Current Carrying Capacity of Copper Wire

Current Carrying Capacity of Copper Wire

AWG Size Dielectric/ Copper Wire Temperature
@ 105°C @ 80°C @ 125°C @ 90°C @ 200°C
26 5 4 6 5 7
30 3 2 3 3 4
24 7 6 8 7 10
28 4 3 5 4 6
20 13 10 14 12 17
22 10 8 11 9 13
16 24 29 26 22 32
18 18 15 20 17 24
12 45 36 50 40 55
14 33 27 40 30 45
10 58 47 70 55 75

Table of contents

Key Determinants of Current Carrying Capacity of Copper
Conductors

Bare Copper Conductor Current Carrying Capacity Factors

Cpper Wire Size & Amp Ratings

Aluminum Copper
Wire Gauge Size 90°C (194°F)
XHHW-2, THHN,
THWN-2		 75°C (167°F)
THW, THWN,
SE, USE, XHHW		 75°C (167°F)
THW, THWN,
SE, USE, XHHW		 60°C (140°F)
NM-B, UF-B		 90°C (194°F)
THWN-2, THHN,
XHHW-2, USE-2
750 435 385 475 — 535
14 — — 20 15 25
300 260 230 285 — 320
8 45 40 50 40 55
350 280 250 310 — 350
12 25 20 25 20 30
6 55 50 65 55 75
1000 500 445 545 — 615
10 35 30 35 30 40
3 85 75 100 85 115
4 75 65 85 70 95
500 350 310 380 — 430
1 115 100 130 — 145
600 385 340 420 — 475
2 100 90 115 95 130
2/0 150 135 175 — 195
4/0 205 180 230 — 260
1/0 135 120 150 — 170
250 230 205 255 — 290
3/0 175 155 200 — 225

Temperature Rating of 2000 Volts Copper Conductor for 90, 75 and 60°C

Size Temperature Rating of Copper (Cu)Conductor
(AWG or kcmil) 75°C (167°F) 60°C (140°F) 90°C (194°F)
12 AWG* 25   30
1500 KCMIL 625 525 705
2/0 AWG 175 145 195
1750 KCMIL 650 545 735
18 AWG — — 14
700 KCMIL 460 385 520
4 AWG 85 70 95
800 KCMIL 490 410 555
10 AWG* 35 30 40
16 AWG — — 18
750 KCMIL 475 400 535
3 AWG 100 85 115
900 KCMIL 520 435 585
2 AWG 115 95 130
1000 KCMIL 545 455 615
1250 KCMIL 590 495 665
8 AWG 50 40 55
350 KCMIL 310 260 350
600 KCMIL 420 350 475
6 AWG 65 55 75
400 KCMIL 335 280 380
4/0 AWG 230 195 260
300 KCMIL 285 240 320
3/0 AWG 200 165 225
500 KCMIL 380 320 430
1/0 AWG 150 125 170
250 KCMIL 255 215 290
14 AWG* 20   25
1 AWG 130 110 145
2000 KCMIL 665 555 750

