1. The maximum common sizes (by wattage)
Downlight cutouts are usually related to their power. For small three-5W downlights (exceptional for shelves or hallways), the hollow length is usually 70-90mm in diameter. Medium 7-12W ones (perfect for residing rooms) want ninety-120mm holes. large 15-20W downlights (used in kitchens or huge rooms) require a hundred and twenty-150mm. think of it like footwear: bigger "strength" wishes a larger "footprint"!
2. Why length topics (it’s not just random)
A too-small hollow will overwhelm the light’s body; too huge and the downlight will wobble like a unfastened teeth. most manufacturers list the exact cutout size at the box—look for "cutout diameter" or "set up hole size." if you’re buying on line, check the specifications! Mismatched sizes imply extra work (like enlarging the hollow) or a messy-searching ceiling.
3. unique instances to notice
narrow downlights (the ones flat, cutting-edge ones) often need smaller holes—every now and then as tiny as 50mm. Adjustable angle downlights (that swivel) would possibly need 5-10mm extra area than their constant opposite numbers. And recessed downlights for wet areas (like lavatories) commonly require a good 100-120mm cutout to in shape their casing.
4. quick pointers for measuring & cutting
Use a tape degree to test the ceiling thickness first—you want sufficient space above for the light’s frame. Mark the middle with a pencil, then use a hollow noticed (the tool looks like a round blade) matching your wished length. start sluggish whilst slicing to avoid splintering the ceiling. in case you’re unsure, purchase the downlight first, then healthy the hollow to its specifications—it’s like tailoring clothes to in shape!
