7. ELECTRICAL CHARACTERISTICS - Anixter

1 7. Resistance of Plated Copper and AC Resistance of Copper and AC Resistance of Aluminum and Impedance at 60 Resistance Ratio at 60 Correction Factors for Conductor Short Circuit Shield Short Circuit and Ampacity at 400 and 800 Ratings for Electronic of Power Impulse Level (BIL) Ratings1097. ELECTRICAL CHARACTERISTICS || 91 92|For a wire or cable to perform its intended function reliably, safely and efficiently, the wire or cable must be selected so that its many ELECTRICAL , physical,chemical and thermal properties match those of the following sections provide information on some of the most frequently requested ELECTRICAL DC RESISTANCE OF PLATED COPPER CONDUCTORST able DC Resistance of Plated Copper ConductorsWire SizeNo.

2 Of Wires/SizeStrandNominal AreaNominal DC Resistance ohms /1,000 ft. at 20 C (68 F)(AWG/kcmil)(AWG or in.)Class(cmils)Silver PlatedNickel PlatedTin Plated7771,952/24 AAR788,728 ,711 ,862/24I752,267 ,448/30K744,800 ,988 ,729/24I698,533 ,916/30K691,600 ,684 ,596/24I644,800 ,517/30K651,700 ,647/24 AAR665,404 ,406 ,470/24I593,895 ,985/30K598,500 ,152 ,372/24I554,302 ,453/30K545,300 ,332/24 AAR538,141 ,436 ,125/24I494,912 ,054/30K505,400 ,019 ,127/24I455,319 ,522/30K452,200 ,110/24 AAR448,451 ,826 ,930 ,990/30K399,000 ,709 ,269 on next page >>|7. ELECTRICAL Characteristics7. ELECTRICAL CHARACTERISTICS || 93 Table DC Resistance of Plated Copper Conductors (Continued)Wire SizeNo.

3 Of Wires/SizeStrandNominal AreaNominal DC Resistance ohms /1,000 ft. at 20 C (68 F)(AWG/kcmil)(AWG or in.)Class(cmils)Silver PlatedNickel PlatedTin Plated350882/24I356,337 ,458/30K345,800 ,916 ,861 ,947 ,989/30K298,900 ,990 ,068 ,354 ,499/30K249,900 ,109/30K210, , ,665/30K166, , ,330/30K133, , ,045/30K104, , , , , , , , , , , , , , , , , , , , , , , on next page >>|7. ELECTRICAL Characteristics94|Table DC Resistance of Plated Copper Conductors (Continued)Wire SizeNo. of Wires/SizeStrandNominal AreaNominal DC Resistance ohms /1,000 ft. at 20 C (68 F)(AWG/kcmil)(AWG or in.)Class(cmils)Silver PlatedNickel PlatedTin Plated1419/27C3, , , , , , , , , , , , , , ,000 , : AAR American Association of RailroadsStrand Classes B, C, D, H, I and K per ASTM7.

4 ELECTRICAL CHARACTERISTICS || DC AND AC RESISTANCE OF COPPER CONDUCTORST able DC and AC Resistance of Copper Conductors, Nominal Ohms Per 1,000 C60 C75 C90 CConductorConductorConductorConductorSiz eTemperatureTemperatureTemperatureTemper atureDCDC60 Hz ACDC60 Hz ACDC60 Hz AC*Single Multi-*Single Multi-*Single Multi-(AWG/kcmil) , , 1, 1, on next page >>|7. ELECTRICAL Characteristics96|Table DC and AC Resistance of Class B Copper Conductors, ohms per 1,000 ft. (Continued)20 C60 C75 C90 CConductorConductorConductorConductorSiz eTemperatureTemperatureTemperatureTemper atureDCDC60 Hz ACDC60 Hz ACDC60 Hz AC*Single Multi-*Single Multi-*Single Multi-(AWG/kcmil) , , , , , , 3, 5, Note: 40 AWG through 26 AWG values are for solid conductors, all others are for ASTM Class B stranded conductors.

