Guide
Underwater Light Beam Angle Guide
Beam angle decides whether an underwater fitting makes a column of light, a wall wash or a glow. The documented models offer two angle sets; matching them to water geometry is the whole exercise.
The listed angle sets
| 10° / 20° / 30° | LX-UD005, LX-SC009, LX-UD-001A — the low-voltage submersibles |
|---|---|
| 15° / 25° / 45° | LX-BG84786 — the single-emitter AC220V model |
What the angles do in water
A 10° beam from a basin floor stays narrow for metres, which is how a fitting under a jet column lights the column rather than the basin: the water itself becomes the visible element. At 20°, the cone widens enough to model a small feature — a sculpture, a rockery edge — with light and shade. At 30°, adjacent fittings overlap into a field, which is the pool-wall case: even luminance along the wall and across the water surface, with no single fitting announcing itself. The wider 45° option on the LX-BG84786 serves shallow, wide water where the fitting sits close under the surface it lights. Refraction at the surface bends every beam, and aerated fountain water scatters it, so fountain work usually steps one angle wider than the still-water calculation suggests.
Spacing follows angle
On a wall or floor, spacing is set by overlap: at 30°, fittings can sit roughly a beam-diameter apart at the lit surface and still blend; at 10°, they are individual accents and spacing is a composition choice. The LX-SC009 in its three sizes is the natural wall-washing candidate, and the compact LX-UD-001A carries the accent role. The selection sequence as a whole is set out in how to choose LED underwater lights, and the parent range is LED underwater lights.
Confirm before ordering
State the lit surface, its distance from the fittings and the effect you want — column, feature or field — and confirm the beam angle variant for your configuration before ordering.
Worked example: one basin, three angles
A round fountain basin with a central jet, a ring of small side jets and a stone rim. The centre fitting takes the 10° beam: its job is the column, and nothing else in the basin should compete with it. The side jets take 20° fittings, wide enough to model each jet's fall without spilling onto the rim. The rim itself, if it is to glow, takes a 30° fitting washing the basin floor and the lower wall, binding the composition together. Three angles in one basin is not indecision — it is the basin's geometry read honestly, jet by jet. The same logic scales down to a two-fitting pond and up to a musical fountain with dozens of points.
Angle mistakes that survive commissioning
- One angle everywhere, chosen from a catalogue photograph rather than the water in front of you.
- Narrow beams on a wall that was meant to read as a field — the scalloped wall is the signature of this error.
- Wide beams under a tall jet, so the column's top third goes dark where the audience looks first.
- Forgetting that aerated water widens every beam in practice; step wider in fountains than the still-water sketch suggests.
Prove the angle on the water you have
Angles are chosen on paper but proven in the basin. Where the project allows it, run one fitting of the shortlisted model at the intended depth and look at the result at night, from the audience's position: a column that reads cleanly in still water may break up in aerated water, and a wall wash that blends on the drawing may show its seams against real stone. Record the chosen angle for each position in the project file, next to the model and control variant, so that a replacement fitting years later repeats the decision instead of restarting it.