LED Wire Gauge Selection and Voltage Drop Calculation for 12V and 24V LED Strip Circuits
GL LED
What wire gauge should you use for your LED strip lights? This comprehensive guide explains how to choose the proper AWG (American Wire Gauge) for low-voltage LED strip circuits and accurately calculate voltage drop for 12V and 24V LED lighting systems. Whether you’re installing a small strip or a large run, this article provides the technical details you need to ensure optimal brightness and performance.
Current and Ohm's Law
In low-voltage LED systems, the operating current of LED strips varies with power load. To find out the current (also called amperage, represented by I or A), voltage (represented by V), or resistance (represented by Ω) in a circuit, an equation from Ohm’s Law can be applied. Ohm’s Law has three basic equations, beginning with the statement that voltage is equal to the product of the current and the resistance in a circuit. Using that, we can conclude that the current is also equal to the voltage divided by the resistance, and that the resistance is equal to the voltage divided by the current. In application, the three equations can be used to find a missing value in a circuit and look like this:
V = I×R I = V/R R = V/I
For example, if you have a simple circuit that is known to have a 50V power supply and a point of resistance that is equal to 7Ω, the solving for the current (I) would look like this:
I = V/R
I = 50/7
I = 7.14A
Understanding the basic relationship between voltage, current, and resistance will help when making choices about power supplies and wire gauge.
LED Strip Operating Currents
For LED strips operating on low-voltage circuits, the current differs significantly between 12V and 24V systems. The table below shows the operating current for various power loads:
Load Power |
Operating Current at 12V (A) |
Operating Current at 24V (A) |
|
60 W |
5.00 A |
2.50 A |
|
100 W |
8.33 A |
4.17 A |
|
200 W |
16.67 A |
8.33 A |
|
300 W |
25.00 A |
12.50 A |
AWG Copper Wire Resistance and Voltage Drop Calculation
Understanding AWG and Its Impact on Voltage Drop
AWG is used to denote the thickness of copper wires. Lower AWG numbers indicate thicker wires with lower resistance per unit length. Typical resistance values (at 20°C, per 1000 feet) are as follows:
- AWG18: ~6.385 Ω/1000 ft
- AWG16: ~4.016 Ω/1000 ft
- AWG14: ~2.525 Ω/1000 ft
- AWG12: ~1.588 Ω/1000 ft
- AWG10: ~0.999 Ω/1000 ft
Voltage Drop Calculation Method
In a complete circuit (with both a positive and negative conductor), the effective wire length is twice the one-way distance. If L is the one-way distance (in feet) and R/ft is the resistance per foot of the wire gauge chosen, then:
VD =I×(2L×R/ft)
The actual voltage at the LED strip is the supply voltage minus this voltage drop.
For example, if there is a 24V power supply on a complete circuit with an AWG 18 wire length of 20ft and a resistor of 5Ω in the circuit, the first step would be to solve for I (amperage). Using Ohm’s Law, it would look like this:
I = V/R
I = 24V/5Ω
I = 4.8A
Using the newly found amperage, we can calculate for voltage drop at the LED strip. Since the circuit is complete, the total amount of wire length (20ft) must be doubled for the calculation. To find the resistance per foot of the chosen wire gauge, take the resistance value from the table above and divide the listed resistance by 1,000 to find the resistance per 1 foot. To find the voltage drop amount, it would look like this:
VD = I×(2L×R/ft)
VD = 4.8A×((2×20ft)×(6.385 Ω /1000ft))
VD = 4.8×(40×0.006385)
VD = 4.8(0.2554)
VD = 1.22592
Finally, to find the actual voltage at the LED strip, subtract the calculated voltage drop from the initial voltage from the power supply (24V).
LED Voltage = V – VD
LED Voltage = 24 – 1.22592
LED Voltage = 22.77408V
Make sure that the power supply is large enough to account for voltage drop – for example, if you were using an LED strip that required 24V input, it would not be recommended to use a 24V output power supply because the voltage drop that occurs through the wire would make the voltage slightly less than the required LED strip input, and the strip would not be at its full brightness. For the best results, we recommend making sure that the total wattage of your LED strip circuit is not more than 80% of the total power supply output. This helps the LEDs and the power supply maintain a long lifespan without flickering, noticeable dimming, or burning out.
Detailed Calculations for 12V LED Strip Systems
Why 12V Systems Require Thicker Wire
In 12V LED strip systems, the higher current draw results in a more significant voltage drop. For lower power loads (e.g., 60W and 100W), thinner wires such as AWG18 or AWG16 may work for short distances. However, for loads of 200W or higher, thicker wires (AWG12 or AWG10) are necessary to maintain proper voltage and brightness.
