Blog
Choosing the input voltage of an LED strip run
This catalogue publishes two models that frame the voltage question perfectly. The addressable strip's page prints a low, single-figure input voltage of the class used by individually driven pixel product. The programmable string light's page prints an input several times higher, of the class used by ride and signage strings. Neither is a spec-sheet accident: each voltage belongs to the kind of work the product does, and the choice between the classes — when a project genuinely has one — is worth understanding rather than inheriting.
BLOG — VOLTAGE IS A WIRING DECISION BEFORE IT IS A PRODUCT ONE
Two published models, two voltage classes
Voltage itself lights nothing. What it governs is current, and current governs almost everything physical about an installation: how much power a cable of a given thickness can carry, how quickly brightness falls along a run, and how often a long line must be fed. Choosing a voltage class is therefore a wiring decision taken before it is a product decision.
Current is the real subject
For the same delivered power, the higher-voltage class draws proportionally less current, and current is what heats cables and drops along them. A long run in the low-voltage class can arrive at its far end visibly dimmer than its near end unless power is injected at intervals — a well-known behaviour of addressable strip, and the reason experienced installers plan feed points the way they plan the run itself. The higher-voltage class pushes the same power through thinner, longer cable with less drama, which is one reason strings for rides and boards live there.
The low-voltage class answers with its own virtues. It is the native territory of addressable pixels: the chips that give each LED its own instruction are low-voltage devices, and the density and data behaviour that stage and display work wants exists there. Safety and power-supply practice also differ between the classes, in ways an installer prices into the job. Neither class is the professional one; each is professional for its work.
The arithmetic behind the feed-point habit is worth stating plainly. Voltage drop along a cable grows with the current it carries and the distance it travels. Halve the voltage and the same power demands twice the current, so the same cable drops twice the voltage over the same length — and the run's far end, already the lowest point, falls further. That is the whole mechanism behind the dim tail on an under-fed low-voltage run, and it has only three remedies: shorten the legs, thicken the cable, or feed from more points. The higher-voltage class buys its longer legs with exactly this arithmetic, at the price of the safety and handling discipline its voltage deserves.
What the choice changes on site
Feed points multiply as voltage falls and runs lengthen — budget them as components, with cable and labour attached, not as surprises. Power supplies are class-specific: a supply bought for one class is inventory, not a spare, for the other. Control placement follows the same logic, because the controller, the first feed and the start of the data path like to live together, and on a higher-voltage string that point may be a cabinet at the structure's base rather than a box at the run's start.
Mixed sites are normal and should be planned as mixed: addressable strip where the effect demands it, higher-voltage strings where the structure does, each with its own supply and its own spares. The failures come from pretending the site is one class when it is two — shared supplies, borrowed cable, a single spare expected to cover both.
Label the classes where they meet. The junction between a low-voltage feature and a higher-voltage run is the one place a tired installer can mate the wrong supply to the wrong strip, so the drawing marks it, the cabinet labels it, and the two classes' connectors are never left interchangeable by accident. Separation is not bureaucracy; it is the cheap half of safety.
Two classes in one building
| Low-voltage class (the published strip) | Higher-voltage class (the published string) | |
|---|---|---|
| Native work | Dense addressable effects, per-LED control | Long structural strings on rides and boards |
| Current for the same power | High — thick cable, short legs between feeds | Low — longer cable runs stay practical |
| Feed points | Several along a long run, planned on the drawing | Fewer; placement follows the structure |
| Spares discipline | Supplies and reels held per class | Not interchangeable with the other class |
Most real venues run both classes at once: strip where the audience is close and the effect must move, strings where the structure is large and the season is long. The building does not care that they differ; the electrical plan must. Separate supplies, labelled cabinets and spares held per class are the unglamorous price of using each class where it is strong, and they are cheaper than the alternative — forcing one class to do the other's work and engineering around its weaknesses for a decade.
Feeding the far end
The single most useful habit in the low-voltage class is feeding a run from both ends, or from the middle, wherever the drawing allows it. Brightness along an addressable run is a map of its voltage, and a run fed at one end draws that map as a gradient nobody designed. Feed points are cheap at drawing stage and embarrassing at commissioning stage, when the far end of a feature glows at a visibly different strength from its start and the only remaining fixes involve opening finished work.
The higher-voltage class forgives more, which is precisely its danger: runs grow by accretion, a section is added each season, and the day arrives when the accumulated length asks questions of the original feed. Draw the grown version of the installation — the one the venue will actually have in five years — and feed for that, in whichever class the run belongs to.
Bring that measurement habit to the inquiry and the quotation improves on contact: a supplier told the run's length, class and feed plan can price the whole system, cables and supplies included, instead of pricing a reel and leaving the engineering as a surprise. The drawing is the cheapest engineer a lighting buyer will ever hire.
Deciding for your run
Start from the effect and the distance, in that order. If the run must be addressable and dense, the class is chosen for you and the engineering is feed points. If the run is long, structural and outdoors, the higher class earns its place and the engineering is placement and sealing. Read the two model pages side by side — the strip's table and the string's table are the fixed points — and let the run's length, from the drawing, cast the deciding vote.
Before you order
Sourcing light lines like these? Talk to the sales team — one form covers every line, and the reply quotes against your model, quantity and destination.