 in.), the stems shall be connected to the wiring system with flexible fittings suitable for the locatin. At the luminaire end, the conduit(s) shall be threaded wrenchtight into the box or wiring enclosure, or into hubs identified for the purpose.
    Where supported only by a single conduit, the threaded joints shall be prevented from loosening by the use of set-screws or other effective means, or the luminaire, at any point, shall be at least 2.5 m (8 ft) above grade or standing area and at least 900 mm (3 ft) measured horizontally to the 2.5 m (8 ft) elevation from windows, doors, porches, fire escapes, or similar locations. A luminaire supported by a single conduit shall not exceed 300 mm (12 in.) in any horizontal direction from the point of conduit entry.

    314.27 Outlet Boxes.

    -(A) Boxes at Luminaire Outlets. Boxes used at luminaire or lampholder outlets in a ceiling shall be designed for the purpose and shall be required to support a luminaire weighing a minimum of 23 kg (50 lb). Boxes used at luminaire or lampholder outlets in a wall shall be designed for the purpose and shall be marked on the interior of the box to indicate the maximum weight of the luminaire that is permitted to be supported by the box in the wall, if other than 23 kg (50 lb). At every outlet used exclusively for lighting, the box shall be designed or installed so that a luminaire may be attached.
    --Exception: A wall-mounted luminaire weighing not more than 3 kg (6 lb) shall be permiteed to be supported on other boxes or plaster rings that are secured to other boxes, provided the luminaire or its supporting yoke is secured to the box with no fewer than two No. 6 or larger screws.
    -(B) Maximum Luminaire Weight. Outlet boxes or fittings designed for the support of luminaires and installed as required by 314.23 shall be permitted to support a luminare weighing 23 kg (50 lb) or less. A luminaire that weights more than 23 kg (50 lb) shall be supported independently of the outlet box unless the outlet box is listed and marked for the maximum weight to be supported.


    Bottom Line, Surface mounted but raceway supported 314.23(F) still has to meet all criteria, including above walk surface and away from window, and the general provisions for the conditions, including temperature environment - heat duct trunk without thermal break and not rigid and without gasket or sealing exposes box, conductors, luminaire wiring, luminaire itself to higher temperatures, ambient so as not to accomodate operating temperatures, and proximity to floor - and environment of installation (laundry area, unfinished, occupiable, not habital, unfinished basement) and subject to condensation, etc. So, and without proof that metal support interior to the duct which provides rigidity and support at connection point - I'd say NOPE, until proven otherwise. Now, if the duct is purely for AC - still NO - without sealing/gasket from screws connecting box to sheet metal above - subject to condensation entry into box via screw threads - and condensation collection on exterior of box entering luminaire. No guard for lamp either - hazard. BTW looks like vibration or otherwise (duct flex due to temps?) has caused the lamp to fail - appears "burnt out". :P










    ***IMPORTANT*** You Need To Register To View Images ***IMPORTANT*** You Need To Register To View Images
    Last edited by H.G. Watson, Sr.; 03-26-2011 at 11:44 AM.

  14. #14
    Join Date
    Aug 2008
    Location
    Maryland
    Posts
    1,899

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Since few are accessing the most current standards/safety/codes (2011 NEC), I'll use 2008 NEC references below.

    See first Secs. 410.30 & 410.36(A) & (E).

    Even IF the outlet box was ADDITIONALLY raceway supported {314.23(F) method as permitted by reference in 314.23(A) Surface mounting...additional support} it does not meet 314.23(F), nor its Ex. No. 1, nor Ex. No. 2 "all";, specifically 314.23(F)Ex. No. 2(c); Therefore, box supporting luminaire is not as indicated as "surface mounted" sufficiently supported (not rigidly for example) by its MERE attachment to the heat duct, it would still not allowed to support the (lightweight though it may be). Can't rely upon 314.27(A) as is not met - box is neither IN a ceiling no IN a wall, so to support luminaire, box must at minimum (any weight of luminaire to be supported less than 50 lbs) meet 314.27(B) which requires box installed to support as per 314.23; as required by 410.36(A) which requires that for the outlet box to support the luminaire it must be installed to support per 314.23 AND meet 314.27(A) AND meet 314.27(B).

    A listed box has listing requirements regarding its use. There is a rules test for floor/ceiling assemblies or overhead mounted boxes regarding weight applied and time held, this has been discussed and supported with documentation on other threads.

