Downlight clearance check
IC, CA90 or Non-IC: may insulation touch the light?
Reads AS/NZS 3000:2018. Tables checked 1 Oct 2026.
Try a job 4
Each job fills in example values. Replace them with your values.
- Check a CA90 downlight against insulationA CA90 light with insulation against its sides, and its clearances.
- Read an old IC-F downlightAn IC-F marking read as IC-4 under insulation.
- Check a CA135 downlight in AustraliaA CA135 light in an Australian home.
- Check a Non-IC light in a shopA 50 W Non-IC downlight with insulation kept clear.
Inputs
Worked example with the default inputs. The live calculator replaces it when the page loads.
- Country
- New Zealand
- Installation
- Residential
- Marking on the luminaire
- IC-4
- Lamp rating
- 10 W
- Ceiling insulation
- Insulation over the top
- In an accessible roof space
- Yes
This luminaire here
Permitted
- Insulation may abut it
- Yes
- Insulation may cover it
- Yes
- Side and top surface limit
- 90°C
- Roof space warning sign
- Not required
This result is a design aid. Verify it against the current standard.
Calculation steps
- ClassIC-4
AS/NZS 3000:2018 Table 4.3
- Allowed in this installationYes
AS/NZS 3000:2018 Cl 4.5.2.3.5(b)(i)
- Insulation may abut itYes
AS/NZS 3000:2018 Table 4.3
- Insulation may cover itYes
AS/NZS 3000:2018 Table 4.3
- Side and top surface limit90°C
AS/NZS 3000:2018 Table 4.3
- Roof space warning signNot required
AS/NZS 3000:2018 Cl 4.5.2.3.2
About this calculator
How this is calculated
A recessed luminaire, usually a downlight, sits in the ceiling with its body in the roof space. Its heat has to go somewhere, so AS/NZS 3000 sets which classes may go where and how close insulation may come. The class is the symbol on the luminaire or its box.
The tool first reads the marking. A luminaire marked to the 2001 standard is read as its current class: an IC-F as IC-4, a CA 80 as CA90. Then it checks the class against the list for your country and installation. A New Zealand home may take CA90, CA135, IC and IC-4. An Australian home may take Do-not-cover, CA90, IC and IC-4. Other buildings add Non-IC and Do-not-cover, and New Zealand adds CA135.
Next it checks the insulation you plan against the class. IC and IC-4 may be covered. CA90 and CA135 may have insulation against their sides but not over the top. Do-not-cover may be near insulation but not touch it. Non-IC is not tested with insulation, so the tool warns when insulation is present even kept clear.
Where insulation is kept clear and the maker gives no distance, the tool gives the default clearances of the standard for a lamp up to 100 W, for the dimensions its drawing shows for the class. Above 100 W there are no defaults: use the maker's distances or a luminaire certified for the condition. Last, it says whether the roof space needs the warning sign.
| Step | Table or clause | What it decides |
|---|---|---|
| A 2001 marking | Cl 4.5.2.3.5 Exception | The class an old marking is read as |
| The class for this installation | Cl 4.5.2.3.5 | Whether the class may go in this home or building |
| Insulation against or over the luminaire | Table 4.3 | Whether insulation may abut or cover the class |
| Default clearances | Figure 4.9 | The distances where the clearance method is used |
| A lamp over 100 W | Cl 4.5.2.3.3(a)(viii) | Which methods remain |
| The roof space sign | Cl 4.5.2.3.2 | Whether the warning sign is needed |
Worked examples
- A CA90 downlight with insulation against its sides. The luminaire is Permitted in a New Zealand home. Insulation may abut it but not cover it, the space above stays clear, and the roof space needs the sign.
- An old IC-F downlight under insulation. The marking reads as IC-4, so the luminaire is Permitted and may be covered. No sign is needed if every downlight in the space is IC or IC-4.
- A CA135 downlight in an Australian home. The luminaire is Not permitted and fails: CA135 is not on the Australian list for any installation.
- A 50 W Non-IC downlight in a shop. The luminaire is Permitted in a non-residential building. Insulation must stay clear by the default clearances, with a fixed guard where it is loose.
- A downlight with no marking. The luminaire is Not permitted and fails: with no class and no stated clearances, it should not be installed.
Limits
The tool reads the class and the clauses. It does not test a luminaire or check the maker's instructions, which take the place of the defaults. It does not size the lighting circuit or check its cable in the insulation; use the correction factors tool for a cable run in insulation. Spotlights that heat the surface they light follow Table 4.2, which the tool does not check.
See also: Downlights and insulation: IC-4, CA90 and Non-IC, Downlights in an insulated ceiling and Lighting lumen method.
Questions
Each answer describes what this tool calculates. The result is a design aid. Verify against the current standard.
Can insulation cover a downlight?
Only an IC or IC-4 downlight. Those are tested to be covered by building insulation. A CA90 or CA135 may have insulation against its sides but not over the top. Other classes need insulation kept clear.
What clearance does a downlight need from insulation?
Where the maker gives none, AS/NZS 3000 Figure 4.9 sets defaults for a lamp up to 100 W: 100 mm to insulation, 100 mm to building elements, 100 mm above and 50 mm to the control gear. Which apply depends on the class.
Which downlights can go in a New Zealand home?
CA90, CA135, IC and IC-4. Non-IC and Do-not-cover may not go in a New Zealand residential installation. In Australia, homes may take Do-not-cover, CA90, IC and IC-4, and no CA135.
My downlight says IC-F. What is it?
A marking from the 2001 standard. AS/NZS 3000 lets an IC-F downlight be treated as IC-4, and a CA 80 as CA90. The tool reads the old marking this way.
When does the roof space need a warning sign?
When recessed luminaires are in an accessible roof space, unless every one of them is IC or IC-4. The sign goes at the access point, where a person entering sees it.
Clauses and tables this tool reads
- AS/NZS 3000:2018 Cl 4.5.2.3.2Roof space warning sign
- AS/NZS 3000:2018 Cl 4.5.2.3.5Recessed luminaire classes by installation
- AS/NZS 3000:2018 Cl 4.5.2.3, Figure 4.9 and Table 4.3Recessed luminaire classes, where each may go, and the default clearances
Every clause and table, with how each was verified
Tables last checked on 1 Oct 2026.
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