50 Amp Wire Knowledge Brochure

50 Amp current is most commonly used in homes, RVs, boats, and automobiles on wires.While the voltage of the circuit primarily determines the power transmitted, the energy efficiency and cable temperature depend on the thickness and resistance of the wire. In this article we will explore what we know about 50 amp wire sizes.

Catalog

AWG Wire Gauge Size Chart

The table below outlines the essential attributes of different AWG wire gauges, such as ampacity, which is the capacity of the wire to carry current.

AWG #	Diameter (mm/inches)	Area (mm2/in2)	Resistance (Copper) (mΩ/m;mΩ/ft)	Ampacity (A)
				@60°C/140°F	@75°C/167°F	@90°C/194°F
4/0 (0000)	11.6840 0.4600	107.2193 0.1662	0.1608 0.04901	195	230	260
3/0 (000)	10.4049 0.4096	85.0288 0.1318	0.2028 0.06180	165	200	225
2/0 (00)	9.2658 0.3648	67.4309 0.1045	0.2557 0.07793	145	175	195
AWG 0 (1/0)	8.2515 0.3249	53.4751 0.0829	0.3224 0.09827	125	150	170
1	7.3481 0.2893	42.4077 0.0657	0.4066 0.1239	110	130	145
2	6.5437 0.2576	33.6308 0.0521	0.5127 0.1563	95	115	130
3	5.8273 0.2294	26.6705 0.0413	0.6465 0.1970	85	100	115
AWG 4	5.1894 0.2043	21.1506 0.0328	0.8152 0.2485	70	85	95
5	4.6213 0.1819	16.7732 0.0260	1.028 0.3133	-	-	-
AWG 6	4.1154 0.1620	13.3018 0.0206	1.296 0.3951	55	65	75
7	3.6649 0.1443	10.5488 0.0164	1.634 0.4982	-	-	-
AWG 8	3.2636 0.1285	8.3656 0.0130	2.061 0.6282	40	50	55
9	2.9064 0.1144	6.6342 0.0103	2.599 0.7921	-	-	-
AWG 10	2.5882 0.1019	5.2612 0.0082	3.277 0.9989	30	35	40
11	2.3048 0.0907	4.1723 0.0065	4.132 1.260	-	-	-
AWG 12	2.0525 0.0808	3.3088 0.0051	5.211 1.588	20	25	30
13	1.8278 0.0720	2.6240 0.0041	6.571 2.003	-	-	-
AWG 14	1.6277 0.0641	2.0809 0.0032	8.286 2.525	15	20	25
15	1.4495 0.0571	1.6502 0.0026	10.45 3.184	-	-	-
16	1.2908 0.0508	1.3087 0.0020	13.17 4.016	-	-	18
17	1.1495 0.0453	1.0378 0.0016	16.61 5.064	-	-	-
AWG 18	1.0237 0.0403	0.8230 0.0013	20.95 6.385	10	14	16
19	0.9116 0.0359	0.6527 0.0010	26.42 8.051	-	-	-
20	0.8118 0.0320	0.5176 0.0008	33.31 10.15	5	11	-
21	0.7229 0.0285	0.4105 0.0006	42.00 12.80	-	-	-
22	0.6438 0.0253	0.3255 0.0005	52.96 16.14	3	7	-
23	0.5733 0.0226	0.2582 0.0004	66.79 20.36	-	-	-
24	0.5106 0.0201	0.2047 0.0003	84.22 25.67	2.1	3.5	-
25	0.4547 0.0179	0.1624 0.0003	106.2 32.37	-	-	-
26	0.4049 0.0159	0.1288 0.0002	133.9 40.81	1.3	2.2	-
27	0.3606 0.0142	0.1021 0.0002	168.9 51.47	-	-	-
28	0.3211 0.0126	0.0810 0.0001	212.9 64.90	0.83	1.4	-
29	0.2859 0.0113	0.0642 0.0001	268.5 81.84	-	-	-
30	0.2546 0.0100	0.0509 0.0001	338.6 103.2	0.52	0.86	-
31	0.2268 0.0089	0.0404 0.0001	426.9 130.1	-	-	-
32	0.2019 0.0080	0.0320 0.0000	538.3 164.1	0.32	0.53	-
33	0.1798 0.0071	0.0254 0.0000	678.8 206.9	-	-	-
34	0.1601 0.0063	0.0201 0.0000	856.0 260.9	0.18	0.3	-
35	0.1426 0.0056	0.0160 0.0000	1079 329.0	-	-	-
36	0.1270 0.0050	0.0127 0.0000	1361 414.8	-	-	-
37	0.1131 0.0045	0.0100 0.0000	1716 523.1	-	-	-
38	0.1007 0.0040	0.0080 0.0000	2164 659.6	-	-	-
39	0.0897 0.0035	0.0063 0.0000	2729 831.8	-	-	-
40	0.0799 0.0031	0.0050 0.0000	3441 1049	-	-	-