12VDC 60W Load Example (≈5.00A)
The table below shows the voltage drop and the resulting front-end voltage for various AWG wires over different distances:
Length (ft) |
AWG18 Voltage Drop (V) |
AWG18 Front-End Voltage (V) |
AWG16 Voltage Drop (V) |
AWG16 Front-End Voltage (V) |
AWG14 Voltage Drop (V) |
AWG14 Front-End Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-End Voltage (V) |
|
10 |
0.64 |
11.36 |
0.40 |
11.60 |
0.25 |
11.75 |
0.16 |
11.84 |
|
20 |
1.28 |
10.72 |
0.80 |
11.20 |
0.50 |
11.50 |
0.32 |
11.68 |
|
30 |
1.28 |
10.72 |
1.20 |
10.80 |
0.76 |
11.24 |
0.48 |
11.52 |
|
40 |
2.55 |
9.45 |
1.61 |
10.39 |
1.01 |
10.99 |
0.64 |
11.36 |
|
50 |
3.19 |
8.81 |
2.01 |
9.99 |
1.26 |
10.74 |
0.80 |
11.20 |
|
60 |
3.83 |
8.17 |
2.41 |
9.59 |
1.51 |
10.49 |
0.95 |
11.05 |
|
70 |
4.47 |
7.53 |
2.81 |
9.19 |
1.77 |
10.23 |
1.11 |
10.89 |
|
80 |
5.11 |
6.89 |
3.21 |
8.79 |
2.02 |
9.98 |
1.27 |
10.73 |
|
90 |
5.74 |
6.26 |
3.61 |
8.39 |
2.27 |
9.73 |
1.43 |
10.57 |
|
100 |
6.39 |
5.61 |
4.02 |
7.98 |
2.52 |
9.48 |
1.59 |
10.41 |
12VDC 100W Load Example (≈8.33A)
For a 100W load drawing approximately 8.33A, the voltage drop is higher. Thicker wire is needed for longer distances:
Length (ft) |
AWG18 Voltage Drop (V) |
AWG18 Front-End Voltage (V) |
AWG16 Voltage Drop (V) |
AWG16 Front-End Voltage (V) |
AWG14 Voltage Drop (V) |
AWG14 Front-End Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-End Voltage (V) |
|
10 |
1.06 |
10.94 |
0.67 |
11.33 |
0.42 |
11.58 |
0.27 |
11.73 |
|
20 |
2.13 |
9.87 |
1.34 |
10.66 |
0.84 |
11.16 |
0.53 |
11.47 |
|
30 |
3.19 |
8.81 |
2.01 |
9.99 |
1.26 |
10.74 |
0.80 |
11.20 |
|
40 |
4.26 |
7.74 |
2.68 |
9.32 |
1.68 |
10.32 |
1.06 |
10.94 |
|
50 |
5.32 |
6.68 |
3.35 |
8.65 |
2.10 |
9.90 |
1.33 |
10.67 |
|
60 |
6.39 |
5.61 |
4.02 |
7.98 |
2.52 |
9.48 |
1.59 |
10.41 |
|
70 |
7.45 |
4.55 |
4.69 |
7.31 |
2.94 |
9.06 |
1.86 |
10.14 |
|
80 |
8.51 |
3.49 |
5.36 |
6.64 |
3.36 |
8.64 |
2.12 |
9.88 |
|
90 |
9.58 |
2.42 |
6.03 |
5.97 |
3.78 |
8.22 |
2.39 |
9.61 |
|
100 |
10.64 |
1.36 |
6.70 |
5.30 |
4.20 |
7.80 |
2.65 |
9.35 |
12VDC 200W and 300W Load Examples
For higher power LED strips (200W and 300W), the current becomes significantly higher. Detailed tables show that for a 200W load (≈16.67A) and a 300W load (≈25.00A), much thicker wires (AWG12, AWG10, or even AWG8 for very long runs) are required to keep the voltage drop within acceptable limits.
Detailed Calculations for 24V LED Strip Systems
Because 24V systems draw only half the current of their 12V counterparts, the voltage drop is roughly halved. This allows for the use of a slightly thinner wire while still achieving efficient performance.
