Electrical calculators
All calculators
- Cable sizeCurrent rating, voltage drop, earthAS/NZS 3008
- Maximum demandDiversity by load groupAS/NZS 3000
- Arc flashIncident energy and boundaryIEEE 1584
- Voltage riseInverter export on consumer mainsAS/NZS 3008
- Voltage dropDrop, size or run lengthAS/NZS 3008
- IDMT trip timeIEC and IEEE curvesIEC 60255 / IEEE C37.112
- Motor currentFull-load amps from kW or hpIEC / NEMA
- Motor speedSynchronous RPMAC machines
- Motor torqueRated torque from kW and RPMAC machines
- Transformer currentFLC and turns ratioIEC 60076
- Transformer fault currentBolted faults from %ZIEC 60909
- Generator load currentFull-load ampsIEC 60034
- Generator fault currentFrom %XdIEC 60909
- Battery sizeAh from load, hours and voltageDC systems
- Full-load currentAny load, any supplyGeneral
- Three-phase powerP, Q and S from V, I, pfGeneral
DC systems
Battery size
Voltage is always editable (12 / 24 / 48 / 110 V and so on). When load is in watts, Ah uses voltage. When load is in amps, Ah is from current and hours; voltage still records the system.
General
Full-load current
General
Three-phase power
IEC / NEMA
Motor current
AC machines
Motor speed
AC machines
Motor torque
IEC 60076
Transformer current
IEC 60909
Transformer fault current
IEC 60034
Generator load current
IEC 60909
Generator fault current
AS/NZS 3008
Voltage drop
ΔV = I · L · k · Zc / 1000, with k = 2 (1-ph / DC) or √3 (3-ph). Worst-case Zc = √(R² + X²); or R cos φ + X sin φ. AS/NZS 3000 allows 5% from the point of supply, or 7% from a transformer LV terminal. R from Table 35 / IEC 60228 at the conductor temperature.
AS/NZS 3008 · AS/NZS 4777.1
Voltage rise
AS/NZS 4777.1 typically limits rise at the inverter terminals to 2%. Segment rise uses worst-case |Z| at 75 °C Cu multi-core (Table 35 / Table 30 family).
AS/NZS 3008
Cable size
CCC from AS/NZS 3008-style Table 27 (air / ground) with Table 22 grouping and temperature factors. Voltage drop uses Table 35-family R and Table 30-family X. Earth from AS/NZS 3000 Table 5.1. Typical published values — confirm in the Standard for the final design.
AS/NZS 3000 Appendix C
Maximum demand
Diversity follows AS/NZS 3000:2018 Appendix C. Lighting and 10 A sockets on a house use point allowances, not connected-load sums. A double GPO counts as two 10 A socket points.
IEC 60255 / IEEE C37.112
IDMT trip time
IEEE 1584-2002
Arc flash
IEEE 1584-2002 empirical model (208 V–15 kV). Ralph Lee is used above 15 kV or when selected. Typical 2018 gaps and working distances are filled when you change equipment type. Not a substitute for a full IEEE 1584 study.