Recessed Luminaire Clearance Calculator
Check the clearances a recessed luminaire (can light) needs under National Electrical Code (NEC) 410.116: 1/2 in from combustible framing and 3 in from thermal insulation for a non-Type IC fixture, with no insulation above it. Pick the type, enter the measured clearances, and the tool returns a compliance verdict, or confirms a Type IC fixture may contact both.
How to use this calculator
- Select the luminaire type: non-Type IC (not marked for insulation contact) or Type IC. A fixture whose IC marking you cannot confirm is non-IC.
- For a non-IC fixture, enter the measured clearance from the recessed parts to the nearest combustible material to check it against the 1/2 in minimum.
- Answer whether thermal insulation is present, and if so whether it sits directly above the luminaire. Insulation above a non-IC fixture is prohibited.
- If insulation is present but not above, enter its clearance to the enclosure to check it against the 3 in minimum.
- Read the verdict: compliant, not met, or (for Type IC) contact permitted. A Type IC fixture needs no clearance from combustibles or insulation.
NEC reference
This calculator implements NEC 2020 410.116, Clearance and Installation for recessed luminaires: 410.116(A)(1) spaces all recessed parts of a non-Type IC luminaire not less than 1/2 in (13 mm) from combustible materials (the points of support and the finish trim at the opening may contact combustibles); 410.116(A)(2) permits a Type IC luminaire to contact combustibles; and 410.116(B) prohibits thermal insulation above a recessed luminaire or within 3 in (75 mm) of its enclosure, wiring compartment, ballast, transformer, LED driver, or power supply, unless the luminaire is identified as Type IC.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.
Clearances at a glance
410.116 sets two fixed clearances for a recessed luminaire, and the type of the fixture decides whether they apply. A non-Type IC fixture keeps its distance from framing and insulation; a Type IC fixture, identified for the use, may touch both.
| Condition | Non-Type IC | Type IC | NEC |
|---|---|---|---|
| Recessed parts to combustible material | 1/2 in (13 mm) minimum | May contact | 410.116(A) |
| Thermal insulation beside the fixture | 3 in (75 mm) minimum | May contact | 410.116(B) |
| Thermal insulation above the fixture | Not permitted | Permitted | 410.116(B) |
| Points of support and finish trim at the opening | May contact combustibles | May contact | 410.116(A) |
Two different clearances, two different reasons
The 1/2 in combustible clearance in 410.116(A)(1) keeps the hot housing off the wood it is framed into. The 3 in insulation clearance in 410.116(B) keeps batt or blown insulation from trapping heat around the enclosure and driver, which is a fire risk and shortens the life of the electronics. They are measured to different things, the framing versus the insulation, so a fixture can pass one and fail the other. The 1/2 in rule is forgiving at the trim, where contact is allowed; the 3 in rule is absolute above the fixture, where no insulation is permitted on a non-IC luminaire at any distance.
Type IC is the way out of both clearances
A luminaire identified as Type IC (insulation contact) is built and tested to run buried in insulation, so 410.116(A)(2) lets it contact combustibles and 410.116(B) lets insulation cover it. In an insulated ceiling, such as the top floor under a vented attic, a Type IC fixture is usually the only practical choice, because keeping blown insulation 3 in clear of a non-IC can in every direction, and off the top entirely, is not realistic. The allowance depends on the actual marking: a fixture that is not clearly labeled Type IC must be treated as non-IC, which is why this tool defaults to the strict branch.
Worked example: a can in an insulated ceiling
A non-IC recessed can sits in a ceiling with its housing 3/4 in from the nearest joist and blown insulation pushed up against the back of the fixture. The 3/4 in to the joist clears the 1/2 in combustible minimum, 410.116(A)(1). But the insulation against and over the housing fails 410.116(B): on a non-IC fixture, insulation may be neither above it nor within 3 in. The fix is to dam the insulation back 3 in and keep it off the top, or to swap in a Type IC fixture, after which insulation may contact it freely.
Common mistakes
- Assuming any LED can light is IC-rated. The allowance is tied to the Type IC marking, not the lamp technology. Confirm the label before letting insulation touch the fixture.
- Treating the 3 in rule as only horizontal. 410.116(B) also forbids insulation above a non-IC luminaire outright, not just within 3 in to the side.
- Measuring the combustible clearance to the trim. The 1/2 in is to the recessed parts; the trim and points of support at the opening are allowed to contact combustibles.
- Confusing IC with airtight. Airtight (ICAT) is an energy-code and air-barrier concern. A fixture can be IC without being airtight; 410.116 is about heat near combustibles and insulation.
- Forgetting the enclosure includes the driver. The 3 in is measured to the enclosure, wiring compartment, ballast, transformer, LED driver, or power supply, whichever is closest to the insulation.
Frequently asked questions
How much clearance does a recessed light need from insulation?
For a non-Type IC luminaire, insulation must stay 3 in (75 mm) from the enclosure and driver and must not be installed above the fixture, per 410.116(B). A Type IC luminaire may contact insulation.
What is the clearance from combustibles?
410.116(A)(1) requires the recessed parts of a non-IC luminaire to be at least 1/2 in (13 mm) from combustible materials. The points of support and the finish trim at the opening may contact combustibles. A Type IC fixture may contact combustibles at its recessed parts.
Can I bury a recessed light in attic insulation?
Only if it is marked Type IC. A non-IC fixture in an insulated attic ceiling must have the insulation dammed back 3 in and kept off the top; otherwise use a Type IC fixture, which is listed to be covered.
Does the finish trim have to clear the framing?
No. 410.116(A)(1) specifically permits the points of support and the finish trim at the ceiling or wall opening to be in contact with combustible materials. Only the recessed parts need the 1/2 in clearance.
Does this use the 2020 or 2023 NEC?
This tool uses the NEC 2020 text of 410.116. The 1/2 in and 3 in clearances and the Type IC contact allowance have been stable across recent editions; always verify against the edition your jurisdiction has adopted.
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