2x4 Lay-in

[jmsbrush]

Good morning guys, when installing a 2x4 lay-in fixture. Does the NEC required you to have 2 or 4 corners strapped by tie wires?

 

[jumper]

Depends,

NEC 410.36(B) says ceiling can support fixtures, but many building codes in seismic areas says you need independent support.

 

[Dennis Alwon]

Good morning guys, when installing a 2x4 lay-in fixture. Does the NEC required you to have 2 or 4 corners strapped by tie wires?

I don't believe that is an NEC req. but rather a building requirement. I do 2 sides in the middle on the long dimension. The recessed fixtures I use have a hole designed just for that.

 

[sparky=t]

building code here requires opposing corners have independent support from the structure when installed in a suspended accoustical ceiling.

 

[jmsbrush]

I just called the inspector for this area and he told me what they look for is this: Who is the manufacture of the ceiling grid and what is required by them?
He said some grids don't require any tye wire for the fixtures. He said to be safe, they typically look for two wires on opposite corners.

 

[jmsbrush]

Thank you guys for your help, do you guys feel like it should be a NEC requirement to use tye wire on lay-in's?

 

[Split Bolt]

Here, it varies with the jurisdictions. It should be a building and fire code rule, not in the NEC, IMHO, like smoke detector requirements. I could never understand why some jurisdictions used to require them to be screwed to the grid. A fire marshal once told me that the purpose of tying them up independent of the ceiling was so that, during a fire, they can tear the ceiling down without having the lights fall on them. Makes sense to me!

 

[roger]

Thank you guys for your help, do you guys feel like it should be a NEC requirement to use tye wire on lay-in's?

I don't.

Roger

 

[jmsbrush]

Here, it varies with the jurisdictions. It should be a building and fire code rule, not in the NEC, IMHO, like smoke detector requirements. I could never understand why some jurisdictions used to require them to be screwed to the grid. A fire marshal once told me that the purpose of tying them up independent of the ceiling was so that, during a fire, they can tear the ceiling down without having the lights fall on them. Makes sense to me!

That makes sense to me as well.

 

[LarryFine]

I've never had an issue when I use the built-in fold-out grid clips.

 

[jumper]

A fire marshal once told me that the purpose of tying them up independent of the ceiling was so that, during a fire, they can tear the ceiling down without having the lights fall on them. Makes sense to me!

While the fire idea seems good, I do not think that is it. Otherwise it would be required everywhere.

I was told it was a building code in seismic zones, so the support might help prevent the fixtures falling down in a quake.

 

[teco]

Here, it varies with the jurisdictions. It should be a building and fire code rule, not in the NEC, IMHO, like smoke detector requirements. I could never understand why some jurisdictions used to require them to be screwed to the grid. A fire marshal once told me that the purpose of tying them up independent of the ceiling was so that, during a fire, they can tear the ceiling down without having the lights fall on them. Makes sense to me!

That is exactly what I've been told by building inspectors and the fire dept from many different towns here in Ma.

 

[macmikeman]

From the insurance reports I have read, lay in lights tend to fall in an arc motion because of the whip attachment, and accelerate in an an arcing motion like a baseball bat does. This can be quite lethal. That is why the code itself wants the fixture to be locked into the grid. The locl building codes (if) cover the independent support wires. Not required here, but it's not such a bad idea to secure them anyway.

 

[jmsbrush]

I can remember some jobs when I was an employee, that the boss made us use self tappers, drilling though the grid into the fixture.

 

[acrwc10]

While the fire idea seems good, I do not think that is it. Otherwise it would be required everywhere.

I was told it was a building code in seismic zones, so the support might help prevent the fixtures falling down in a quake.

This is a great point to clear up. All area's are in a "seismic zone" they are classified from zone "A","B","C","D","E", and "F". Zone "A" being the lower end of the scale and "F" the highest magnitude zone.
Where I am is zone F and the requirement is two independent wires in opposing corners and 2 screws into the grid on the other corners. The 2 screws keep the fixture from coming out of the grid while the 2 wires carry the weight of the fixture.
What they discovered was so many things were being hung from the grid and the hanging wires for the grid, that the entire ceiling could come down because it was not engineered to hold all the additional weight. There is an extra heavy tee bar grid available but we still need to hang the fixtures independently. I recently watched a security camera recording during an earthquake and the 2x4 troffer came down and hit a person sitting below it, looked painful.

 

[jumper]

This is a great point to clear up. All area's are in a "seismic zone" they are classified from zone "A","B","C","D","E", and "F". Zone "A" being the lower end of the scale and "F" the highest magnitude zone.

IBC, right?

I recently watched a security camera recording during an earthquake and the 2x4 troffer came down and hit a person sitting below it, looked painful.

OUCH!!!

 

[acrwc10]

IBC, right?




OUCH!!!

Yup, Chapter 16