General Amperage Table | Insulation melting point amps | Low Voltage Types | Coaxial Cable | Speaker Wire

Conductor size is based one or more of the following considerations:
Current carrying capacity [inducing a rise in wire temperature, in high-voltage lines], Short circuit current, or Voltage drop [long low voltage lines].

Current carrying capacity varies depending on the type of insulation, current and use.

American wire gage every 6 gauge decrease gives a doubling of the wire diameter, and every 3 gauge decrease doubles the wire cross sectional area.

The wire size is dependent on amperage not voltage. The NEC code is for household AC power wiring, the others are generally for DC, but they should be about the same.
Conductor
Size (AWG)
Maximum Amperage Diameter (in) Resis-
tance

ohm/
1000'
*
NEC prem-
ises †
NEC General ‡ ARRL2 TFE insulated3 Chassis wiring1 Power Trans-
mission 1
stranded Solid
Bun-
dled 140°F insl.
Single 194°F insl. Bun-
dled
Single Bun-
dled
Single
0000 4/0   195 405     380   302     0.46 0.05
00 2/0 200 145 300     87 169 283 190   0.36 0.08
0   110 220     75 147 245 150 0.38 0.32 0.1
1 150 95 190         211 119 0.33 0.29 0.13
2   85 165     50 108 181 94 0.3 0.26 0.16
4 100 70 140     40 81 135 60 0.24 0.2 0.25
6 50 55 105     30 60 101 37 0.19 0.16 0.4
8 40 40 80     23 44 73 24 0.15 0.13 0.64
10 30 30 55     16 33 55 15 0.12 0.1 1.02
12 20 25 40 23 41 12 25 41 9.3 0.09 0.08 1.62
14 15 20 35 17 32 8 19 32 5.9 0.07 0.06 2.58
16   - 24 13 22 6 13 22 3.7 0.06 0.05 4.08
18   - 18 10 16 5 9.2 16 2.3 0.05 0.04 6.52
20       7.5 11 3.7 6.5 11 1.5 0.04 0.03 10.36
22       5 7 2.5 4.5 7 0.92   0.03 16.46
24           2 3.3 3.5 0.58   0.02 25.67
30           0.7 1.3 0.86 0.14   0.01 103.2
AWG - American Wire Gauge

Wire Size Specifications [NEC Table: UL486E]
Also National Fire Protection Association (NFPA 70)
- Cable sizing for premises wiring.
Wire must be two sizes larger (lower AWG) for Aluminum Wire.
‡ NEC Article 310 Conductors for General Wiring. (2008 Edition)
There two tables in this article one for bundled conductors and one for free air conductors. Each has three voltage ranges for insulation with different melting temperatures.
We used the low (60°C insulation bundled) and high (90°C insulation free air) values.
- Table 310.17 - Allowable Ampacities of Single-Insulated Conductors Rated 0 Through 2000 Volts in Free Air, Based on Ambient Air Temperature of 30°C (86°F)
- Table 310.16 - Bundled cables
Insulation temperature ratings:

  • 60°C (140°F): Types TW, UF
  • 75°C (167°F): Types RHW, THHW, THW, THWN, XHHW, ZW
  • 90°C (194°F): Types TBS, SA, SIS, FEP, FEPB, MI, RHH, RHW-2, THHN, THHW, THW-2, THWN-2, USE-2, XHH, XHHW, XHHW-2, ZW-2

These tables also contain correction factors for ambient temperatures higher than 30°C ((86°F):
60°C (140°F): 0.6 (ie. max. amps is 60% the value above)
75°C (167°F): 0.4

1 - Handbook of Electronic Tables and Formulas for American Wire Gauge, H.W. Sams and Co., 6th edition (March 1986)
The Maximum Amps for Power Transmission uses the 700 circular mils per amp rule, which is very very conservative.
Chassis Wiring is meant for wiring in air, and not in a bundle.

2 - ARRL - Amateur Radio Relay League Handbook.
Based on max. wire temperature 100° C with ambient temperature 57° F

* Stranded wire

3 - MIL-STD-975 replaced by the NASA Parts Selection List. (NPSL)

The suggested MAXIMUM fuse rating is no MORE than 50% of the maximum current load a wire can handle.


Extension Cords
The NEC sets limits on the amount of current that cords are permitted to carry. This is for safety, to prevent overheating the cord. The limits for common cords are given under NEC premises in the chart above.
See the Extension Cord Page for size and length specifications to avoid excessive voltage drop.