24V System: 60W and 100W Load Examples
For a 60W load (2.50A) and a 100W load (4.17A) on a 24V system, the following tables demonstrate that even AWG18 or AWG16 wires maintain a higher front-end voltage over various distances compared to 12V systems:
24VDC 60W Load Example (≈2.5A)
Length (ft) |
AWG18 Voltage Drop (V) |
AWG18 Front-End Voltage (V) |
AWG16 Voltage Drop (V) |
AWG16 Front-End Voltage (V) |
AWG14 Voltage Drop (V) |
AWG14 Front-End Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-End Voltage (V) |
|
10 |
0.32 |
23.68 |
0.20 |
23.80 |
0.13 |
23.87 |
0.08 |
23.92 |
|
20 |
0.64 |
23.36 |
0.40 |
23.60 |
0.25 |
23.75 |
0.16 |
23.84 |
|
30 |
0.96 |
23.04 |
0.60 |
23.40 |
0.38 |
23.62 |
0.24 |
23.76 |
|
40 |
1.28 |
22.72 |
0.80 |
23.20 |
0.50 |
23.50 |
0.32 |
23.68 |
|
50 |
1.60 |
22.40 |
1.00 |
23.00 |
0.63 |
23.37 |
0.40 |
23.60 |
|
60 |
1.91 |
22.09 |
1.20 |
22.80 |
0.76 |
23.24 |
0.48 |
23.52 |
|
70 |
2.23 |
21.77 |
1.40 |
22.60 |
0.88 |
23.12 |
0.56 |
23.44 |
|
80 |
2.55 |
21.45 |
1.61 |
22.39 |
1.01 |
22.99 |
0.64 |
23.36 |
|
90 |
2.87 |
21.13 |
1.81 |
22.19 |
1.13 |
22.87 |
0.72 |
23.28 |
|
100 |
3.19 |
20.81 |
2.01 |
21.99 |
1.26 |
22.74 |
0.80 |
23.20 |
24VDC 100W Load Example (≈4.17A)
Length (ft) |
AWG18 Voltage Drop (V) |
AWG18 Front-End Voltage (V) |
AWG16 Voltage Drop (V) |
AWG16 Front-End Voltage (V) |
AWG14 Voltage Drop (V) |
AWG14 Front-End Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-End Voltage (V) |
|
10 |
0.53 |
23.47 |
0.34 |
23.66 |
0.21 |
23.79 |
0.13 |
23.87 |
|
20 |
1.06 |
22.94 |
0.67 |
23.33 |
0.42 |
23.58 |
0.27 |
23.73 |
|
30 |
1.59 |
22.41 |
1.01 |
22.99 |
0.63 |
23.37 |
0.40 |
23.60 |
|
40 |
2.13 |
21.87 |
1.34 |
22.66 |
0.84 |
23.16 |
0.53 |
23.47 |
|
50 |
2.66 |
21.34 |
1.68 |
22.32 |
1.05 |
22.95 |
0.67 |
23.33 |
|
60 |
3.19 |
20.81 |
2.01 |
21.99 |
1.26 |
22.74 |
0.80 |
23.20 |
|
70 |
3.72 |
20.28 |
2.34 |
21.66 |
1.47 |
22.53 |
0.93 |
23.07 |
|
80 |
4.25 |
19.75 |
2.68 |
21.32 |
1.68 |
22.32 |
1.06 |
22.94 |
|
90 |
4.78 |
19.22 |
3.01 |
20.99 |
1.89 |
22.11 |
1.20 |
22.80 |
|
100 |
5.31 |
18.69 |
3.35 |
20.65 |
2.10 |
21.90 |
1.33 |
22.67 |
Additional tables for 200W and 300W loads on a 24V system are provided at the end of the article.
Practical Recommendations for LED Strip Installations
-
For 12V LED Strip Systems:
- Use AWG18 or AWG16 for smaller loads (60W, 100W) and shorter wiring distances.
- For 200W loads, select AWG14 to AWG12.
- For very long runs, AWG10 is recommended.
- For high-power 300W LED strips, use AWG12 or thicker (AWG10 or AWG8) to ensure sufficient voltage reaches the LED strip, minimizing brightness loss.
-
For 24V LED Strip Systems:
- Thanks to lower current draw, a 24V system can use a thinner gauge than a 12V system while maintaining a high front-end voltage.
- A 60W load at 24V can efficiently run on AWG18; for 300W loads, AWG14 is acceptable for medium distances while AWG12 or AWG10 is preferred for longer distances.
Conclusion
Optimizing AWG selection and performing accurate voltage drop calculations are critical for designing efficient low-voltage LED lighting systems. This guide provides a step-by-step approach for both 12V and 24V LED strip circuits, ensuring that your LED installations deliver consistent brightness and reliable performance. Follow these guidelines to enhance your LED lighting setup and achieve energy-efficient, high-quality illumination.
When you're ready to consider your wire and power supply options, check out our large selection of power supplies and our convenient wires and accessories for all of your LED lighting needs!
Additional Detailed Calculations for 12V and 24V LED Strip Systems
The following tables are for 200W and 300W loads on a 12V and 24V system.
