IC-rated downlight

An IC-rated downlight is a downlight rated for insulation contact (IC), so ceiling batts can be laid right over it without a clearance gap or a fire risk. It is the alternative to building a clear zone (typically around 50 to 200 mm) around a non-IC fitting and cutting a hole in the insulation.

The issue IC ratings solve is heat. An older or non-IC downlight runs hot, so covering it with insulation traps that heat and is a genuine fire risk. The wiring rules and the fitting’s instructions then require insulation (and sometimes combustible material) to be kept clear of it, which means a gap around every fitting. Each gap is a hole in the ceiling insulation, and a ceiling full of downlights with clearance zones can lose a large share of its insulation value through those holes, undoing the thermal performance the rating assumed.

An IC-rated fitting (you will also see IC-4, meaning it can be both insulation-covered and abutted) is built to run cool enough that batts can sit hard against and over it. That keeps the insulation continuous and removes the clearance requirement.

For a builder the practical points are to specify IC-rated (ideally IC-4) downlights wherever they sit in an insulated ceiling, so the insulation stays continuous and the energy rating is actually achieved on site, and to make sure the insulation is then installed over them rather than cut around them. If non-IC fittings are used, the required clearances must be maintained, but the better answer on a new build chasing a star rating is simply to use IC-rated fittings and keep the blanket unbroken.

Also known as: IC downlight, IC-4 downlight, insulation-contact luminaire.

Category: Electrical / Insulation.

Related

• AS 3999 bulk insulation
• Bulk insulation

See also

• Thermal performance

References

• AS/NZS 3000 Wiring Rules, Standards Australia (verified 2026-06-01)

---

Last updated: 2026-06-01. Verified: 2026-06-01. Quarterly review for currency.