    As luminaire is present, conductive box, and in non-habital space, Unfinished, overhead (questionably withIN 8' clearance of walk surface or floor) basement uninsulated wall shown, would be further interested to know IF:

    Entire luminiare, the box, the conduit, and the lower plane of the metalic conductive duct is 8 ft clearance above the floor surface - and three ft horizontal from the (glass block though it may be) window. If GFCI protected, if 2-wire; and if the floor is considered a conductive surface (concrete, etc.). From the arrangement of the plumbing pipes on the back wall, belive it is further fair to presume the presence of a laundry sink or washing machiine connections - dual purpose for the area not merely environmental air. I am going to presume it is in fact a laundry area beyond pictured under, and to the left and right of the block window and along the far wall as pictured.

    Article 410 Part IV Luminaire Suports

    410.30 Supports.
    -(A) General. Luminaires and lampholders shall be securely supported...


    410.36 Means of Support.
    -(A) Outlet Boxes. Outlet boxes or fittings installed as required by 314.23 and complying with the provisions of 314.27(A) and 314.27(B) shall be permitted to support luminaires.
    -(B) Suspended Ceilings. Framing members of suspended ceiling systems used to support luminaires shall be securely fastened to each other and shall be securely attached to the building structure at apprpriate intervals. Luminaires shall be securely fastened to the ceiling framing member by mechanical means such as bolts, screws, or rivets. Listed clips identified for use with the type of ceiling framing member(s) and luminaire(s) shall also be permitted.
    -(C) Luminaire Studs. Luminaire studs that are not a part of outlet boxes, hickeys, tripods, and crowfeet shall be made of steel, malleable iron, or other materials suitable for the application.
    -(D) Insulating Joints. Insulating joints that are not designed to be mounted with screws or bolts shall have an exterior matal casing, insulated from both screw connections.
    -(E) Raceway fittings. Raceway fittings used to support a luminaire(s) shall be capable of supporting the weight of the complete fixture assembly and lamp(s).
    -(F) Busways. Luminaires shall be permitted to be connected to busways in accordance with 368.17(C).
    -(G) Trees. Outdoor luminaires and associated euqipment shall b e permitted to be supported by trees.
    --FPN No. 1: See 225.26 for restrictions for support of overhead conductors.
    --FPN No. 2: See 300.5 for protection of conductors.

    Art. 410 Part V Grounding

    410.40 General. Luminaires and lighting equipment shall be grounded as required in Article 250 and Part V of this article.


    410.42 Exposed Luminaire.
    -(A) Exposed Conductive Parts. Exposed metal parts shall be connected to an equipment grounding conductor or insulated from the equipment grounding conductor and other conducting surfaces or be inacessible to unqualified personnel. Lamp tie wiries, mounting screws, clips, and decorative bands on glass spaced at least 38 mm (1-1/2 in.) from lamp terminals shall not be required to be grounded.
    -(B) Made of insulating Material. Luminaires directly wired or attached to outlets suppied by a wiring method that does not provide a ready means for grounding attachment to an equipment grounding conductor shall be made of insulating material and shall have no exposed conductive parts.
    --Exception No. 1: Replacement luminaires shall be permitted to connect to an equipment grounding conductor from the outlet in compliance with 250.130(C). The luminaire shall then comply with 410.42(A).
    --Exception No. 2: Where no equipment grounding conductor exists at the outlet, replacement luminaires that are GFCI protected shall not be required to be connected to an equipment grounding conductor.


    410.44 Equipment Grounding Conductor Attachment. Luminaires with exposed metal parts shall be provided with a means for connecting an equipment grounding conductor for such luminaires.


    410.46 Methods of Grounding. Lumianires and equipment shall be mechanically connected to an equipment grounding conductor as specified in 250.118 and sized in accordance with 250.122.


    Art. 410 Part VI Wiring of Luminaires.


    410.48 Luminaire Wiring -- General. Wiring on or within luminaires shall be neatly arranged and shall not be exposed to physical damage. Excess wiring shall be avoided. Conductors shall be arranged so that they are not subjected to temperatures above those for which they are rated.

    410.52 Conductor Insulation. Luminaires shall be wired with conductors having insulation suitable for the environmental conditions, current, voltage, and temperature to which the conductors will be subjected.
    -FPN: For ampacity of fixture wire, maximum operating temperature, voltage limitations, minimum wire size, and so forth, see Article 402.