12VDC 200W Load (≈16.67A)
Length (ft) |
AWG14 Voltage Drop (V) |
AWG14 Front-end Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-end Voltage (V) |
AWG10 Voltage Drop (V) |
AWG10 Front-end Voltage (V) |
| 10 | 2.1 | 9.9 | 1.33 | 10.67 | 0.84 | 11.16 |
| 20 | 4.2 | 7.8 | 2.65 | 9.35 | 1.67 | 10.33 |
| 30 | 6.3 | 5.7 | 3.98 | 8.02 | 2.51 | 9.49 |
| 40 | 8.4 | 3.6 | 5.3 | 6.7 | 3.34 | 8.66 |
| 50 | 10.5 | 1.5 | 6.63 | 5.37 | 4.18 | 7.82 |
| 60 | 12.6 | 0 | 7.95 | 4.05 | 5.01 | 6.99 |
| 70 | 14.7 | 0 | 9.28 | 2.72 | 5.85 | 6.15 |
| 80 | 16.8 | 0 | 10.6 | 1.4 | 6.68 | 5.32 |
| 90 | 18.9 | 0 | 11.93 | 0.07 | 7.52 | 4.48 |
| 100 | 21 | 0 | 13.25 | -1.25 | 8.35 | 3.65 |
12VDC 300W Load (≈25.00A)
Length (ft) |
AWG12 Voltage Drop (V) |
AWG12 Front-end Voltage (V) |
AWG10 Voltage Drop (V) |
AWG10 Front-end Voltage (V) |
| 10 | 3.17 | 8.83 | 1.99 | 10.01 |
| 20 | 6.35 | 5.65 | 3.99 | 8.01 |
| 30 | 9.52 | 2.48 | 5.98 | 6.02 |
| 40 | 12.7 | 0 | 7.98 | 4.02 |
| 50 | 15.87 | 0 | 9.98 | 2.02 |
| 60 | 19.05 | 0 | 11.97 | 0.03 |
| 70 | 22.22 | 0 | 13.97 | -1.97 |
| 80 | 25.4 | 0 | 15.96 | -3.96 |
| 90 | 28.57 | 0 | 17.96 | -5.96 |
| 100 | 31.75 | 0 | 19.95 | -7.95 |
24VDC 200W Load (≈8.33A)
Length (ft) |
AWG16 Voltage Drop (V) |
AWG16 Front-end Voltage (V) |
AWG14 Voltage Drop (V) |
AWG14 Front-end Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-end Voltage (V) |
AWG10 Voltage Drop (V) |
AWG10 Front-end Voltage (V) |
| 10 | 1.34 | 22.66 | 0.84 | 23.16 | 0.53 | 23.47 | 0.33 | 23.67 |
| 20 | 2.68 | 21.32 | 1.68 | 22.32 | 1.06 | 22.94 | 0.67 | 23.33 |
| 30 | 4.02 | 19.98 | 2.52 | 21.48 | 1.59 | 22.41 | 1 | 23 |
| 40 | 5.36 | 18.64 | 3.36 | 20.64 | 2.12 | 21.88 | 1.34 | 22.66 |
| 50 | 6.7 | 17.3 | 4.2 | 19.8 | 2.65 | 21.35 | 1.67 | 22.33 |
| 60 | 8.04 | 15.96 | 5.04 | 18.96 | 3.18 | 20.82 | 2.01 | 21.99 |
| 70 | 9.38 | 14.62 | 5.88 | 18.12 | 3.72 | 20.28 | 2.34 | 21.66 |
| 80 | 10.72 | 13.28 | 6.72 | 17.28 | 4.25 | 19.75 | 2.68 | 21.32 |
| 90 | 12.06 | 11.94 | 7.56 | 16.44 | 4.78 | 19.22 | 3.01 | 20.99 |
| 100 | 13.4 | 10.6 | 8.4 | 15.6 | 5.31 | 18.69 | 3.35 | 20.65 |
24VDC 300W Load (≈12.50A)
Length (ft) |
AWG14 Voltage Drop (V) |
AWG14 Front-end Voltage (V) |
AWG12 Voltage Drop (V) |
AWG12 Front-end Voltage (V) |
AWG10 Voltage Drop (V) |
AWG10 Front-end Voltage (V) |
| 10 | 1.26 | 22.74 | 0.8 | 23.2 | 0.5 | 23.5 |
| 20 | 2.52 | 21.48 | 1.59 | 22.41 | 1 | 23 |
| 30 | 3.78 | 20.22 | 2.39 | 21.61 | 1.5 | 22.5 |
| 40 | 5.04 | 18.96 | 3.18 | 20.82 | 2 | 22 |
| 50 | 6.3 | 17.7 | 3.98 | 20.02 | 2.5 | 21.5 |
| 60 | 7.56 | 16.44 | 4.78 | 19.22 | 3 | 21 |
| 70 | 8.82 | 15.18 | 5.57 | 18.43 | 3.5 | 20.5 |
| 80 | 10.08 | 13.92 | 6.37 | 17.63 | 4 | 20 |
| 90 | 11.34 | 12.66 | 7.17 | 16.83 | 4.5 | 19.5 |
| 100 | 12.6 | 11.4 | 7.96 | 16.04 | 5 | 19 |