Single Insulated Copper Conductors Current Carrying Capacity

Size Temperature Rating of Copper Conductor
(AWG or kcmil) 90°C (194°F) 60°C (140°F) 75°C (167°F)
10 AWG* 55   50
600 KCMIL 780 575 690
4 AWG 140 105 125
500 KCMIL 700 515 620
3/0 AWG 350 260 310
8 AWG 80 60 70
700 KCMIL 850 630 755
2 AWG 190 140 170
400 KCMIL 615 455 545
800 KCMIL 920 680 815
6 AWG 105 80 95
250 KCMIL 455 340 405
1/0 AWG 260 195 230
3 AWG 165 120 145
900 KCMIL 980 730 870
1 AWG 220 165 195
300 KCMIL 500 375 445
2/0 AWG 300 225 265
350 KCMIL 570 420 505
4/0 AWG 405 300 360
750 KCMIL 885 655 785
1000 KCMIL 1055 780 935
1250 KCMIL 1200 890 1065
1500 KCMIL 1325 980 1175
1750 KCMIL 1445 1070 1280
2000 KCMIL 1560 1155 1385
Current-carrying Capacity From 4 to 41 Copper Conductors
Number of current carrying conductors* Percent of values in tables for ambient temperature
41 and more 35
31 – 40 40
21 – 30 45
10 – 20 50
7 – 9 70
4 – 6 80
Current-Carrying Capacity for Ambient Temperatures
Ambient Temperature 75°C
(167°F)		 60°C (140°F) 90°C
(194°F)
16 to 20°C 60-68°F 1.11 1.15 1.08
10°C or less 50°F or less 1.20 1.29 1.15
21 to 25°C 69-77°F 1.05 1.08 1.04
11 to 15°C 51-59°F 1.15 1.22 1.12
31 to 35°C 87-95°F 0.94 0.91 0.96
26 to 30°C 78-86°F 1.00 1.00 1.00
41 to 45°C 105-113°F 0.82 0.71 0.87
36 to 40°C 96-104°F 0.88 0.82 0.91
51-55°C 123-131°F 0.67 0.41 0.76
46-50°C 114-122°F 0.75 0.58 0.82
61-65°C 141-149°F 0.47 – 0.65
56-60°C 132-140°F 0.58 – 0.71
71-75°C 159-167°F – – 0.50
66-70°C 150-158°F 0.33 – 0.58
81-85°C 177-185°F – – 0.29
76-80°C 168-176°F – – 0.41

Annealed Bare Copper Wire Specification

Specification
Types of Current Copper Wire Carries

A.C. Alternating Current

D.C. Direct Current

Temperature 30°C (86°F)
Benefits

Reduce the risk of overheating

maintain current carrying capacity

Bundled Conductors Derating Factors

Bundle Derating Factor (X Amps)
2-5 0.8
16-30 0.5
6-15 0.7

Methods to Calculate the Cable and Current Carrying Capacity

  • Ampacity Tables
  • Derating Factors
  • Temperature Ratings
  • Heat Generation and Dissipation
  • Engineering Calculations
  • Standards and Codes
  • Software Tools

Current Density of Copper Per sq mm

Anamalled Copper Wire 3.5 A/Sq mm
Copper Conduits 2.8A/Sq mm
Imbedded in Ground 2A/Sq mm
Cable in ventilated tray 3.0 A/Sq mm
Naked Copper Wire 4.5 A/Sq mm

Max Current Density of Aluminium and Copper Conductors

  • Aluminium: Up to 3.5 A/mm²
  • Copper: Up to 3.5 A/mm²

Formula for The Current Carrying Capacity

Current Carrying Capacity Formula

Details
Formula Current (I)=Voltage (V)Resistance (R)\text{Current
(I)} = \frac{\text{Voltage (V)}}{\text{Resistance (R)}}
Known as Ohm’s Law
Current (I) Measured in Amperes (A)
Voltage (V) Measured in Volts (V)
Resistance (R) Measured in Ohms (Ω)
Relationship Current is directly proportional to Voltage and inversely
proportional to Resistance

Current Capacity of an Aluminium and Copper Conductor

Cond. Area in MM Aluminum Conductor Copper Conductor
1.5 13 16
4.0 23 25-32
2.5 18 20-25
10.0 40 63
6.0 30 40
25 70 129
16 51 98
50 105 198
35 86 158
95 155 292
70 130 245
150 205 391
120 180 344
240 280 528
185 240 448
400 375 726
300 315 608
500 585 830

