300.11 securing and supporting

[stew]

310.11 A tells us we cannot use the grid or grid support wires for securing like a bat wing or a zip tie on mc. if the support wires actually support the fixture like a troffer it seems that then the wire can be used eh? or if an additional wire in addition the the corner wire supports were attached to the grid and also to the ceiling then that wire can be used. H aving a hard time understanding why the grid wires cant be use for this minimal weight but we can go ahead and install a spreader bar across the grid and put in a lumniare thru the ceiling tile. we then are allowed and required to support mc at 12 inches so we use the spreader bar for attachment. does not make much sense to me. In Wash we have a WAC reg that states that we can use the grid and or grid wires for support if not prohibited by article 300. well it is prohibited by 300 so why have a WAC rule that you cant use anyway??

 

[John Arendt]

From 2008 NEC 300.11 (A)
"(1) Fire-Rated Assemblies. Wiring located within the cavity of a fire-rated floor?ceiling or roof?ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided and shall be permitted to be attached to the assembly. Where independent support wires are used, they shall be distinguishable by color, tagging, or other effective means from those that are part of the fire-rated design.
Exception: The ceiling support system shall be permitted to support wiring and equipment that have been tested as part of the fire-rated assembly.
FPN: One method of determining fire rating is testing in accordance with NFPA 251-2006, Standard Methods of Tests of Fire Resistance of Building Construction and Materials.
(2) Non?Fire-Rated Assemblies. Wiring located within the cavity of a non?fire-rated floor?ceiling or roof?ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided and shall be permitted to be attached to the assembly.
Exception: The ceiling support system shall be permitted to support branch-circuit wiring and associated equipment where installed in accordance with the ceiling system manufacturer?s instructions."

IMHO, I can't remember the last time I saw Mfg Instr. for a ceiling, although I know they are around. Trade practice around here is to install additional support wires. Wires used can also be the support for fixtures. A 'clamp' made by Caddy used to be common for the sparky wires, it was Caddy yellow and clipped onto the grid serving for support and ID.

Your analogy is good...perhaps a submission for a change in 2011 NEC? BTW, there is a weight restriction on the fixture supported by the Caddy ceiling bar; and plan specs also come into consideration for this matter.

 

[BryanMD]

310.11 A tells us we cannot use the grid or grid support wires for securing like a bat wing or a zip tie on mc. if the support wires actually support the fixture like a troffer it seems that then the wire can be used eh? or if an additional wire in addition the the corner wire supports were attached to the grid and also to the ceiling then that wire can be used. H aving a hard time understanding why the grid wires cant be use for this minimal weight but we can go ahead and install a spreader bar across the grid and put in a lumniare thru the ceiling tile. we then are allowed and required to support mc at 12 inches so we use the spreader bar for attachment. does not make much sense to me. In Wash we have a WAC reg that states that we can use the grid and or grid wires for support if not prohibited by article 300. well it is prohibited by 300 so why have a WAC rule that you cant use anyway??

Is this like the WAC rule for installing disconnects on ballasts?
(sorry had to do it)

As to the spreader bar for the recep.etc IT also needs to be supported by wire as do recessed lights and everything else we install. The key is that we need to support OUR work from supports WE install (eg the corner supports) for that purpose and do it INDEPENDENT of whatever other supports may be in place for other purposes.

BTW the Hilti extended bang gun works great.

 

[e57]

The key is that we need to support OUR work from supports WE install (eg the corner supports) for that purpose and do it INDEPENDENT of whatever other supports may be in place for other purposes.

OR - mark out spots for the cieling guy to shoot wire FOR YOU.... (While he's at doing HIS....) :wink: Be sure to mark yours with some paint before he does - and be nice enough to do it prior so they can dry first.....

 

[BryanMD]

OR - mark out spots for the cieling guy to shoot wire FOR YOU.... (While he's at doing HIS....) :wink:

Do your ceiling guys still do that for you?

Was a time when they would do it as part of the contract even supplying their own wire and hdwr without even asking you would ask (for the extra 5 or 6 you always end up needing).

 

[e57]

Do your ceiling guys still do that for you?

Was a time when they would do it as part of the contract even supplying their own wire and hdwr without even asking you would ask (for the extra 5 or 6 you always end up needing).

Yep - in fact most OFFER it to the GC - for an up-charge of course. And the GC doesn't want them for himself - he wants it because it isn't in our contract for them to be provided - so they get laid out before they start, and often know where the lights are before we do - I just spot paint a few more locations that I'm going to need.... Contracting is about contracts...

 

[Pierre C Belarge]

Is this like the WAC rule for installing disconnects on ballasts?
(sorry had to do it)

As to the spreader bar for the recep.etc IT also needs to be supported by wire as do recessed lights and everything else we install. The key is that we need to support OUR work from supports WE install (eg the corner supports) for that purpose and do it INDEPENDENT of whatever other supports may be in place for other purposes.

