The table below lists the wire characteristics for different gauge sizes of
the American Wire Gauge [AWG].
The American Wire Gauge provides a means of specifying wire diameters.
For each different AWG [wire size] the table provides the Diameter [in mils], the resistance per 1000 foot,
the current carrying capability [Ampacity], and Pounds per Foot [number of feet required to weigh 1 pound].
The AWG is based upon a constant ratio of cross-section between wires of successive gauge sizes [numbers].
Read the notes below the table to determine how the Ampacity was derived. The larger the AWG wire gauge number, the smaller diameter of the wire.
The table is based on an ambient temperature of 25oC. However the next link provides additional temperatures.
Some of the standard wire sizes used in a number of Interface Buses [for data lines] are #22AWG, #24AWG, #26AWG, and 30AWG.
Refer here for a quick guide to Wire Gauge by Resistance Table. A listing of Electronic bus standards are located on the Buses page.
Another table near the bottom of the page provides copper current carrying ability [Ampacity] for Teflon insulated wire. Related; Cable Derating.
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].
|AWG||Diam. (mils)||Circular mils||Ohms/1000ft||Current Carrying||Fusing Current||Feet per Pound|
The wire size is different between the American Wire Gage [AWG] and the British standard. The table above only lists the AWG standard.
AWG [American Wire Gauge] may also be called the Brown and Sharpe (B&S) Wire Gauge, but would be an extremely out-dated reference. See the B&S note below.
The Birmingham Wire Gauge [BWG] is used for steel armor wire, as opposed to copper wire. [other wire gauge standards]
Watch for round-off errors, as many numbers were rounded. Use the table as a guide. [equivalent Cross-Sections of Wire]
The wire weight [pound per foot] provided does not include wire insulation, a jacket or any shielding as that would imply a cable and not a wire.
The weight of the wire is critical in some applications; for example, aircraft cabling. More data [AWG Table for 25C - 65C]
Circular mils is the diameter squared in mils. [Table of AWG sizes in metric]
The editor has never reviewed the American Wire Gauge [AWG] standard.
IEEE Standard 835, IEEE Standard Power Cable Ampacity Tables
IEEE Standard 848, Procedure for the Determination of the Ampacity Derating of Fire Protected Cables
ICEA P-54-440, NEMA Pub. No. WC 51 - Ampacities of Cables in Open-Top Trays.
The National Electrical Code [NEC] requires their own cable sizing for premises wiring.
Refer to the NEC rules to determine building wiring, as this page relates to electronic equipment wiring.
For reference, the ampacity of copper wire at 300C for common wire sizes
14 AWG may carry a maximum of 20 Amps in free air, or 15 Amps as part of a 3 conductor cable.
12 AWG may carry a maximum of 25 Amps in free air, or 20 Amps as part of a 3 conductor cable.
10 AWG may carry a maximum of 40 Amps in free air, or 30 Amps as part of a 3 conductor cable.
8 AWG may carry a maximum of 70 Amps in free air, or 50 Amps as part of a 3 conductor cable.
Hook-up Wire Current Capacity [short wire runs between components or parts contained in equipment].
Control Cable Current Capacity [electrical power equipment cable].
The wire fusing [melting] current is based on the material the wire is made of, the diameter of the wire and the melting point of the the material.
The wire fusing current of a wire is provided in tables as constant current or as [a larger] current for some given amount of time.
I found this formula used on a few different sites [un-verified]; I=Ad(3/2) @ d is in inches, A is a constant: A = 10,244 for Copper. A = 7,585 for Aluminum.
I have listed a number of values for fusing current in the table above, for selected AWG sizes.
Aluminum wire properties are listed under on the Aluminum Wire gauge Table page
also Monel wire gauge chart, and Nichrome wire gauge chart
Electrical Wire and Cable Manufacturers for a list of wire companies
The graphic below will answer the question how much current can wire handle, safely, but it only applies to single wires, as in wire gauge ampacity.
Adding more wires inside an insulator will trap more heat and force the cable handle less current, by design.
Note the graphic does not address wire length.
Cable manufacturers will provide different numbers based on the
insulation used for the wire.
|AWG Wire Gauge||Current Carrying||AWG Wire Gauge||Current Carrying|
|00||169 amps||0||147 amps|
Refer to the How to Derate
Components page for derating wire with other then Teflon
I have seen one other Military Specification [MIL-STD-xx] for copper wire current capability. That standard [I did not note the standard number] listed AWG 18 [for example] as 10 amps with TFE insulation. That indicates that this additional military specification uses the same data listed in the table above, but may be listed for 250C, and not 700C as the table uses. So this table above has already been derated for 700C.
This page provides a conservative guide for Ampacity for bare copper wire [700 Circular mils/amp] , the melting [point] current for bare copper wire, and the Ampacity for TFE coated copper wire. The American Wire Gage [AWG] for bare copper wire is also listed. Refer to the National Electrical Code [NEC] to determine cable sizing for premises wiring.
This page represents my notes on the subject, purchase one of the standards or specifications referenced on this page when doing professional work.
Also see the Wire Insulation Color Code page; Color coding of wire insulation based on application.
Determine cable length vs. voltage drop. Determine cable length vs. Heat increase.
With any topic there are a number of different ways to describe the same thing;
AWG, Wire Gauge, Wire Size Chart, AWG Wire Gauge, American Wire Gauge, AWG Cable, Wire Gauge Sizes, and AWG Table all relate to the same thing.
Note that the wire gauge table concerns the physical size of the wire and does not address a cable;
As a cable would be insulated wires with attached connectors or a number of wires within an insulating jacket.
Related technical data on Chassis Cable Design and Considerations
B&S Note: The term 'Brown and Sharpe' is out dated in regards to the American Wire Gauge.
By the early 1900's the Brown and Sharpe table became known as the American Wire Gauge.
I'm not really sure why it is even being referenced any longer.
Brown and Sharpe was a company that produced wire.
Magnet wire and normal copper wire will have the same wire gauge, as the enameled coating over bare wire does not add much thickness.
Wire Rope is not referenced here because wire rope is stranded wire, while the AWG table covers solid wire.