Standards of Bare Copper Conductor Current Carrying
Capacity

  • IEC 60228
  • BS EN 60228

Copper Conductor Ampacity Charts

Copper (Wire Size & Amp Ratings)
Wire Gauge Size 60°C (140°F)
NM-B, UF-B		 75°C (167°F)
THW, THWN,
SE, USE, XHHW 		90°C (194°F)
THWN-2, THHN,
XHHW-2, USE-2
14 15 20 25
12 20 25 30
10 30 35 40
8 40 50 55
1 — 130 145
1/0 — 150 170
2/0 — 175 195
3/0 — 200 225
6 55 65 75
4 70 85 95
3 85 100 115
2 95 115 130
4/0 — 230 260
250 — 255 290
300 — 285 320
750 — 475 535
1000 — 545 615
350 — 310 350
500 — 380 430
600 — 420 475

Current Carrying Capacity of Copper Wire Per sq mm Chart

Nominal CrossSection (mm²) Group 1 Group 2 Group 3
Current Carrying Capacity(A) Copper Wire Protective Fuse(A) Current Carrying Capacity(A) Copper Wire Protective Fuse(A) Current Carrying Capacity(A) Copper Wire Protective Fuse(A)
0,75   12 6 15 10
1 11 6 15 10 19 16
1,5 15 10 18 16 24 20
6 33 25 44 32 54 50
10 45 32 61 50 73 63
16 61 50 82 63 98 80
25 83 63 108 80 129 100
2,5 20 16 26 20 32 25
4 25 20 34 25 42 32
35 103 80 135 100 158 125
50 132 100 168 125 198 160
120 235 200 292 250 344 315
150     335 250 391 315
185     382 315 448 400
70 165 125 207 160 245 200
95 197 160 250 200 292 250
240     453 315 528 400
300     504 400 608 500
400         726 630
500         830 630

Current Carrying Capacity Of Aluminium Cable

Current Carrying Capacity Of Aluminium Cable

Class 2 Copper Wire Diameter Chart & Properties

NO. OF WIRES NOMINAL CROSSSECTIONAL AREA (mm²) DIAMETER OFCONDUCTORSmm DIAMETER OF WIRES (mm) MECHANICAL PROPERTIES OFPLAIN COPPER WIRE MAXIMUM DCRESISTANCEAT 20°(ohms/km) NOMINALWEIGHT(kg/km)
Minimum Elongation% Minimum TensileStrength(N/mm2)
7 16 4.8 1.74 28 200 1.15 137
7 25 5.8 2.19 28 200 0.727 215
7 1.5 1.59 0.53 24 200 12.1 13
7 10 3.85 1.35 26 200 1.83 87
7 35 6.9 2.62 28 200 0.524 300
10 50 8.2 2.62 28 200 0.387 410
7 2.5 2.01 0.67 24 200 7.41 21
7 4 2.55 0.85 24 200 4.61 35
7 6 3.15 1.05 26 200 3.08 52
14 70 9.7 2.62 28 200 0.268 595
19 95 11.4 2.62 28 200 0.193 820
48 240 18.6 2.62 28 200 0.0754 2100
61 300 20.4 2.62 28 200 0.0601 2700
19 120 13.1 2.62 28 200 0.153 1040
37 150 14.2 2.62 28 200 0.124 1280
37 185 15.8 2.62 28 200 0.0991 1600
61 400 26 3 33 200 0.047 3400
61 500 30 3 33 200 0.0366 4400

Amperes Conductor Chart

Insulation Materials: Copper Temp. 30 AWG 28 AWG 26 AWG 24 AWG 22 AWG 20 AWG 18 AWG 16 AWG 14 AWG 12 AWG 10 AWG 8 AWG 6 AWG 4 AWG 2 AWG
Polyethylene
Neoprene Polyurethane
Polyvinylchloride
(Semi-Rigid)		 80°C 2 3 4 6 8 10 15 19 27 36 47 65 95 125 170
Polypropylene Polyethylene(High Density) 90°C 3 4 5 7 9 12 17 22 30 40 55 70 100 135 180
Polyvinylchloride PVC (Irradiated) Nylon 105°C 3 4 5 7 10 13 18 24 33 45 58 75 105 145 200
Kynar (135°C)
Polyethylene(Crosslinked)
Thermoplastic
Elastomers		 125°C 3 5 6 8 11 14 20 26 40 50 70 90 125 170 225
Kapton
PTFE
FEP
PFA
Silicone		 200°C 4 6 7 10 13 17 24 32 45 55 75 100 135 180 240

