flouresent fixtures to ceiling wires

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mjc

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Hi guys,
a partner and I were installing 2x4 (277v) florescent fixtures today. The specs require that they be supported by the ceiling grid , screwed to the grid , and additional ceiling wires be installed at opposite corners of the fixture. (additional ceiling wire to be provided and installed by the electrical contractor)My partner was saying that its an part of the NEC that these wires be attached to the fixture.
If so where in the NEC does it say this?

Thanks -- Mike :confused:
 
Re: flouresent fixtures to ceiling wires

It doesn't say this, all that is required is covered in 410.16. If you do use additional tie wires see 300.11.

Roger
 
Re: flouresent fixtures to ceiling wires

Building codes, not the NEC will require that the fixtures be independently supported with hanger wires, jack chain, etc. in two oposite corners or all four corners.

-Hal
 
Re: flouresent fixtures to ceiling wires

I believe that 410.16(C) is the section that applies to your situation as Roger pointed out. Some 2 x 4 drop-ins have a small clip or tab on each corner that you bend outward so that it rests on top of the ceiling grid and prevents the fixture from movement and falling through the grid.

If your specs indicate that you are required to further support the fixture by support wires I would suggest that you identify them for the use intended. I know some electricians that use the same support wires that hold up the grid but they spray paint them OSHA orange before attaching them to the fixture and building member.
 
Re: flouresent fixtures to ceiling wires

In Mass we have an ammendment that requires us to tie up the fixtures as you describe.

It is incase there is a fire so that the ceiling can be torn down without the fixtures falling on them.

I would recommend #12 tie wire. The kind that is used to hold the ceiling up in a commercial building. Jack chain is a real pain and time consuming. The chain gets caught on "everything" while you are trying to install it.

Are you tying them up to Bar joists or do you have to install clips or screws? If Bar joists I can give you a nice time saving tip.
 
Re: flouresent fixtures to ceiling wires

Job specs can and often do go beyond code, what would be the point if they did not.

We did a 6 story office building in RI, all 2' x 2' parabolic drop in fixtures.

Job specs.

Screw each fixture to the grid in each corner.

Install 4 - #12 steel support wires from each corner up to separate supports in the cement deck.

I think we burned up two "Vipers" (A Ramset on a pole)

I could sit on these fixtures. :roll:

[ April 24, 2004, 03:47 PM: Message edited by: iwire ]
 
Re: flouresent fixtures to ceiling wires

Hi all , thanks for the reply !! :D
Didn't think there was such a thing in the NEC ,but it sure got my attention , kept thinking I was missing somthing.

rhombus65 --- We are not tying them to bar joists , but shooting them into a concrete floor above the drop ceiling with pins. I would appreciate Knowing the time saver anyway it may be used one of these days.
Mike, Detroit ,MI
 
Re: flouresent fixtures to ceiling wires

In a lot of jurisdictions, seismic requirements mandate how to support fixtures. These seismic requirements may be part of the Building Code or there may be some special codes to consider.
 
Re: flouresent fixtures to ceiling wires

The building code is the right place to look. 1997 UBC section 25.213 requires the additional support. Also ASTM writes many standards for installation and they call for support wires whenever the ceiling system is not designed to additional weight (very few ceiling systems are actually designed for ANY additional weight).

Support clips are also required but that is a part of the NEC.
 
Re: flouresent fixtures to ceiling wires

In our area (Northern Ilinois) we have to support on two opposite corners. We just cut a deal with the ceiling installers and they put up all of the anchors and support wire for us. We just drop the fixture in and twist the wire on.
 
Re: flouresent fixtures to ceiling wires

Originally posted by ryan_618:
2000 IBC 1621.2.5 says they need thier own wires. :)
Click to expand...
And the 2003 IBC simply referes to ASCE 7, which I haven't read yet (still waiting for our copy). But I understand the requirement hasn't changed from what is required in the 2000 IBC.
 
Re: flouresent fixtures to ceiling wires

Hi Ed. From what I understand (talking to gilbert from Murray City), the ASCE 7 is basically the 2000 IBC 1621.2.5+the CISCA 3-4 all rolled into one. So your right, nothing changed, except for we have to buy another book :D
 
Re: flouresent fixtures to ceiling wires

Tie off opposite corners to red iron with ceiling wire and screw each end here.
 
Re: flouresent fixtures to ceiling wires

I'm currently building an ITT Tech Center, and yes we have to install "siesmic" wires to the opposite corners of the fixture. I understand why, but why do we also screw the fixture to the grid? The clips on the fixtures sides (hurricane clips) I can see using. They will easily come loose when the grid is pulled down. But screws?????
 
Re: flouresent fixtures to ceiling wires

The UBC requires: All lighting fixtures shall be positively attached to the suspended ceiling system. The attachment device shall have a capacity of 100% of the lighting fixture weight acting in any direction. from UBC Std 25.213

The NEC requires: Fixtures to 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 fixture(s)shall also be permitted. from 1999NEC 410-16(c)

The UL guide IEVV for recessed fixtures:
Recessed luminaires intended for use in suspended ceilings and provided with integral clips are marked for use with particular grid systems. When installed in accordance with this marking they comply with 410-16(c) of the NEC. Instructions for using clips to secure the luminaire to the grid are provided with the luminaire. The ability of these clips to withstand seismic disturbances has not been evaluated.

In an email I received from an engineer at UL (John Taecker) he indicated that fixtures are inverted with clips attached to fixtures and framing members.

So, is there any point to this rambling?

Both codes want the fixtures and grid to NOT come apart.
Most contractors do not specifically order fixtures compatible with grid systems(I haven't seen one yet)so the fixture clips are not identified for the grid. Everyone here just uses screws cause it's simpler and also it's been done this way for 20 years. It seems we are creatures of habit.
 
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