BTW the Hilti extended bang gun works great.

Is this a local law? The NEC does not say this, and in NY, the Building Code does not say it either. So, in NY, one can follow 410.16(C) - which basically says that the fixture can be supported from the grid, provided the Manufacturer's instructions don't say you cannot do so.

 

[POWER_PIG]

Makes no sense to me, The grid is designed to hold a troffer but not the whips going to it? The 2008 code (maybe 2005 too not sure) allows fixture whips up to 6 foot in length with any strapping at all, cept for the connectors at the fixture. So it's legal to just flop the whips onto the grid between fixtures(within 6ft) but you can't use bat wings or zip ties to make a neater install.
I would like to know the reason.

 

[e57]

This is from the 02 code and commentary: Bold by me...

300.11 Securing and Supporting.
(A) Secured in Place. Raceways, cable assemblies, boxes, cabinets, and fittings shall be securely fastened in place. Support wires that do not provide secure support shall not be permitted as the sole support. Support wires and associated fittings that provide secure support and that are installed in addition to the ceiling grid support wires shall be permitted as the sole support. Where independent support wires are used, they shall be secured at both ends. Cables and raceways shall not be supported by ceiling grids.
(1) Fire-Rated Assemblies. Wiring located within the cavity of a fire-rated floor?ceiling or roof?ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided. Where independent support wires are used, they shall be distinguishable by color, tagging, or other effective means from those that are part of the fire-rated design.
Exception: The ceiling support system shall be permitted to support wiring and equipment that have been tested as part of the fire-rated assembly.
Wiring methods of any type and all luminaires are not allowed to be supported or secured to the support wires or T bars of a fire-rated ceiling assembly unless the assembly has been tested and listed for that use. If support wires are selected as the supporting means for the electrical system within the fire-rated ceiling cavity, they must be distinguishable from the ceiling support wires and they must be secured at both ends.
Generally, the rule for supporting electrical equipment is ?securely fastened in place.? This phrase means not only that vertical support for the weight of the equipment must be provided but also that the equipment must be secured to prevent horizontal movement or sway. The intention is to prevent the loss of grounding continuity provided by the raceway that could result from horizontal movement.
Sections 300.11(A)(1) and (A)(2) are quite similar. Unless the exceptions apply, these sections clearly prohibit all types of wiring from being attached in any way to the support wires of a ceiling assembly. Unless ceiling grids are part of the building structure, they, too, are prohibited from furnishing support for cables and raceways. However, if wiring and equipment are located within the ceiling cavity and rigidly supported independent of the ceiling, without the use of ceiling-type hanger wire, then the requirements of this section are met.
Refer to the appropriate wiring method article in Chapter 3 of the Code for cable and raceway supporting requirements. See 410.15(A) and 410.16 for the proper support of luminaires; 314.23 for the support of outlet boxes; and 725.6, 760.6, and 770.8 for various low-voltage fire alarm and optical fiber cable supports. See Chapter 8 for communications cable supports.
FPN:One method of determining fire rating is testing in accordance with NFPA 251-1999, Standard Methods of Tests of Fire Endurance of Building Construction and Materials.
(2) Non?Fire-Rated Assemblies. Wiring located within the cavity of a non?fire-rated floor?ceiling or roof?ceiling assembly shall not be secured to, or supported by, the ceiling assembly, including the ceiling support wires. An independent means of secure support shall be provided.
Exception: The ceiling support system shall be permitted to support branch-circuit wiring and associated equipment where installed in accordance with the ceiling system manufacturer?s instructions.

Pretty much says you cant use the ceiling or the wires supporting the ceiling. Why? The ceiling is a system and rated as such - if rated for fire or not - it was designed to hold a specific load in terms of weight. (Not to mention tweaking the ceiling* if applying KX's or 8's etc.) Sure it's not that much wieght at each support for a 12/2 MC - but say it was a #2/4 feeder, or collectively 50 runs of 12/3 on the ceiling system? That's not that uncommon - right? That's a LOT of weight. I'll bet a number of us would have a full on fit if the ceiling guy came by and supported a ceiling grid from say a trapeze of conduit, or supports for fixtures.... If you were there first - and I usually try to be... Bet the HVAC guys would get all bent up about the same.... Or the Plumbers.... Add that to be dependable in case of a fire or earthquake - who's gonna allow hangers on then?

*If using the ceiling for a number of cables, even one cable - it will unlevel the ceiling, or portions of it, if they were tightened properly in the first place. One KX - with a 12/3 on it may raise that area 1/4"-3/8" and be visible when finished.... Do that with a bunch of cables - bit messy...

 

[BryanMD]

Pretty much says you cant use the ceiling or the wires supporting the ceiling. Why?

My understanding of the why (here in the east I've done differently in other parts of the country) is based on fire situations when they want to pull down the ceiling tiles (and grid) but not have the fixtures falling on their heads or add 2000 feet of MC to the floor etc.

YMMV