Wire Gauge Chart

BWG (UK Sizes) Thickness (in) Thickness (mm) AWG (US Size) Thickness (in) Thickness (mm)
30 0.0124 0.315 30 0.01 0.255
0 0.5 12.7 0 0.325 8.252
10 0.1406 3.569 10 0.12 3.048
24 0.022 0.559 24 0.0201 0.511
28 0.0148 0.376 28 0.0126 0.321
22 0.028 0.711 22 0.025 0.634
6 0.238 6.045 6 0.192 4.877
14 0.083 2.108 14 0.072 1.829
26 0.018 0.457 26 0.0159 0.405
18 0.048 1.219 18 0.0403 1.024
2 0.375 9.525 2 0.289 7.348
20 0.036 0.914 20 0.032 0.813
16 0.0625 1.588 16 0.0508 1.291
0 0.75 19.05 0 0.46 11.684
12 0.109 2.769 12 0.094 2.392
8 0.18 4.572 8 0.148 3.759
0 0.625 15.875 0 0.375 9.525
4 0.3 7.62 4 0.22 5.588

Copper Cable Ampacity Chart

SUGGESTED AMPACITIES
AMPERES PER CONDUCTOR
AWG 105°C 80°C 125°C 90°C 150°C 250°C* 200°C
30 3 2 3 3 3 4 4
24 7 6 8 7 8 11 10
28 4 3 5 4 5 6 6
20 13 10 14 12 15 19 17
26 5 4 6 5 6 8 7
18 18 15 20 16 22 29 24
22 10 8 11 9 12 14 13
14 33 20 40 25 40 39 45
16 24 18 26 20 29 37 32
10 58 35 70 40 70 73 75
12 45 25 50 30 50 54 55

Current Carrying Capacity of 0.5 Sq Mm Copper Wire for Single Core

For pvc non-armoured copper cable
Conductor Clipped Direct to a Surface or on a Cable TrayBunched or
Unenclosed		 Bunched & Enclosed in Conduit or Trunking
Nominal Cross-Sectional Area (mm²) No. and Diameter of Wires Current Rating (A) Volt Drop per Amp per Metre (mV) Current Rating (A) Volt Drop per Amp per Metre (mV) Current Rating (A) Volt Drop per Amp per Metre (mV) Current Rating (A)
2.5 Sq mm 1/1.78 16 23 14 20 16 18 14
1.0 Sq mm 1/1.13 40 13 35 12 40 11 35
4 Sq mm 7/0.85 10 30 8.8 27 10 24 8.8
1.5 Sq mm 1/1.38 27 16 23 15 27 13 23
10 Sq mm 7/1.35 4.0 51 3.5 46 4.0 42 3.5
6 Sq mm 7/1.04 6.8 38 5.9 34 6.8 31 5.9
25 Sq mm 7/2.14 1.6 89 1.4 80 1.6 73 1.4
16 Sq mm 7/1.70 2.6 68 2.2 61 2.6 56 2.2
50 Sq mm 19/1.78 0.93 175 0.82 160 0.97 145 0.84
35 Sq mm 19/1.53 1.2 109 1.0 98 1.2 90 1.0
95 Sq mm 19/2.52 0.48 270 0.45 240 0.56 230 0.48
70 Sq mm 19/2.14 0.65 220 0.59 200 0.71 185 0.62