Jump Starting Cables
Although most car battery ratings in Cold Cranking Amps (CCA) are from 540-880 CCA, a jump start cable only needs to support 85-150 Amps.
See Jump Starting


Auto Audio: (Crutchfield) Maximum Amplifier draw.
AMPS Length ft
≤7 7-10 10-13 13-16
50-65 10 8 8 4-6
68-85 8 8 4-6 4
85-105 8 4-6 4 4
105-125 8 4-6 4 4
125-150 4-6 4 4 2
Source: How to determine the best wire gauge
Auto Audio: (Car Audio Help)
AMPS Length ft
≤7 7-10 10-13 13-16
50-65 8 6 4 4
68-85 6 4 4 2
85-105 6 4 2 2
105-125 4 4 2 2
125-150 2 2 2 0
Source: Car Audio Wiring | CarAudioHelp.com

Allowable Amperage Of Current Carrying Conductors Under 50V As Suggested By The American Boat And Yacht Council (ABYC)
Allowable amperage of single conductors rated 105C - Outside / Inside of Engine Space
AWG Amps
Outside Inside
18 20 17
16 25 21
14 35 30
12 45 38
10 60 51
8 80 68
6 120 102
4 160 136
2 210 178
1 245 208
1/0 285 242
2/0 330 280
4/0 445 378
Source: Marine Wire Size - Marine Wire and Cable

American specs covering automotive wire are SAE J 1127 and J-1128, specifying resistance to heat and mechanical damage.
There are two basic types of insulation covered in these specs: Polyvinyl Chloride, (PVC ), and Cross-linked Polyethylene, (XPE).
GPT, TWP, and HDT wire insulations are all Polyvinyl Chloride (PVC) based insulations used in cooler parts of the car with a 185°F/85°C rating.
SXL, GXL, and TXL (thin, medium, and thick insulation) wire are Cross-linked Polyethylene, (XLP) and used under the hood. They have a 257°F/125°C temperature rating.


Maximum current capacity depends on the melting temperature of the insulation.
TFE - Tetrafluorethylene.
Teflon TFE- Teflon a DuPont trademark.
PTFE - Polytetrafluoroethylene
ETFE - Ethylene Tetrafluoroethylene
  Insulation Type
Conductor
Size
Polyethylene
Neoprene
Polyurethane
Polyvinylchloride
(Semi-Rigid)
Poly-
propylene
Polyethylene
(High Density)
Polyvinyl-
chloride
PVC
(Irradiated)
Nylon
Polyethylene
(Crosslinked)
Thermoplastic
Elastomer
Kapton
Teflon
Silicone
Max
Temp
80° C 90° 105° 125° 200°
176° F 194° 221° 257° 392°
AWG Maximum Current - Amps
2 170 180 200 225 240
4 125 135 145 170 180
6 95 100 105 125 135
8 65 70 75 90 100
10 47 55 58 70 75
12 36 40 45 50 55
14 27 30 33 40 45
16 19 22 24 26 32
18 15 17 18 20 24
20 10 12 13 14 17
22 8 9 10 11 13
24 6 7 7 8 10
26 4 5 5 6 7
28 3 4 4 5 6
30 2 3 3 3 4
Source: Alpha Wire High ambient temperature increases the chance of insulation meltdown, so max. amperage is reduced. De-rating for high temperature:
Copper Wire Correction
Temperature 40°C 45°C 50°C 55°C 60°C 70°C
104°F 113°F 122°F 131°F 140°F 158°F
DerateAmpacity 0.88 0.82 0.75 0.67 0.58 0.33
Low Voltage Cable Types
MP - Multipurpose cable
CM - Communications Cable
PLTC - Power-limited tray cable
Article 725, Class 2
   725-38(b)1      CL2X    Class 2 cable, limited use
   725-38(b)1      CL2     Class 2 cable
   725-38(b)2      CL2R    Class 2 riser cable
   725-38(b)3      CL2P    Class 2 plenum cable
   
Class 2, Class 3 - Remote-control, signaling, and power-limited cables
Class 1 - Power and lighting cables
FPL - Power-limited fire protective signaling cables 
Maximum Power Supply size for Class 2 Circuits is 100 VA

Anderson Powerpole Connectors:
The Anderson Power Multipole Connectors are color coded with mechanical voltage keys to prevent mismatching power supplies and electrical outlets. Flat wiping contacts clean the contact surface during disconnection and allow for minimal contact resistance at high current. The Multipole Connectors are genderless housings that are capable of 10,000 mating cycles.
The 30-amp Anderson Powerpole connector is being adopted by ARES & RACES groups nationwide. Products:
  Housing  Contact
PP15/30/45: 30A, 600V AWG #16 to #12 -The standard for amateur radio
PP15/30/45: 45A, 600V AWG #14 to #10
PP75:       75A, 600V AWG #16 to #6
    You order contacts separately #6, #8, #10, #10/12
 

Standard Powerpole® Family at andersonpower.com
Anderson Power Poles, Connectors & Housings | Powerwerx
Powerpoles and Related Hardware | qsradio.com
Anderson Power Connectors at Solar-Electric
Anderson Power Products | Anderson Power Products Distributor : Mouser.com

Anderson Powperpole IDEAS at buck0
Anderson Powerpole Instructions | wb3w.net
Notes at San Antonio Hams

DC Power distribution Pannels:
eHam.net Reviews - DC Power Supply Distribution Panels
RIGrunner 4012 West Mountain Radio

See:
Coaxial Cable
Power Requirements of appliances
American Wire Gauge (AWG) and Current Limits
DC connectors - Wikipedia
Copper wire
Car Audio Wiring
Wire Size Chart at OmenTrance.com
AWG Cable Description
Glossary
2002 NEC
Electrical Code Basics
Copper Wire characteristics
Wire Gauge and Current Limits at Power Stream
Amateur Radio Wiring at k0bg.com
Copper Wire Figures ata EPanorama.net


last updated 16 Mar 2006