5 *One single conductor in air, buried or in nonmetallic conduit. Multiconductor cable or two or three single conductors in one metallic Temperature Correction Factors for Copper DC ResistanceTemperature ( C) Multiplying Factors for Correction To:20 C25 :The DC resistance of a 500 kcmil copper conductor at 60 C is ohms per 1,000 ft. The resistance at 25 C would be 3 ohms per 1,000 ELECTRICAL CHARACTERISTICS || DC AND AC RESISTANCE OF ALUMINUM CONDUCTORST able DC and AC Resistance of Class B Aluminum Conductors, ohms Per 1,000 C 75 C90 CSizeConductor TemperatureConductor Temperature Conductor TemperatureDC60 Hz ACDC60 Hz ACDC60 Hz AC*Single Multi-*Single Multi-*Single Multi-(AWG/kcmil) , , , , , *One single conductor in air, buried or in nonmetallic conduit.

6 Multiconductor cable or two or three single conductors in one metallic conduit.|7. ELECTRICAL Characteristics98|Table Temperature Correction Factors for Aluminum DC ResistanceTemperature ( C) Multiplying Factors for Correction To:20 C25 :The DC resistance of a 500 kcm aluminum conductor at 60 C is ohms per 1,000 ft. The resistance at 25 C would be 3 ohms per 1,000 REACTANCE AND IMPEDANCE AT 60 HzTable Reactance and Impedance at 60 Hz for Single Copper Conductor Cables Installed in Air, Buried or in Separate Nonmetallic ConduitsConductor SizeApproximate ohms per 1,000 ft. per Conductor at 25 C (77 F)Distance Between Centers of Conductors2 in.

7 (AWG/kcmil) on next page >>7. ELECTRICAL CHARACTERISTICS || 99 Table Reactance and Impedance at 60 Hz for Single Copper Conductor Cables Installed in Air, Buried or in Separate Nonmetallic Conduits (Continued)Conductor SizeApproximate ohms per 1,000 ft. per Conductor at 25 C (77 F)Distance Between Centers of Conductors2 in.(AWG/kcmil) , , , , , equations that can be used to calculate inductive reactance for other conductor spacings, see Section |7. ELECTRICAL Characteristics100| AC/DC RESISTANCE RATIO AT 60 HzTable AC/DC Resistance Ratio at 60 HzTo determine effective 60 Hz AC resistance, multiply DC resistance values corrected for proper temperature by the AC/DC resistance ratio given Copper Conductor Cable or Two Conductor SizeSingle Copper Conductors in Air, or Three Single Conductor Cables in(AWG/kcmils)or in Individual Nonmetallic ConduitsSame Metallic ConduitUp to and 1, 1, 1, 1, 2, Source.

8 Underground Systems Reference Book, Edison Electric Institute, single conductor column in the table above covers single conductor nonshielded cable having spacing of six inches or more including all conditions of use except when two or more cables are pulled into the same metallic or nonmetallic multiple conductor column in the table above covers the following conditions:(a) Single conductor cable; two or three cables in the same metallic conduit.(b) Single conductor shielded cable; two or three cables in the same metallic or nonmetallic duct or conduit, but only with conductor sizes up to 250 larger conductor sizes the short-circuited sheath losses increase rapidly and the table above does not apply.

9 (c) Three conductor nonshielded cable; one cable in metal conduit.(d) Three conductor shielded cable; all conditions of use in air, in ducts and in table represents maximum AC losses for the conditions ELECTRICAL CHARACTERISTICS || TEMPERATURE CORRECTION FACTORS FOR RESISTANCET able Temperature Correction Factors for the Resistance of Copper ConductorsTemp CMultiplying DC resistance of copper wire increases with increasing temperature in accordance with the formula:Rt5Ro[1 1a (T2To)]Where:Rt5 Resistance at temperature TRo5 Resistance at temperature Toa5 Temperature coefficient of resistance at To[At 20 C (68 F) the temperature coefficient of copper is per degree Celsius|7.]

10 ELECTRICAL Characteristics102| VOLTAGE DROPThe values in Tables copper conductors and aluminum conductors are calculated at 60 C, the estimated average temperature that may be anticipated in service. They may be used without significant error for conductor temperatures up to and including 75 C. For 90 C multiply by for copper and by for aluminum. To obtain values for other circuits, multiply by for single-phase line-to-line and by for single- or drop =Voltage drop in percent =Table Phase-to-Phase Voltage Drop Per Amp Per 100 ft. of Circuit for a Three-Phase, 60 Hz System Operating at 60 C with Copper ConductorsSizeIn Non-Magnetic ConduitIn Magnetic ConduitPercent Power FactorPercent Power Factor(AWG/kcmil) , drop in V 3 100 Circuit voltage in VTable value 3 Current in amps 3 Length of circuit in feet1007.