Twin and Multicore with Current Rating Copper Conductor

Conductor Clipped Direct to a Surface unenclosed Enclosed in Conduit or Trunking
Nominal Cross-Sectional Area No. and Diameter of Wires One Three-Core Cable one 4-core 3-phase One Twin Cable Single-Phase A.C. or D.C. One Three Core Cable conductor, 4 core, One Twin Cable Conductor, Single-Phase A.C. or D.C.
Volt Drop per amp. per metre* Current Rating Volt Drop per amp. per metre* Current Rating Volt Drop per amp. per metre* Current Rating Volt Drop per amp. per metre* Current Rating
mm2 mm mV A mV A mV A mV A
2.5 + 1/1.78 16 21 14 18 14 16 16 18
10 + 7/1.35 4 48 3.5 41 3.5 37 4 40
6 + 7/1.04 6.8 35 5.9 30 5.9 27 6.8 30
1.0 + 1/1.13 40 12 35 10 35 9 40 11
4 + 7/0.85 10 27 8.8 24 8.8 22 10 24
16 + 7/1.70 2.6 64 2.2 54 2.2 47 2.6 53
1.5 + 1/1.38 27 15 23 13 23 12 27 13
35 ++ 19/1.53 1.2 87 1 72 1 65 1.2 74
25 ++ 7/2.14 1.7 71 1.5 62 1.5 53 1.7 60

Copper Wire Current Carrying Capacity for 1.5MM2 to 3.5MM2

Conductor Defined Conditions Clipped Direct to a Surface or on aCable Tray, and
Unenclosed
Construction Nominal Area One Twin Cable, Single-Phase A.C. / D.C. Four-Core or One Three Cable, Three Phase Four-Core or One Three Cable, Three Phase One Twin Cable, Single-Phase A.C. / D.C.
Volt Drop /Amp. Per m* Current Rating Volt Drop Per m* per Amp. Current Rating Volt Drop Per m* per Amp. Current Rating Volt Drop Per m* per Amp. Current Rating
mm mm2 mV A mV A mV A mV A
7/0.85 4 – – – – 11 26 9.1 22
1/1.38 1.5 – – – – 28 14 24 13
7/1.04 6 7 38 6 32 7 32 6 28
3/1.04 2.5 – – – – 17 20 15 17
7/1.70 16 2.6 68 2.2 58 2.6 58 2.2 50
7/1.35 10 4.1 52 3.6 44 4.1 45 3.6 38
19/1.53 35 1.2 112 1 94 1.2 93 1 80
7/2.14 25 1.7 91 1.5 77 1.7 76 1.5 66

Current Capacity Copper Wire for 50MM2 to 400MM2

Conductor Defined Conditions Clipped Direct to a Surface or on a Cable Tray, and
Unenclosed
Nominal Area Construction One Twin Cable Four Core Cable Single Phase A.C. or D.C. Three or FourCore Cable
Current Rating Volt Drop per Amp. Per meter* Volt Drop per Amp. Per meter* Current Rating Current Rating Volt Drop per Amp. Per meter* Volt Drop per Amp. Per meter* Current Rating
D.C. A.C. D.C. A.C.
mm2 mm amp mV mV mV amp amp mV mV mV amp
50 19/1.78 180 0.92 0.92 0.81 155 150 0.92 0.92 0.81 125
70 19/2.14 220 0.64 0.65 0.57 190 180 0.64 0.65 0.57 155
95 19/2.52 270 0.46 0.48 0.42 230 225 0.46 0.48 0.42 190
120 37/2.03 310 0.36 0.4 0.34 270 260 0.36 0.4 0.34 220
150 37/2.25 355 0.25 0.32 0.29 310 290 0.25 0.32 0.29 250
185 37/2.52 410 0.23 0.29 0.24 350 340 0.23 0.29 0.24 290
240 61/2.25 485 0.18 0.25 0.2 420 400 0.18 0.25 0.2 350
300 61/2.52 550 0.14 0.23 0.18 475 460 0.14 0.23 0.18 400
400 61/2.85 620 0.11 0.22 0.17 550 520 0.11 0.22 0.17 460