    310.10 Temperature Limition of Condutors. No conductor shall be used in such a manner that its operating temperature exceeds that designated for the type of insulated conductor involved. In no case shall conductors be associated together in such a way, with respect to type of circuit, the wiring method employed, or the number of conductors, that the limiting temperature of any conductor is exceeded.
    The surface of a FA heating duct, uninsulated, and without a thermal break between it and the metalic outlet box screwed thereto (and without a gasket for air leakage) IMO is an "environment" which exceeds 86F ambient, further the "heat" from continuous operation of incandenscent luminaire would likely exceed even if not operatied. Ask yourself what is the temperature of the heated FA via the duct so near the source (HE)? 160 F? 140 F? 135F?. Further, sheet metal without interior metal brace at point of contact would not be "surely" fastened so as to prevent movement, flex, etc. due to temperature changes. Next, could it be an outlet box supported by conduit or tubing, which then (the box) supports a lightweight luminaire....i.e. NO screws or attachment of the "box" to the duct, plenum, trunk, above..(but that's not what the Original Poster has indicated):
    Condensation, no gasket, isolator, protection or closure from attachment screws, entry of condensation (collecting on duct exterior) in unconditioned, uninsulated (masonry wall interior exposed, no insulation), apparent LAUNDRY AREA, indicated by dryer vent passing through block window, and suggested by plumbing upon the wall pictured beyond the luminaire.
    NEC has considered a laundry area in a dwelling, or residential, at a minimum a damp location regards safety of persons. It (laundry area outlet for washing machine) was the FIRST to REQUIRE a grounding type receptacle (IIRC two code cycles before) the use of grounding type receptacles were required elsewhere in residential construction. As an unfinished, non-habital, non-conditioned, non-insulated area of this basement - and apparently also a laundry area, I won't engage further on this issue with those known to ignore plain language defining such areas.
    A listed residential washer has a means to eject overflow path should compartment be overfilled, to the floor by design which protects internal wiring. As suggested by the presence of plumbing pictured on the wall - beyond the luminaire, it is further suggested that beneath same would be a likely path of a person to travel (on the floor) to get to the washing machine to disconnect it or turn it off, and to shut off the supply of water (should for example the float switch in the machine fail and over-fill the washing compartment). Hence the earlier curousity regarding the HEIGHT of the unguarded lamp, the luminaire, the outlet box to which it is mounted above the (finished or unfinshed) "floor" or walking surface - and its proximity horizontally to the "window" pictured (block or not is not specified).
    314.15 Damp or Wet Locations. In damp or wet locations, boxes, conduit bodies, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the bos, conduit body, or fitting. Boxes, conduit bodies, and fittings installed in wet locations shall be listed for use in wet locations.
    Collected condensation upon duct above and entry into box via "screws" attaching box to duct in "laundry area" or in "basement".
    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. Screws shall not be permitted to pass through the box unless exposed threads in the box are protected using approved means to avoid abrasion of conductor insulation.
    --(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 x 50 mm (1 in. x 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 fitings identified for the application.
    -(D) Suspended Ceilings. An enclosure mounted to structural or supporting elements of a suspended ceiling shall be not more than 1650 (cubic) cm (100 (cubic) in.) in size and shall be securely fastened in place in accordance with either (D)(1) or (D)(2).
    --(1) Framing Members. An enclosure shall be fastened to the framing members by mechanical means such as bolts, screws, or rivets, or by the use of clips or other securing means identified for use with the type of ceiling framing member(s) and enclsoure(s) employed. The framing members shall be adequately supported and securely fastened to each other and to the building structure.
    --(2) Support Wires. The installation shall comply with the provisiions of 3011(A). The enclosure shall be secured, wiring methods identified for the purpose, to ceiling support wire(s), including any additional suport wire(s) installed for that purpose. Support wire(s) used for enclosure support shall be fastened at each end so as to be taut within the ceiling cavity.
    -(E) Raceway Supported Enclosure, Without Devices, Luminaires, or Lampholders. An enclosure that does not contain a device(s) other than splicing devices or support a luminaire(s), lampholder, or other equipment and is supported by entering raceways shall not exceed 1650 cubic cm (100 cu. in.) in size. It shall have threaded entries or have holes identified for the purpose. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 900 mm (3 ft) of the enclosure, or within 450 mm (18 in.) of the enclosure if all conduit entries are on the same side.
    --Exception: Rigid metal, intermediate metal, or rigid non-metallic conduit or electrical metallic tubing shall be permitted to support a conduuit body of any size, including a conduit body constructed with only one conduit entry, provided the trade size of the conduit body is not larger than the largest trade size of the conduit or electrical metallic tubing.
    -(F) Raceway-Supported Enclosures, with Devices, Luminaires, or Lampholders. An enclosure that contains a device(s), other than splicing devices, or supports a luminaire(s), lampholder, or other equipment and is supported by entering raceways shall not exceed 150 cu. cm (100 cu. in) in size. It shall have threaded entries or have hubs identified for the purpose. It shall be supported by two or more conduits threaded wrenchtight into the enclosure or hubs. Each conduit shall be secured within 450 mm (18 in.) of the enclosure.
    --Exception No. 1: Rigid metal or intermediate metal conduit shall be permitted to support a conduit body of any size, including a conduit body constructed with only one conduit entry, provided the trade size of the conduit body is not larger than the largest trade size of the conduit.
    --Exception No. 2: An unbroken length(s) of rigid or intermediate metal conduit shall be permitted to support a box used for a luminaire or lampholder support, or to support a wiring enclsure that is an integral part of a luminaire and used in lieu of a box in accordance with 300.15(B), where all of the following conditions are met:
    ---(a) The conduit is securely fastened at a point so that the length of conduit beyond the last point of conduit support does not exceed 900 mm (3 ft).
    ---(b) The unbroken conduit length before the last point of conduit support is 300 mm (12 in.) or greater, and that the portion of the conduit is securely fastened at some point not less than 300 mm (12 in.) from its last point of support.
    ---(c) Where accessible to unqualified persons, the luminaire or lampholder, measured to its lowest point, is at least 2.5 m (8 ft) above grade or standing area and at least 900 mm (3 ft) measured horizontally to the 2.5 m (8 ft) elevation from windows, doors, porches, fire escapes, or similar locations.
    ---(d) A luminaire supported by a single conduit does not exceed 300 (12 inc.) in any direction from the point of conduit entry.
    (e) The weight supported by any single conduit does not exceed 9 kg (20 lb).
    ---(f) At the luminaire or lampholder end, the conduit(s) is threaded wrenchtight into the box, conduit body, or integral wiring enclosure, or into hubs identified for the purpose. Where a box or conduit body is used for support, the luminaire shall be secured directly to the box or conduit body, or though a threaded conduit nipple not over 75 mm (3 in.) long.