Note: The given ampacity values are valid for wires enclosed in an environment with an ambient temperature of 86°F (30°C).

Calculating the Correct Wire Gauge

When selecting the wire gauge suitable for a 50-ampere current, it's crucial to evaluate the wire’s thickness at the desired operating temperature. While 167°F (75°C) is commonly used for calculations, it’s worth pondering: could a lower operational temperature enhance safety? For instance, even 140°F (60°C) is sufficiently high to prevent prolonged contact without protection. Thus, opting for a lower temperature threshold can significantly improve safety margins.

Following the "80% Rule" for Current Capacity

The "80% Rule" in wire size calculations underscores the necessity to choose a wire whose current-carrying capacity exceeds 62.5 amperes. This could lead us to ask, what are the benefits of such a rule in electrical installations?

Here's the calculation:

Current-carrying capacity = 50 amps / 0.80 = 62.5 amps

Referring to Wire Tables for Optimal Choices

According to wire tables, the optimal wire choices for a 50-amp circuit are:

T = @60°C/140°F) → Ampacity = 70 Amps → AWG 4

T = @75°C/167°F → Ampacity = 65 Amps → AWG 6

T = @90°C/194°F → Ampacity = 75 Amps → AWG 6

Properties and Benefits of AWG 4 Wire

Considering these parameters, AWG 4 wire is the safest selection for a 50-amp current. Below are its critical properties:

• - Diameter: 0.2043 inches (5.189 mm)
• - Area: 0.0308 square inches (41.7 kcmil, 21.1506 mm²)
• - Resistance: 0.2485 milliohms/foot (0.8152 milliohms/meter)
• - Current-carrying capacity:
• - 70 amps @60°C/140°F
• - 85 amps @75°C/167°F
• - 95 amps @90°C/194°F

Despite AWG 4 wire being thicker, heavier, and somewhat cumbersome, its advantages include:

• - Reduced energy loss
• - Lower wire temperature

Professionals frequently prioritize AWG 4 wiring for its reliability and long-term safety, ensuring efficient system operation without overheating risks.

50-Amp Circuit Breaker

Choosing the right 50-amp circuit breaker entails more than merely matching the amperage.

Ensure you do not use under-amperage breakers. A breaker rated below 50 amps will not only trip frequently but could also damage electrical components, leading to increased wear and tear on the breaker itself. Over time, this persistent issue may result in higher expenses and elevated dangers.

When considering the length of the electrical circuit, AWG 4 copper wire is suitable for 50-amp circuits spanning distances between 30 to 100 feet (9.2 to 30 meters). This ensures adequate current flow and minimizes overheating risks.

For shorter cable lengths, AWG 6 wire might be employed. However, it is pertinent to consider that AWG 6 wire operates at a higher temperature, which may not be ideal for all environments.

In summary:

• - Use AWG 4 copper wire for 50-amp circuits with cable lengths ranging from 30 to 100 feet.
• - For shorter distances, AWG 6 wire could be an option, contingent upon the consideration of operating temperatures.
• - Always seek professional advice to fully ensure safety and compliance with regulatory standards.