7/25/2019 Sample Cable Calculation

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4mm - 3c - 31mCopper:Cable:90C:XLPE:SWA:BS5467:600/1000v

C Clipped direct

CPC(1) = 6.43mm

CPC(2) = 4mm

RCBO 30mA

32ARCBO 30mA 32A

Max Zs = 1,666.000

= 1.78kA

400.00V - 50Hz

0.1300 0.95pfTN-STPN

26.00A ()Radial circuit

Fixed equipment

393.2 / 227.0V

Cable DataCopper:Cable:90C:XLPE:SWA:BS5467:600/1000v:Table 4E4

Cable Rating (tabulated) Table 4E4A Col-3 42A

Cable Rating (effective) 42A PASS

mV/A/mtr (tabulated) Table 4E4B Col-4 10mV/A/m (r)

mV/A/mtr (temperature corrected) operating 52.99C 8.844mV/A/m (r)

Voltage drop permitted (per phase) 4.00% (9.24V)

Voltage drop Calculated (per phase) 1.69% PASSCircuit voltage drop = 3.91V

Correction FactorsAmbient temperature () 30C = 1.000 Table 4B1

Grouping () 1 ccts = 1.000 Table 4C1

Thermal Insulation () 0mm = 1 Table 52.2

Circuit Protective conductors (cpc)Minimum CPC size ( S = It/k ) 1.30mm k = 143 0.100 sec I = 589.21 A

Cable sheath (copper equivalent) 6.43mm 6.43mm

Internal core 4mm 4mm PASSCPC It/k)

Protective Device DetailsRCBO 30mA 32A

Selected for Short-circuit protection only

Rating () 32 PASS32 26

Breaking capacity () 6kA 6 1.78 PASS

Operating current () 0.03A

Calculated disconnection time 0.100 sec PASS

Maximum permitted disconnection time 0.2 sec Table 41.1

Impedance of device (Z) 1,666.000 PASS1,666.000 0.3920 Z Zs

Earth Fault DataEarth fault loop impedance (Ze) 0.1300

Circuit R1 value 0.1618

Circuit R2 value 0.1002

Circuit R1+R2 value 0.2620

Earth loop impedance (Zs=Ze+R1+R2) 0.3920 PASS1,666.00 0.3920 Z Zs

Earth fault current (=/Zs) 589.21A = 230.95V Zs = 0.3920

Short Circuit DataProspective short curcuit current 1.78 kA

Short circuit withstand time (t = kS/I) 0.942 sec k = 143 S = 4mm I = 589.21 A

Castline Systems - CableCalc BS7671 (17th Edition) Version 5.0.1.26

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