How to Plan Power for a 20m COB LED Strip Run
To plan power for a 20m COB LED strip run, confirm the strip’s rated voltage and watts per metre, multiply its power rating by 20m, then select a compatible power supply with a suitable capacity margin. Do not assume a single power connection can deliver even brightness along the full length: voltage drop, cable length, strip design, and connection ratings all matter. For many installations, dividing the run into shorter sections and feeding them in parallel is a more dependable approach than powering the entire length from one end. At ENTA Lighting, we recommend checking the exact strip and installation specifications before finalizing the power and wiring plan.
Start with the Strip’s Electrical Specifications
COB describes the LED packaging style; it does not determine the strip’s voltage, power consumption, or maximum supported run length. Those values depend on the specific product. Before sizing a driver, find the rated input voltage, watts per metre, recommended maximum connection length, and any manufacturer guidance for power injection on the product specification or label.
Use the strip’s stated power consumption rather than estimating from appearance or brightness. If a listing gives only total power for a reel, confirm the reel length and whether that rating applies to the full reel. Also check whether the power figure is specified at full output, since dimming may reduce consumption but should not be used to undersize the supply.
Step-by-Step Power Planning
1. Calculate the strip’s total load
Multiply the strip’s rated power per metre by the installed length. For example, if a particular strip is rated at 10W/m, a 20m run requires 200W at full output: 10W/m × 20m = 200W. This is an illustrative calculation, not a specification for every 20m COB LED strip.
If the product rating is given per reel instead, use that stated total, provided the reel length matches the planned installation. Allow for any extra strip needed around corners or to reach connection points when calculating the installed length. Do not connect additional sections beyond the product’s stated limits without confirming the arrangement with the manufacturer.
2. Choose the correct output voltage and capacity
The power supply output voltage must match the strip’s rated input voltage. A 24V strip requires a compatible 24V supply, for example; using a different voltage can prevent correct operation and may damage the product. Select a supply based on the calculated total load and its specified operating conditions.
As a planning example, a 200W load could be paired with a 240–250W supply to provide approximately 20–25% capacity allowance. This is a practical margin to consider, not a universal rule or a substitute for the power supply manufacturer’s derating guidance. Check ambient temperature, enclosure conditions, dimmer compatibility, and any project requirements before making a final selection.
3. Calculate current for wiring and connections
Estimate current by dividing power by voltage: current (A) = power (W) ÷ voltage (V). For the illustrative 200W load, a 24V system draws about 8.33A, while a 12V system draws about 16.7A. These figures represent the total load at the stated power and voltage; they do not specify the current in each branch of a split-feed installation.
Use the calculated current to check cable, terminals, connectors, dimmers, and distribution components. Their current ratings must suit the load they actually carry. Cable size should also account for cable length and acceptable voltage drop, so have the installation designer or a qualified electrician verify it against the applicable electrical requirements.
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4. Plan the power-feed layout
A long strip can experience a voltage difference between its feed point and more distant sections. Depending on the product and installation, this may appear as reduced brightness or uneven light output toward the far end. The degree of change depends on factors such as strip design, input voltage, load, conductor resistance, and feed arrangement, so a universal maximum length cannot be assumed.
Consider splitting the 20m installation into multiple sections and feeding those sections from a suitable distribution point. Parallel feeds can help avoid making one strip section carry the entire run’s current, but each branch must still be designed for its own load and protected appropriately. Follow the strip manufacturer’s instructions: some products specify particular feed positions, section lengths, or connection methods.
Key Decisions Before Installation
- Single-end feed or multiple feeds: Use the manufacturer’s maximum run and feed guidance as the starting point. If the proposed 20m arrangement exceeds the stated limit, plan additional feeds or divide the installation as recommended.
- One supply or separate supplies: Base the decision on total load, product instructions, wiring distances, and the project’s control system. Multiple supplies must be coordinated with the strip and dimmer arrangement rather than connected together arbitrarily.
- Dimmer and control compatibility: Confirm that the dimmer supports the strip’s voltage, load type, and current. Check the controller’s output rating and whether the project needs a suitable amplifier or separate controlled zones.
- Installation environment: Confirm whether the strip and power supply are suitable for the location. Allow for the power supply’s ventilation and mounting requirements, and install the strip on an appropriate surface according to its product instructions.
- Service access: Position supplies and connections where they can be inspected and replaced. Avoid concealing components in inaccessible spaces unless the project design and local requirements permit it.
Common Power-Planning Mistakes
Assuming 20m is safe from one connection
A reel length is not necessarily the maximum length that can be powered from one end. The permissible run depends on the exact product and connection arrangement. Confirm the manufacturer’s limit rather than treating a continuous 20m physical run as proof that a single feed will provide suitable performance.
Choosing a supply by voltage alone
Matching voltage is essential, but it does not confirm that a supply can provide enough power or current. Compare its output capacity with the calculated load, then account for manufacturer operating limits and the installation environment. Also verify that the power supply and controls are compatible with one another.
Ignoring cable and connector ratings
A correctly sized power supply cannot compensate for an underspecified cable, connector, or terminal. Check component ratings against the current each part will carry, and include the full cable route in the voltage-drop assessment. Use qualified electrical support where the installation requires it.
How ENTA Lighting Can Support Project Planning
For B2B projects, we can help review the information needed to plan a 20m COB LED strip installation, including the selected strip’s voltage, power per metre, proposed run layout, control method, and installation conditions. Buyers should share a drawing or a clear description of feed locations and cable distances when requesting a recommendation. This helps our team assess product fit and identify which specifications or wiring details need confirmation.
Before placing an order, request the relevant product data for the exact strip configuration under consideration. Confirm the allowable run length, power-feed guidance, and any compatibility requirements for the chosen driver or controller. Final wiring and installation should be checked by a qualified professional against project requirements and applicable local electrical rules.
Summary and Next Steps
Plan power for a 20m COB LED strip by verifying the exact product specifications, calculating total watts, matching the supply voltage, and checking current and component ratings. Then decide whether the layout needs multiple feed points or separate sections, using the manufacturer’s run-length guidance rather than assuming one-end power will be adequate. In the illustrative example of a 10W/m strip, the 20m load is 200W; actual requirements will vary with the selected product.
For your next step, prepare the strip voltage, watts per metre, total length, intended feed positions, cable distances, and dimming requirements. Share these details with ENTA Lighting when requesting product and project support. We can help you review the relevant product specifications so your team can finalize a suitable power and installation plan.