OSCAR - Misc011 - Wire Sizing

Owatonna Steele County Amateur Radio

06-Aug-2015

2% Wire Loss Chart

In a low voltage system, the maximum voltage drop in the power cables should be less than 2%.
For a nominal 12 volt circuit, a 2% loss represents 0.25 volts.

This chart estimates the maximum distance of a two conductor copper cable from the power source to the load resulting in a 2% voltage drop.
	Wire Size
Amps	#18	#16	#14	#12	#10	#8	#6	#4
1	18	29	47	74	118	187	298	474
2	9	15	23	37	59	94	149	237
3	6	10	16	25	39	62	99	158
4	5	7	12	19	29	47	74	119
5	4	6	9	15	24	37	60	95
6	3	5	8	12	20	31	50	79
7	3	4	7	11	17	27	43	68
8	2	4	6	9	15	23	37	59
9	2	3	5	8	13	21	33	53
10	2	3	5	7	12	19	30	47
15	1	2	3	5	8	13	20	32
20	1	2	2	4	6	9	15	24
25	1	1	2	3	5	8	12	19
30		1	2	3	4	6	10	16
35			1	2	3	5	8	14
40			1	2	3	5	7	12
45			1	2	3	4	7	11
50			1	2	2	4	6	10

This chart estimates the voltage drop of a two conductor copper cable
from the power source to the load.

Wire Size

Amps #18 #16 #14 #12 #10 #8 #6 #4

1 0.128 0.080 0.051 0.032 0.020 0.013 0.008 0.005

2 0.255 0.161 0.101 0.064 0.040 0.025 0.016 0.010

3 0.383 0.241 0.152 0.095 0.060 0.038 0.024 0.015

4 0.511 0.321 0.202 0.127 0.080 0.050 0.032 0.020

5 0.639 0.402 0.253 0.159 0.100 0.063 0.040 0.025

6 0.766 0.482 0.303 0.191 0.120 0.075 0.047 0.030

7 0.894 0.562 0.354 0.222 0.140 0.088 0.055 0.035

8 1.022 0.643 0.404 0.254 0.160 0.101 0.063 0.040

9 1.149 0.723 0.455 0.286 0.180 0.113 0.071 0.045

10 1.277 0.803 0.505 0.318 0.200 0.126 0.079 0.050

15 1.916 1.205 0.758 0.476 0.300 0.188 0.119 0.075

20 2.554 1.606 1.010 0.635 0.400 0.251 0.158 0.099

25 3.193 2.008 1.263 0.794 0.499 0.314 0.198 0.124

30 3.831 2.410 1.515 0.953 0.599 0.377 0.237 0.149

35 4.470 2.811 1.768 1.112 0.699 1.440 0.277 0.174

40 5.108 3.213 2.020 1.270 0.799 0.503 0.316 0.199

45 5.747 3.614 2.273 1.429 0.899 0.565 0.356 0.224

50 6.385 4.016 2.525 1.588 0.999 0.628 0.395 0.249

This chart estimates the power loss (Watts) in a two conductor copper cable
from the power source to the load.

Wire Size

Amps #18 #16 #14 #12 #10 #8 #6 #4

1 0.128 0.080 0.051 0.032 0.020 0.013 0.008 0.005

2 0.511 0.321 0.202 0.127 0.080 0.050 0.032 0.020

3 1.149 0.723 0.455 0.286 0.180 0.113 0.071 0.045

4 2.043 1.285 0.808 0.508 0.320 0.201 0.126 0.080

5 3.193 2.008 1.263 0.794 0.499 0.314 0.198 0.124

6 4.597 2.892 1.818 1.143 0.719 0.452 0.284 0.179

7 6.257 3.936 2.475 1.556 0.979 0.616 0.387 0.244

8 8.173 5.140 3.232 2.033 1.279 0.804 0.506 0.318

9 10.34 6.506 4.091 2.573 1.618 1.018 0.640 0.403

10 12.77 8.032 5.050 3.176 1.998 1.256 0.790 0.497

15 28.73 18.07 11.36 7.146 4.495 2.827 1.778 1.118

20 51.08 32.13 20.20 12.70 7.991 5.026 3.161 1.988

25 79.81 50.20 31.56 19.85 12.49 7.853 4.939 3.106

30 114.9 72.29 45.45 28.58 17.98 11.31 7.112 4.473

35 156.4 98.39 61.86 38.91 24.47 15.39 9.680 6.088

40 204.3 128.5 80.80 50.82 31.97 20.10 12.64 7.952

45 258.6 162.6 102.3 64.31 40.46 25.44 16.00 10.06

50 319.3 200.8 126.3 79.40 49.95 31.41 19.76 12.43

Section Index