NEC 410.66 - Thermal insulation around light fixture

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steve66

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Per 410.66(B):

Thermal insulation shall not be installed above a recessed luminaire or within 3" of the luminaire's enclosure....

Can I place a drywall box around the fixture and lay insulation on top of the box if I keep enough clearance? How much clearance would be required?

If you take this phrase literally, you couldn't install insulation on the 13th floor if it is above a fixture on the 1st floor!!

Steve
 
Re: NEC 410.66 - Thermal insulation around light fixture

Most jurisdictions (enforcing the energy codes) require the 'sheet-rock' box enclosure around the NON-IC cans...maintaining the 3" clearances in doing so...then insulating on and around this box. If your can is IC rated, then the insulation goes directly on/over these cans.
 
Re: NEC 410.66 - Thermal insulation around light fixture

Check with the AHJ, in Oregon in cavities intended to be insulated only IC rated cans can be installed.

tom-inspector
 
Re: NEC 410.66 - Thermal insulation around light fixture

I once had a lighting rep tell me that he'd slap any sticker I needed on his luminaires. Need a luminaire with an IC rating, he'd slap it on. I washed my hands after he left and still felt dirty. :( Still don't spec around his company and he's no longer my rep.
 
Re: NEC 410.66 - Thermal insulation around light fixture

Actually, this is a lay-in 2x4 troffer as opposed to a can light.

So if I specify a drywall box to maintain 3" around the fixture, the insulation can then be laid over and wrapped around the box?

Steve
 
Re: NEC 410.66 - Thermal insulation around light fixture

I just checked out Lithonia and they have an option ("FR" I think) so that the luminaire can be installed in an insulated ceiling. Might be worth a call to your lighting rep and see if they have an option that can be added to cat. no. such that the luminaire is IC rated. Save you some time boxing out luminaires. I assume this is a static troffer, correct?
 
Re: NEC 410.66 - Thermal insulation around light fixture

I've seen this Lithonia Type IC troffer in the field, so they are available. Works great where the fixture is tight up against insulated ductwork.
 
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