A recessed luminaire sits in the ceiling with its body in the roof space. It must shed its heat, and insulation around it can trap that heat. AS/NZS 3000 sorts recessed luminaires into classes by how they cope with insulation. This page explains the classes and the rules around them.
The classes
Table 4.3 sets out each class. In short:
| Class | Insulation may abut | Insulation may cover | Side and top surface limit |
|---|---|---|---|
| Non-IC | No | No | No limit, mounting surface 90 °C |
| Do-not-cover | No | No | No limit, mounting surface 90 °C |
| CA90 | Yes | No | 90 °C |
| CA135 | Yes | No | 135 °C, mounting surface 90 °C |
| IC | Yes | Yes | 90 °C |
| IC-4 | Yes | Yes | 90 °C |
- Non-IC is for buildings where insulation is not, and will not be, present.
- Do-not-cover may be used where insulation is present, but kept clear of it.
- CA90 and CA135 may have insulation against the sides, never over the top. CA135 runs hotter, so the materials touching it must be rated for that heat. CA135 is a New Zealand class.
- IC may be covered, and lets some air pass between the room and the roof space.
- IC-4 may be covered and is close to sealed, so little air passes. It suits an airtight house.
Which classes a home may have
Cl 4.5.2.3.5 lists them by country:
| Installation | New Zealand | Australia |
|---|---|---|
| Residential | CA90, CA135, IC, IC-4 | Do-not-cover, CA90, IC, IC-4 |
| Non-residential | All six | All but CA135 |
CA135 is not allowed anywhere in Australia. A Do-not-cover luminaire is not allowed in a New Zealand home.
Luminaires marked under the 2001 edition of the luminaire standard may be treated as the new classes: CA 80 as CA90, CA 135 as CA135, IC as IC, and IC-F as IC-4.
A luminaire with no marking
In New Zealand an unmarked fitting is treated as Do-not-cover (Cl 4.5.2.3.3(a)(ii)). It then needs barriers or clearances, and Do-not-cover is not on the list for a home. In practice, replace it.
The default clearances
Where the maker gives no clearances, Figure 4.9 sets defaults for a lamp up to 100 W. The tool reads which dimensions apply to each class from the drawing:
| Dimension | Value | Read for |
|---|---|---|
| HCB, height clearance to the building above | 100 mm | CA, Do-not-cover and Non-IC |
| SCB, side clearance to building elements | 100 mm | Do-not-cover and Non-IC |
| SCI, side clearance to insulation | 100 mm | Do-not-cover and Non-IC |
| SCG, side clearance to the control gear | 50 mm | Every class |
Open a CA90 with insulation against its sides.
Cl 4.5.2.3.3 adds three points that matter on site:
- (iv) Unless the maker or a classified barrier allows it, the space above the luminaire (HCB) stays clear of insulation.
- (v) Where clearances are used and the insulation is loose, a barrier or guard is fixed to keep them.
- (viii) Above 100 W, only a certified luminaire or the maker's clearances may be used. The defaults and a barrier alone do not apply.
The warning sign
Where recessed luminaires sit in an accessible roof space, a warning sign goes at the access point (Cl 4.5.2.3.2). It is not needed when every recessed luminaire in the space is IC or IC-4.
Check a downlight with the downlight clearance checker. Cables buried in insulation carry less current: check them with the correction factors tool. A worked ceiling is in Downlights in an insulated ceiling.