EDP-3 - Cooper Bussmann

Protecting System ComponentsA. Wire and CableAllowable Short-Circuit Currents for Insulated Aluminum Conductors*1008060504030SHORT CIRCUIT CURRENT - THOUSANDS OF AMPERES20108654321.8.6.5.4.3.21 CYCLE – 0.0167 SECOND2 CYCLES – 0.0333 SECOND4 CYCLES – 0.0667 SECOND8 CYCLES – 0.1333 SECOND16 CYCLES – 0.2667 SECOND30 CYCLES – 0.5000 SECOND60 CYCLES – 1.0000 SECOND100 CYCLES – 1.6667 SECONDCONDUCTOR: ALUMINUMINSULATION:THERMOPLASTICCURVES BASED ON FORMULA:⎡ I ⎤ 2 t = .0125 log ⎡ T 2 + 228 ⎤⎣A ⎦⎣T 1 + 228 ⎦WHERE:I = SHORT-CIRCUIT CURRENT - AMPERESA = CONDUCTOR AREA - CIRCULAR MILSt = TIME OF SHORT-CIRCUIT - SECONDST 1 = MAXIMUM OPERATING TEMPERATURE -75°CT 2 = MAXIMUM SHORT-CIRCUIT TEMPERATURE -150°C.110 8 6 4 2 1 1/0 2/0 3/0 4/0 AWGCONDUCTOR SIZE 250 MCM 500 1000Figure 10. Short-Circuit Current Withstand Chart for Aluminum Cable with Thermoplastic Insulation*Copyright 1969 (reaffirmed March, 1992) by the Insulated Cable Engineers Association (ICEA). Permission has been given by ICEA to reprint this chart.12