Wire Gauges and Max Current

Thread Starter

SteveO

Joined May 15, 2008
33
I have a project in which a number of different power supplies need to be re-wired.

Could someone send me in the direction of a chart which will list the maximum current ratings for a given AWG, corresponding to safety regulations. I have found a few but they all seem to differ from one another. I need everything from down to 2 A to just over 100 A.

Thanks.

Regards,
Steven
 

Thread Starter

SteveO

Joined May 15, 2008
33
Thank you for your quick and accurate response.

edit: Is I @ 3A /mm^2 to insure safety precautions? Thanks.

Regards,
Steven
 

Papabravo

Joined Feb 24, 2006
21,225
AWG with metric dimensions -- how cute. Kinda buries the use of circular mils on which the guage was based. One should never start vast projects with half vast ideas.
 

thingmaker3

Joined May 16, 2005
5,083
Thank you for your quick and accurate response.

edit: Is I @ 3A /mm^2 to insure safety precautions? Thanks.

Regards,
Steven
It's not quite that simple. As the wire becomes larger, it is rated for fewer amps per unit area. This is due to smaller wires having more surface area per unit volume, and therefore being able to dissipate more heat. Similar current densities for larger wire would result in unacceptable temperature increases.

Also, ampacity for a given wire size will depend on application. Ratings for free air wiring are higher than for enclosed wiring. Ratings for chassis wiring (which is necessarily short by comparison) are higher still. Ratings for coils are much lower.
 
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