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1. These resistance values are valid only for the parameters as given. Using conductors having coated strands, different stranding type, and, especially, other temperatures changes the resistance. 2. Equation for temperature change: R 2 = R 1 [1 + α (T 2 − 75)] where α cu = 0.00323, α AL = 0.00330 at 75°C. 3.
25 lis 2010 · Electrical resistance in plain copper or aluminum wires. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! Electrical resistance in single core conductors:
Information in this chart is based on initial temperature of 65°C, final temperature of 200°C, 5 mil copper tape with 12.5 percent overlap. * These derating factors do not apply to cables with metallic sheath or armor, nor to cables installed in conduit or adjacent to steel structures.
Maximum Current: These ampacities are based on a very moderate rating of 700 circular mils per amp (cma). Determining a more accurate current rating depends on a variety of factors including the surrounding materials, permissible temperature rise, and specific usage of the wire.
Logical AWG numbers are based on continuing the series in a logarithmic relationship to the cross sectional area of the wire.
Direct-Current Resistance at 750C (167 OF) Copper Size (AWG kcmil) 18 14 14 10 6 4 2 1/0 2/0 3/0 4/0 250 300 350 400 500 600 750 soo 900 1 ooo 1250 1500 1750 Area Circular Stranding Diameter Overall Aluminum Area Uncoated Coated mm 0.39 0.62 0.78 0.98 123 1.56 1.96 2.20 247 1.69 I .89 2.13 2.39 2.68 2.09 2.29 247 2.64 2.95 2.52 2.72 2.82 2.91 3.09
TABLE 1 - 3 Resistance in Ohms per 1000 feet per Conductor at 20°C and 25°C of solid wire and Class B Concentric Strands Copper and Aluminum Conductors 3 TABLE 1 - 4 Copper and Aluminum Resistance-Temperature Correction Factors 4 TABLE 1 - 5 AC/DC Resistance Ratios - for Copper and Aluminum Conductors, 60 Hertz (65°C) 5
