Voltage Drop Calculator
Prevent color-shift and dimming in architectural linear lighting. Calculate exact DC wire decay incorporating ambient thermal resistance, and verify AWG wire gauge suitability.
LED Strip Voltage Drop
Calculate DC wire decay & thermal resistance
Voltage Drop
Optimal. Voltage drop complies with SS 638:2018 limits (< 4%).
Understanding Voltage Drop & Thermal Derating
Voltage drop is the leading cause of failure and color-shift in high-end architectural linear lighting installations. Electrical contractors must ensure that the voltage reaching the LEDs complies with the SS 638:2018 standard (formerly Singapore Standard CP5).
- I (Current in Amps): Total load (Watts) divided by System Voltage (V).
- ρ_T (Thermal Resistivity): Copper resistivity adjusts dynamically with temperature: ρ_T = ρ_20 × [1 + 0.00393(T - 20)].
- L (Length): Cable length from the driver to the strip, multiplied by 2 for the return DC loop.
- A (Area): Cross-sectional area of the wire in mm² (derived from AWG rating).
How to Prevent Linear LED Voltage Drop
- Upgrade bus distribution from 12V/24V to 48V DC.
- Increase conductor cross-section (AWG to mm²).
- Implement dual-ended or center-feed topologies.
- Position remote drivers closer to the load.
The 48V Advantage
As seen in the calculator, running a high-wattage load over a long distance on a 12V or 24V system requires massive copper cables to avoid failure. By upgrading to a 48V system, the current (I) is halved (or quartered compared to 12V). This drastically reduces resistive power dissipation (I²R), allowing you to use thinner wires and mount power supplies further away.
Professional Disclaimer
This tool estimates voltage drop based on standard electrolytic copper physics. Actual results may vary due to poor terminal connections, continuous FPC track resistance decay, or wire impurities. For formal engineering submittals, always adhere to local electrical codes (SS 638:2018, formerly CP5) and consult a licensed Professional Engineer (PE).
Require 48V Linear Systems?
We supply European linear profiles designed to overcome long-run voltage drops.
- DGA Cometa & Armonia 48V
- Casambi PWM4 Controllers
Frequently Asked Questions
Why does my LED strip dim at the end?
This is caused by voltage drop. As direct current (DC) travels through the copper wire, the inherent resistance of the copper causes the voltage to decay. If the voltage drops beyond acceptable limits, the LEDs at the end of the strip will appear visibly dimmer and exhibit a chromaticity shift.
How does ambient temperature affect voltage drop?
The electrical resistance of copper increases with temperature. In unconditioned tropical environments (like a 45°C ceiling plenum in Singapore), copper resistivity increases significantly compared to the standard 20°C baseline, compounding voltage drop over long linear runs.
How do I prevent linear LED voltage drop?
To prevent linear LED voltage drop, follow these sequential engineering steps: 1) Upgrade bus distribution from 12V/24V to 48V DC. 2) Increase conductor cross-section (AWG to mm²). 3) Implement dual-ended or center-feed topologies. 4) Position remote drivers closer to the load.