    -(G) Enclousres in Concrete or Masonry. An enclousre supported by embedment shall be identified as suitably protected from corrosion and securely embedded in concrete or masonry.
    -(H) Pendant Boxes. An enclosure supported by a pendant shall comply with 314.23(H)(1) or (H)(2).
    --(1) Flexible Cord. A box shall be supported from a multiconductor cord o cable in an approved manner that protects the conductors against strain, such as a strain-relief connector threaded into a box with a hub.
    --(2) Conduit. A box supporting lampholders or luminaires, or wiring enclosures within luminaires used in liew of boxes in accordance with 300.15(B), shall be supported by rigid or intermediate metal conduit stems. For stems longer than 450 mm (18 in.), the stems shall be connected to the wiring system with flexible fittings suitable for the locatin. At the luminaire end, the conduit(s) shall be threaded wrenchtight into the box or wiring enclosure, or into hubs identified for the purpose.
    Where supported only by a single conduit, the threaded joints shall be prevented from loosening by the use of set-screws or other effective means, or the luminaire, at any point, shall be at least 2.5 m (8 ft) above grade or standing area and at least 900 mm (3 ft) measured horizontally to the 2.5 m (8 ft) elevation from windows, doors, porches, fire escapes, or similar locations. A luminaire supported by a single conduit shall not exceed 300 mm (12 in.) in any horizontal direction from the point of conduit entry.

    314.27 Outlet Boxes.

    -(A) Boxes at Luminaire Outlets. Boxes used at luminaire or lampholder outlets in a ceiling shall be designed for the purpose and shall be required to support a luminaire weighing a minimum of 23 kg (50 lb). Boxes used at luminaire or lampholder outlets in a wall shall be designed for the purpose and shall be marked on the interior of the box to indicate the maximum weight of the luminaire that is permitted to be supported by the box in the wall, if other than 23 kg (50 lb). At every outlet used exclusively for lighting, the box shall be designed or installed so that a luminaire may be attached.
    --Exception: A wall-mounted luminaire weighing not more than 3 kg (6 lb) shall be permiteed to be supported on other boxes or plaster rings that are secured to other boxes, provided the luminaire or its supporting yoke is secured to the box with no fewer than two No. 6 or larger screws.
    -(B) Maximum Luminaire Weight. Outlet boxes or fittings designed for the support of luminaires and installed as required by 314.23 shall be permitted to support a luminare weighing 23 kg (50 lb) or less. A luminaire that weights more than 23 kg (50 lb) shall be supported independently of the outlet box unless the outlet box is listed and marked for the maximum weight to be supported.


