Voltage Drop Calculator

Understanding Voltage Drop

Voltage drop is the reduction in voltage in an electrical circuit between the source and load. It is important to calculate voltage drop to ensure the efficiency and safety of the electrical system.

Factors Affecting Voltage Drop

Several factors affect voltage drop, including the length of the conductor, the material of the conductor, the cross-sectional area of the conductor, and the current flowing through the conductor.

How to Minimize Voltage Drop

To minimize voltage drop, use conductors with larger cross-sectional areas, reduce the length of the conductors, and use materials with lower resistivity such as copper or aluminum.

Voltage Drop Calculation Formula

To calculate the voltage drop, input the current, length, material, AWG, and type of circuit. The calculator will use the appropriate formula to determine the voltage drop.

For AC Single-phase and DC circuits:

$$ V_{drop} = \frac{2 \times I \times \rho \times L}{A} $$

For Three-phase circuits:

$$ V_{drop} = \frac{\sqrt{3} \times I \times \rho \times L}{A} $$

AWG to mm² and Resistance

Use the table below to find the cross-sectional area and resistance for different AWG sizes:

AWG	Cross-Sectional Area (mm²)	Resistance (Ohms per 1000m)
0000 (4/0)	107.22	0.1608
000 (3/0)	85.029	0.2028
00 (2/0)	67.431	0.2557
0 (1/0)	53.475	0.3224
1	42.408	0.4066
2	33.631	0.5127
3	26.67	0.6464
4	21.151	0.8152
5	16.773	1.028
6	13.302	1.296
7	10.549	1.634
8	8.366	2.061
9	6.634	2.599
10	5.261	3.277
11	4.172	4.132
12	3.309	5.211
13	2.624	6.571
14	2.081	8.285
15	1.65	10.448
16	1.309	13.174
17	1.038	16.612
18	0.823	20.948
19	0.6527	26.415
20	0.5176	33.308
21	0.4105	42.001
22	0.3255	52.962
23	0.2582	66.784
24	0.2047	84.213
25	0.1624	106.19
26	0.1288	133.9
27	0.1021	168.85
28	0.081	212.92
29	0.0642	268.48
30	0.0509	338.55
31	0.0404	426.9
32	0.032	538.32
33	0.0254	678.8
34	0.0201	855.96
35	0.016	1,079.3
36	0.0127	1,361
37	0.01	1,716.2
38	0.007967	2,164.1
39	0.006318	2,728.9
40	0.00501	3,441.1

How much voltage drop is acceptable

The acceptable voltage drop is typically within 5%, but it can vary based on electrical system requirements, load conditions, cable types, length, and national/regional electrical standards.

What is 3% voltage drop rule