The Musan RD.24 is a 26mm round low-voltage step marker in black sand 24V, 3W giving 18lm at 3000K,IP54.

It is 26mm across, not 840. Our specification tablegave it as 840mm wide by 840mm high with a 260mm projection nearly a metre square, standing a quarter of a metre off the wall. It weighs200grams. The datasheet records2.6cm 26mm, which is the only figure the weight supports, and the260mm projection is that same 2.6cm multiplied by a hundred instead of ten.Corrected here.

A marker, and only a marker

18 lumens. That is not a typo and it is not much: it isenough to see where the step is and not enough to light the stepsurface. That is the correct behaviour for a stair marker a bright light at ankleheight on a staircase is worse than a dim one, because it dazzles the person descending butbuy it knowing what it does.

3W giving 18lm is 6lm per watt, which islow even for a deeply shielded marker. Either most of the light is absorbed inside the body, or oneof the two figures is understated. Published as Telbix records them, andwe have asked. Either way, plan it as a marker.

24 volts and you need a transformer

This is ClassIII low-voltage: it runs on 24V, andno transformer is supplied with it. That is a real cost and a real planning item,because the transformer has to live somewhere dry and be sized for every fitting on the run.

We stock the transformers. A24V 60W and a 24V 200W outdoor unit. At3W each, the 60W will drive a substantial run of Musans leave headroom rather thanloading it to the limit. Ask us and we will size it against your layout.

IP54 covered steps, not exposed ones

IP54 is rated against splashing water, not against water running down a stair andpooling against the riser. So the Musan belongs in acovered stairwell, a sheltered entry, an internal stair or a verandah step.

For uncovered outdoor steps, choose the Halon ST1 instead IP67, dust-tight and rated for temporary immersion. On a stair that is agenuine difference: water runs downward and collects exactly where a step light sits.

Aluminium in black sand

Sand-textured rather than gloss, which at ankle height matters: a gloss face at26mm catches every passing light and reads as a bright dot. The Musan also comes in asquare version if you prefer the geometry.

It is fixed at 3000K and not dimmable. On an18lm marker that is entirely reasonable. A licensed electrician handles the 240V side andthe transformer.

Where it works

• Covered stairs and stairwells internal or sheltered.
• Sheltered entries and verandah steps.
• Runs of several on one transformer.
• Uncovered outdoor steps use the Halon ST1 at IP67.
• A 24V transformer is required and is not supplied.

Specifying it

26mm across not the 840mm our old table stated at0.2kg, in aluminium, black sand. Integrated3W LED giving 18lm at 3000K, included,CRI>80, not dimmable.24V a transformer is REQUIRED and is not supplied; we stock 60W and200W. ClassIII low voltage,IP54 splash-rated; covered steps only. Warranty is three years, as areplacement warranty.

Supplied and supported by Lights For You.

Questions

How big is it really?

26mm across. Our specification table said 840mm square with a 260mm projection nearly a metre wide, on a fitting that weighs 200 grams. The datasheet records 2.6cm, which is the only figure the weight supports.

Is 18 lumens enough?

Enough to see where the step is; not enough to light the step surface. That is the correct behaviour for a stair marker a bright light at ankle height dazzles the person descending but buy it knowing what it does.

Do I need a transformer?

Yes. It runs on 24V and none is supplied. We stock a 24V 60W and a 200W outdoor unit; at 3W each the 60W will drive a substantial run. Ask us and we will size it against your layout.

Can it go on open outdoor steps?

Not ideally. IP54 is rated against splashing, not against water running down a stair and pooling against the riser. For uncovered steps choose the Halon ST1 at IP67 dust-tight and rated for temporary immersion.

Why does 3W only give 18 lumens?

That is 6 lumens per watt, which is low even for a deeply shielded marker either most of the light is absorbed inside the body or one of the figures is understated. We have published Telbixs numbers as recorded and asked them. Plan it as a marker either way.

Round or square?

Both exist the same fitting in two geometries. Choose by what the rest of the stair looks like.

Can I dim it?

No, and it is fixed at 3000K. On an 18lm marker that is entirely reasonable.