    Bottom Line, Surface mounted but raceway supported 314.23(F) still has to meet all criteria, including above walk surface and away from window, and the general provisions for the conditions, including temperature environment - heat duct trunk without thermal break and not rigid and without gasket or sealing exposes box, conductors, luminaire wiring, luminaire itself to higher temperatures, ambient so as not to accomodate operating temperatures, and proximity to floor - and environment of installation (laundry area, unfinished, occupiable, not habital, unfinished basement) and subject to condensation, etc. So, and without proof that metal support interior to the duct which provides rigidity and support at connection point - I'd say NOPE, until proven otherwise. Now, if the duct is purely for AC - still NO - without sealing/gasket from screws connecting box to sheet metal above - subject to condensation entry into box via screw threads - and condensation collection on exterior of box entering luminaire. No guard for lamp either - hazard. BTW looks like vibration or otherwise (duct flex due to temps?) has caused the lamp to fail - appears "burnt out". :P








    There is so much posted here that does not apply it is almost painful.

    As shown this is not a raceway supported fixture or enclosure so you can leave out all the extraneous clearence requirements, the need for threaded hubs etc that have been added to this discussion.

    This is either a plastic or porcelain fixture that does not need grounding as it does not have exposed conductive parts.

    All answers based on unamended National Electrical codes.

  15. #15
    Join Date
    Mar 2007
    Location
    Ormond Beach, Florida
    Posts
    26,252

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by Jim Port View Post
    There is so much posted here that does not apply it is almost painful.
    Actually, there is a lot there which DOES apply to that luminaire and its support and mounting.

    I posted the code section I did as it was most applicable, H. G. posted other code sections which are also applicable. H. G. was, in his normal way, overbearing and over informative, along with other things, but much of the information was applicable.

    This is either a plastic or porcelain fixture that does not need grounding as it does not have exposed conductive parts.
    The box and the raceway require bonding.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  16. #16
    Join Date
    Aug 2008
    Location
    Maryland
    Posts
    1,899

    Default Re: Light fixture on metal heating duct.

    Quote Originally Posted by Jerry Peck View Post
    The box and the raceway require bonding.
    Agreed. I was referring to this section that was not needed in regards to this particular fixture.
    410.40 General. Luminaires and lighting equipment shall be grounded as required in Article 250 and Part V of this article.


    410.42 Exposed Luminaire.
    -(A) Exposed Conductive Parts. Exposed metal parts shall be connected to an equipment grounding conductor or insulated from the equipment grounding conductor and other conducting surfaces or be inacessible to unqualified personnel. Lamp tie wiries, mounting screws, clips, and decorative bands on glass spaced at least 38 mm (1-1/2 in.) from lamp terminals shall not be required to be grounded.
    -(B) Made of insulating Material. Luminaires directly wired or attached to outlets suppied by a wiring method that does not provide a ready means for grounding attachment to an equipment grounding conductor shall be made of insulating material and shall have no exposed conductive parts.
    --Exception No. 1: Replacement luminaires shall be permitted to connect to an equipment grounding conductor from the outlet in compliance with 250.130(C). The luminaire shall then comply with 410.42(A).
    --Exception No. 2: Where no equipment grounding conductor exists at the outlet, replacement luminaires that are GFCI protected shall not be required to be connected to an equipment grounding conductor.


    410.44 Equipment Grounding Conductor Attachment. Luminaires with exposed metal parts shall be provided with a means for connecting an equipment grounding conductor for such luminaires.


    410.46 Methods of Grounding. Lumianires and equipment shall be mechanically connected to an equipment grounding conductor as specified in 250.118 and sized in accordance with 250.122.
    Adding the part about the enclosure or raceway supported fixture could serve to confuse someone that does not know that those conditions do not apply in this case. They could later try to impose those restrictions unnecessararily if they did not make the distinction.

    All answers based on unamended National Electrical codes.

  17. #17
    John Steinke's Avatar
    John Steinke Guest

    Default Re: Light fixture on metal heating duct.

    A good point was made in asking 'how are the wires getting to the box?' Wiring within a duct is a problem.

    As I see it, the box is 'surface mounted.'


  18. #18
    Join Date
    Feb 2011
    Location
    Ohio
    Posts
    73

    Default Re: Light fixture on metal heating duct.

    Wow,
    BTW. Its is right above a laundry, conductors in metal conduit, no bonding.

    You guys really debate. I love seeing the codes that apply, but I like even more, the "bottom line overview". Thanks. It helps us common folk understand if it's "OK or Not", "Minor or Major". That's what we need.

    Thanks for everyones response!!


Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •