Current-Carrying (Fusing) Capacity of Wire
March 1935 Radio-Craft

March 1935 Radio-Craft [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

Radio-Craft magazine used to run a feature where readers would write in with questions, and someone on the staff would respond. This March 1935 issue's query requested a table containing maximum current carrying (fusing) capacities for various wire gauge sizes. Values of fusing current were provided for 10 through 40 GA, for copper, German silver, and iron. The "B. & S. Gauge" wire size scale refers to Brown & Sharpe, which now goes by the designation of American Wire Gauge (AWG).

Current-Carrying Capacity of Wire

(313) Mr. L. L. Sander, Los Angeles, Calif. (Q.) I should be glad if you would tell me where a chart showing current-carrying capacity of wires of various gauges can be obtained.

(A.) Since a wire will pass current until it fuses, we print herewith an interesting chart (courtesy of General Electric Supply Company) showing current necessary to fuse wires of different gauges and materials. Note that a No. 40 copper wire will actually take over 1.5 amps. without fusing!

Current Required to Fuse Wires, Copper, German Silver, and Iron

Posted November 3, 2023
(updated from original post on 10/10/2016)