Current Ratings Wire Gauge Sizes

AWG Diameter
(in)		 Diameter
(mm)		 Square
(mm2)		 Resistance
Aluminum (ohm/1000ft)
(ohm/1000m)		 Typical Maximum. Current Load Ratings Copper amps
Multicore
4 – 6 cores up to 3 cores 25 – 42 cores 25 – 42 cores 7 – 24 cores
34 0.0063 0.16 0.020 1325
2 0.26 6.5 33.6 0.79 76 95 57 57 66
3 26.7 0.99 64 80 48 48 56
24 0.020 0.51 0.20 133 1.6 2 1.2 1.2 1.4
35 0.0056 0.14 0.015 1767
28 0.013 0.33 0.080 331
32 0.0080 0.20 0.031 855
8 0.13 3.3 8.3 3.2 32 40 24 24 28
26 0.016 0.41 0.13 204
1 0.29 7.4 42.4 0.63 88 110 66 66 77
27 0.014 0.36 0.096 276
4 0.20 5.2 21.2 1.3 56 70 42 42 49
18 0.040 1.0 0.82 32 5.6 7 4.2 4.2 4.9
16 0.051 1.3 1.3 20 8.0 10 6.0 6.0 7.0
25 0.018 0.45 0.16 166
13 0.072 1.8 2.6 10
22 0.025 0.64 0.33 80 2.4 3 1.8 1.8 2.1
20 0.032 0.81 0.50 53 4.0 5 3.0 3.0 3.5
10 0.10 2.6 5.3 5.0 24 30 18 18 21
14 0.064 1.6 2.1 13 12 15 9.0 9.0 10
6 0.17 4.1 13.3 2.0 44 55 33 33 38
12 0.081 2.1 3.3 8.0 16 20 12 12 14

Current Carrying Capacity Copper Wire Temperature Rating

Ambient Temp (C) Ambient Temp(F) 450C 250C 200C
61-70 142-158 0.96 0.93 0.90
41-50 106-122 0.99 0.98 0.97
81-90 177-194 0.93 0.87 0.83
51-60 124-140 0.99 0.95 0.94
91-100 195-212 0.92 0.85 0.72
71-80 160-176 0.95 0.90 0.87
121-140 249-284 0.86 0.71 0.61
101-120 213-248 0.89 0.79 0.71
161-180 321-356 0.81 0.58 0.35
141-160 285-320 0.84 0.65 0.50
201-225 393-437 0.74 0.35 –
181-200 357-392 0.78 0.49 –
251-275 483-527 0.65 – –
226-250 439-482 0.69 – –
301-325 573-617 0.55 – –
176-300 528-572 0.60 – –
351-375 663-707 0.42 – –
326-350 618-662 0.49 – –
376-400 708-752 0.34 – –

American Wire Gauge Sizes

American Wire Gauge Sizes

AWG Diameter (mm) Diameter (in) Area (mm²) Resistance (Ω/km) Resistance (Ω/1000 ft) Max Frequency (Hz) Max Current (A)
000 (3/0) 10.40384 0.4096 85 0.202704 0.0618 160 239
0000 (4/0) 11.684 0.46 107 0.16072 0.049 125 302
0 (1/0) 8.25246 0.3249 53.5 0.322424 0.0983 250 150
00 (2/0) 9.26592 0.3648 67.4 0.255512 0.0779 200 190
3 5.82676 0.2294 26.7 0.64616 0.197 500 75
1 7.34822 0.2893 42.4 0.406392 0.1239 325 119
4 5.18922 0.2043 21.2 0.81508 0.2485 650 60
2 6.54304 0.2576 33.6 0.512664 0.1563 410 94
6 4.1148 0.162 13.3 1.295928 0.3951 1100 37
5 4.62026 0.1819 16.8 1.027624 0.3133 810 47
8 3.2639 0.1285 8.37 2.060496 0.6282 1650 24
7 3.66522 0.1443 10.5 1.634096 0.4982 1300 30
10 2.58826 0.1019 5.26 3.276392 0.9989 2600 15
9 2.90576 0.1144 6.63 2.598088 0.7921 2050 19