Types of LED strip lights: 12 V or 24 V, SMD or COB, and which IP rating?

Written by Engin Demirel · Electrical technician, master instructor · 12 years of experience

Short answer: LED strips differ by voltage (12 V or 24 V), chip type (SMD 2835, 5050 or dotless COB), LEDs and watts per metre, protection rating (IP20 indoors, IP65 and IP67 for damp or outdoor areas) and colour (single white, tunable white, RGB, RGBW). For cove lighting, under-cabinet and shelf lighting at home, the usual choice is a 24 V, high-density or COB, IP20 strip in 2700–4000 K. Mounted in an aluminium profile with a diffuser, the strip lasts longer and shows no visible dots.

12 V or 24 V?

12 V: common for short runs of a few metres, furniture, vehicles and hobby projects. Cut intervals are usually shorter.
24 V: draws half the current for the same power, so voltage drop is lower and long runs show less difference in brightness and colour from start to end. Preferred for coves, shelves and kitchen cabinets.

The strip and the driver must have the same voltage. A 24 V strip will not light on a 12 V driver, and a 12 V strip is destroyed on a 24 V driver. Work out the driver size with the formula in our LED strip power supply sizing guide.

SMD or COB?

SMD 2835: today's most common chip for white strips (2.8 × 3.5 mm), efficient and economical.
SMD 5050: a larger 5 × 5 mm chip that can hold three light points, so it is common in RGB strips.
COB (chip on board): the chips sit very close together under a continuous phosphor layer. It gives a smooth line of light without dots even without a profile, ideal on glossy surfaces where reflections show.

More LEDs per metre (60, 120, 168 LED/m and higher) means the dots sit closer and look smoother behind a diffuser. Light output, however, depends on watts and lumens per metre, not on the LED count, so check the W/m and lm/m values.

IP rating: IP20, IP65, IP67

IP20: no protection, for dry indoor spaces such as coves, cabinets and shelves.
IP65: silicone coated, resists splashing water. Kitchen worktops, bathrooms (in the right zone), eaves.
IP67 and IP68: silicone sleeve or fully potted, for temporary or permanent exposure to water. Outdoors and harsh conditions.

The driver and connections of a waterproof strip must also suit the environment; the strip alone does not protect the system. Our guide to bathroom lighting zones explains what goes where.

Colour options

Single colour white: a fixed tone such as 2700 K, 3000 K or 4000 K; the most popular choice at home.
Tunable white (CCT): warm and cool white LEDs combined; with a suitable controller the tone changes during the day.
RGB: coloured light by mixing red, green and blue. It makes white by mixing and does not give a clean, natural white.
RGBW / RGBWW: RGB plus a separate white LED, for both colour and good-quality white light.

Coloured and tunable strips need a matching controller (remote, DALI or smart home). For dimming a single-colour strip use a dimmable driver; see dimmable LEDs and dimmers.

Length, voltage drop and feed points

The longer the strip, the more voltage is lost along the copper tracks and the dimmer the far end becomes. As a rule:

Feed a 12 V strip from one end for up to about 5 m, a 24 V strip for 5–10 m (check the manufacturer's data).
Feed longer runs from both ends or from the middle; do not chain strips and feed them from one end.
Keep the cable from driver to strip short or increase its cross-section.
Cut the strip only at the marked cut points.

Profiles and diffusers

An aluminium profile spreads the heat, extends the strip's life and gives a straight mounting surface. Profile types:

Surface mounted: screwed or glued to the surface.
Recessed: set into plasterboard or furniture, flush with the surface.
Corner profile: for cabinet corners and 45° light.

An opal diffuser hides the dots; a clear one lets more light through but the dots stay visible. In a cove the strip faces up and towards the wall; see how to make cove lighting.

LED strips in our shop

Our LED strips category includes Lamptime LED strips and LED bar profiles. Lamptime BS24 runs on 24 V with 60, 120 and 168 LED/m versions and, depending on the version, 14 W or 5 W per metre. Lamptime BS12 runs on 12 V with 60 LED/m. Both are IP20, CRI 80 and Class III, available from 2700 K to 6500 K and sold as 5 m reels. They are meant for dry indoor use.

Frequently asked questions

Is a 12 V or 24 V LED strip better?

For long runs 24 V is better: it draws half the current for the same power, so the far end dims less. For short, small projects 12 V is enough. Strip and driver must have the same voltage.

What is the difference between SMD and COB LED strips?

On an SMD strip the LEDs are spaced and the dots can show. On a COB strip the chips are packed tightly under a continuous layer, giving a dotless line of light even without a profile.

Which IP rating do I need for a kitchen or bathroom?

Where water splashes, use at least an IP65 strip and a suitable driver. IP20 is fine for dry indoor areas; IP67 is preferred outdoors.

What is the difference between RGB and RGBW?

RGB makes white by mixing three colours and does not give a natural white. RGBW adds a separate white LED, giving both colour and good white light.

How long can an LED strip be fed from one end?

Usually up to about 5 m for 12 V and 5–10 m for 24 V. Longer runs should be fed from both ends or the middle; check the manufacturer's data.

Can I use an LED strip without a profile?

Low-power strips can be used without one, but an aluminium profile spreads heat, extends life and, with an opal diffuser, hides the dots. High-power strips need a profile.