Cable Calculator

AS/NZS 3008.1.1:2017 & AS/NZS 3000:2018 (Educational Mode)

Maximum Demand & Phase Balancing

Filter:

Description	Group	Value	Unit	Phase

Phase Balance Analysis {{ inputs.selectedGroup }} Only

{{ phaseTotals.L1.toFixed(1) }}A

{{ phaseTotals.L2.toFixed(1) }}A

{{ phaseTotals.L3.toFixed(1) }}A

{{ group }}: {{ amps.toFixed(1) }} A

{{ inputs.selectedGroup }}: {{ (groupTotals[inputs.selectedGroup] || 0).toFixed(1) }} A

Calculated Demand: {{ maxDemand.toFixed(1) }} A

Calculation Mode

Auto-Size Cable (Find Minimum)

Manual Goal:

Parameters

Selected Cable

System Voltage

Load (A) Auto

Length (m) Auto

Max Voltage Drop (%)

Design & Derating Factors

Ambient Temperature (°C)

Standard ambient is 40°C. Affects $C_t$ factor (AS3008 T27).

Number of Grouped Circuits

1 = No grouping derating. Affects $C_g$ factor (AS3008 T22).

Earth Sizing (Zs)

Manual Earth Conductor Size

Select Earth Size

Earth conductor size is calculated automatically based on the final active cable size (AS/NZS 3000:2018 Table 5.1).

Spec & Protection

Cable Insulation

Installation

Protective Device

Auto-set

Auto-set to {{ inputs.deviceRating }}A (Next Standard ≥ Load)

{{ inputs.isAuto ? 'Recommended Cable Size' : 'Manual Selection Result' }}

{{ results.displayMainValue }} {{ results.displayMainUnit }} {{ getCableDescription }} {{ results.overallStatus === 'Pass' ? 'OK' : 'FAIL' }}

Limiting Factor: {{ results.limitingFactor }} {{ getCableDescription }}

Sizing Analysis

1. Minimum for Current ({{ results.calcLoad }}A): {{ results.analysis.cccSize }} mm²

2. Minimum for Voltage Drop ({{ inputs.maxVd }}%): {{ results.analysis.vdSize }} mm² (Upsized)

3. Minimum for EFLI (Zs): {{ results.analysis.efliSize }} mm² (Upsized)

Recommended size is the maximum of these three values.

Current Capacity PASS FAIL

Design Current (Ib) {{ results.calcLoad.toFixed(1) }} A

Cable Rating (Iz) {{ results.cableRating.toFixed(1) }} A

Iz must be ≥ Ib. Table {{ results.tableRef }} Col {{ results.colRef }}.

Voltage Drop PASS FAIL

Limit ({{ inputs.maxVd }}%) {{ results.maxVdVolts.toFixed(2) }} V

Calculated Drop {{ results.calcVdVolts.toFixed(2) }} V

Calculated % {{ results.calcVdPercent.toFixed(2) }}%

Earth Fault Loop Impedance PASS FAIL

Device (Ia) {{ results.tripCurrent }} A

Max Zs (Uo/Ia) {{ results.maxZsCold.toFixed(3) }} Ω

Earth Conductor {{ results.earthSize }} mm²

Cable Z (Zint) {{ results.cableZ.toFixed(3) }} Ω

External Z (Zext) {{ results.appliedZext.toFixed(3) }} Ω

Total Loop Zs {{ results.totalZs.toFixed(3) }} Ω

Formulas & Reference

1. Current Carrying Capacity (CCC) (AS/NZS 3008 Clause 3.4)

// Condition: Ib ≤ Iz(final)

// Formula: Iz(final) = Iz(table) x Cg x Ct

// Iz (table) Ref: AS/NZS 3008 Table {{ results.tableRef }} Col {{ results.colRef }}

// Iz (Table) = {{ results.izTable }} A (for {{ results.selectedSize }}mm²)

// Cg (Grouping Factor, Table 22/24 est.) = {{ results.cgFactor.toFixed(2) }}

// Ct (Temperature Factor, Table 27 est.) = {{ results.ctFactor.toFixed(3) }}

Iz (final) = {{ results.izTable }} * {{ results.cgFactor.toFixed(2) }} * {{ results.ctFactor.toFixed(3) }} = {{ results.cableRating.toFixed(1) }} A

Ib (Design Load) = {{ results.calcLoad.toFixed(1) }} A

2. Voltage Drop Calculation (AS/NZS 3008 Clause 4.2)

// Formula: Vd = (L * I * Vc) / 1000

// Ref: AS/NZS 3008 Table {{ results.vdTableRef }} Column {{ results.vdColRef }} (Multicore Copper)

Manual Vc Override (mV/A.m):

Length (L) = {{ results.calcLength }} m

Current (I) = {{ results.calcLoad }} A

Vc Base (3-Phase) = {{ results.baseVcFactor.toFixed(4) }} mV/A.m

Adjusted Vc (1Ph) = {{ results.baseVcFactor.toFixed(4) }} * 1.155 = {{ results.vcFactor.toFixed(3) }} mV/A.m

Vd = ({{ results.calcLength }} * {{ results.calcLoad }} * {{ results.vcFactor.toFixed(3) }}) / 1000 = {{ results.calcVdVolts.toFixed(2) }} V

Percentage = ({{ results.calcVdVolts.toFixed(2) }} / {{ inputs.phase == 1 ? 230 : 400 }}) * 100 = {{ results.calcVdPercent.toFixed(2) }}%

3. Earth Fault Loop Impedance (Zint) (AS/NZS 3000 Appendix B)

// Formula: Z_cable = L/1000 * √((Rph + Re)² + (Xph + Xe)²)

// Reference: AS/NZS 3008.1.1 Table 35 (R) & Table 30/42 (X) (Multicore Copper)

// Resistance values at operating temperature (Conservative)

R_ph ({{ results.selectedSize }}mm²) = {{ results.debug_Rph }} Ω/km

R_e ({{ results.earthSize }}mm²) = {{ results.debug_Re }} Ω/km

X_ph (Reactance) = {{ results.debug_Xph }} Ω/km

X_e (Reactance) = {{ results.debug_Xe }} Ω/km

R_loop = ({{ results.debug_Rph }} + {{ results.debug_Re }}) * ({{ results.calcLength }}/1000) = {{ results.debug_Rloop }} Ω

X_loop = ({{ results.debug_Xph }} + {{ results.debug_Xe }}) * ({{ results.calcLength }}/1000) = {{ results.debug_Xloop }} Ω

Z_cable = √({{ results.debug_Rloop }}² + {{ results.debug_Xloop }}²) = {{ results.cableZ.toFixed(4) }} Ω

4. Total Zs & Compliance

Ia (Trip Current) = {{ results.tripCurrent }} A ({{ formatDevice(inputs.deviceType) }} {{ inputs.deviceRating }}A)

Zs Max (Uo/Ia) = 230 / {{ results.tripCurrent }} = {{ results.maxZsCold.toFixed(3) }} Ω

Z_ext (External) = {{ results.appliedZext.toFixed(3) }} Ω

Total Zs = {{ results.appliedZext.toFixed(3) }} + {{ results.cableZ.toFixed(4) }} = {{ results.totalZs.toFixed(3) }} Ω

Result: {{ results.totalZs.toFixed(3) }} Ω {{ results.totalZs <= results.maxZs ? '<=' : '>' }} {{ results.maxZs.toFixed(3) }} Ω ({{ results.limitRule }})