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- 4 Nov 2026 · 4 min read1000 kVA transformer amps at 11 kV
Full load current for a 1000 kVA 11 kV to 400 V transformer, with the primary current, the secondary current and the fault current at 5 % impedance.Transformer1 reference - 3 Nov 2026 · 3 min readConduit size for 35 mm cable in a submain
Four 35 mm² singles in a 50 mm conduit fill 19.48 % of the internal area, and the AmpSize engine still recommends a 40 mm conduit for this submain.Conduit fill2 references - 3 Nov 2026 · 3 min readElectricity Safety Regulations: reg 57 and 59
What reg 57 and reg 59 of the Electricity (Safety) Regulations 2010 govern, and a house that reaches 100.26 A and crosses the reg 59(1) threshold of 80 A.Maximum demand5 references - 2 Nov 2026 · 5 min readBuilder's pole: supply, RCDs and cord lengths
A builder's pole for a house build, worked to AS/NZS 3012:2019. The supply it may take, the 30 mA RCDs, the Table 1 cord lengths and the test intervals.Site cord length8 references - 2 Nov 2026 · 4 min readCar-park floodlight: obtrusive light at a boundary
Two 10 000 lm floodlights 10 m from a neighbour's window in zone A2, checked against AS/NZS 4282 for lux at the window, candela and the upward light ratio.Obtrusive light5 references - 1 Nov 2026 · 3 min readHomeowner shed supply voltage drop over 60 m
A 20 A single‑phase supply running 60 m to a shed on 6 mm² copper, with the drop, the percentage and the maximum length the AmpSize voltage drop engine returns.Voltage drop4 references - 31 Oct 2026 · 3 min readCommercial kitchen kW to amps full load current
Turning a 30 kW commercial kitchen nameplate load into 45.58 A at 400 V three phase, with the power factor step that a plain kW to amps sum leaves out.Full load current2 references - 31 Oct 2026 · 3 min readGenerator fault current calculation at 400 V
A 500 kVA 400 V standby set at 12 % subtransient reactance gives 721.69 A full load and 6014.07 A fault current, with the decay the figure leaves out.Generator current2 references - 30 Oct 2026 · 3 min readIEEE 1584-2002: arc flash model and limits
What the IEEE 1584-2002 empirical model governs, where it stops applying, and a 400 V switchboard study that lands on 7.54 cal/cm² at 455 mm.Arc flash5 references - 29 Oct 2026 · 5 min readArc flash at a 48 V home battery
Class a 48 V lithium home battery with 6 kA at its terminals by AS/NZS 5139, find its arc flash energy and PPE level, then bring it down with fuses.Battery arc flash and class6 references - 29 Oct 2026 · 3 min readDairy shed IDMT relay setting and grading
Three IDMT relays at a 3000 A fault, two grading margins and one curve inversion between the shed main and the farm incomer, read off the AmpSize relay engine.IDMT protection3 references - 28 Oct 2026 · 3 min readDairy shed motor current: 15 kW at 400 V
Full load current, shaft speed, torque and DOL starting current for a 15 kW 400 V dairy shed vacuum pump motor, worked through the AmpSize motor engine.Motor2 references - 28 Oct 2026 · 5 min readOhm's law on a 3 kW water heater element
Work the current and working resistance of a 3 kW, 230 V water heater element with Ohm's law, why a cold meter reading is lower, then a 9 kW three‑phase bank.Ohm's law1 reference - 28 Oct 2026 · 3 min readLighting circuit loop impedance, B curve 10 A
A 60 m shop lighting circuit on 1.5 mm² cable with a B curve 10 A device, showing Zs, the maximum Zs, the fault current and the longest run that passes.Loop impedance4 references - 27 Oct 2026 · 5 min readRCD tripping with no fault: add up the leakage
An RCD on a home office and kitchen trips with no fault found. Add up the standing leakage, check it against a third of 30 mA, and split it over two RCDs.RCD leakage budget2 references - 27 Oct 2026 · 3 min readVoltage drop single phase vs three phase
The same 6 mm² cable at 32 A over 50 m, worked on a three phase supply and on a single phase supply, with both drops, both percents and both run limits.Voltage drop3 references - 26 Oct 2026 · 3 min readIEC 60255-151: IDMT curve constants
What IEC 60255-151 governs, which curve sets the IDMT tool carries, and a worked grading pair on standard inverse that clears in 0.21 s and 0.74 s.IDMT protection2 references - 26 Oct 2026 · 5 min readWhat size generator for a dairy shed
Size a standby set for a dairy shed from its load list. The vacuum pump's start sets the size, then staggered steps, a drive and a soft starter shrink it.Generator sizing1 reference - 25 Oct 2026 · 3 min readBattery backup for a PLC panel at 24 V DC
Sizing a 24 V DC backup bank for an 80 W PLC panel over one day of autonomy, with the daily energy, the daily charge and the bank capacity the tool returns.Battery1 reference - 25 Oct 2026 · 3 min readFixed heating maximum demand with Table C1
Adding 7.5 kW of fixed heating to a house under Table C1 group D, the demand each group contributes, and the 80 A line that reg 59 draws.Maximum demand3 references - 24 Oct 2026 · 3 min readArc flash boundary at a motor control centre
Arcing current, incident energy and arc flash boundary for a 400 V MCC at 25 kA with a 0.1 s clearing time, and why the equipment type moves the result.Arc flash3 references - 23 Oct 2026 · 5 min readCable tray fill for a plant room: a second tier
Lay ten multicore cables on a 300 mm perforated tray in one layer, see when it takes a second tier, and carry the grouping factor into the cable size.Cable tray fill2 references - 23 Oct 2026 · 3 min readMotor starting current for a 55 kW DOL start
Full load current, DOL starting current, shaft speed and torque for a 55 kW four pole motor at 400 V, and what a soft starter or a VSD changes.Motor2 references - 22 Oct 2026 · 2 min readA circuit chart for a house board with solar
The circuit chart and labels for a six-circuit house board with a solar inverter: ways, devices, RCDs, MAIN SWITCH, MAIN SWITCH SOLAR and a shared neutral.Circuit chart4 references - 22 Oct 2026 · 4 min readSwitchboard fault rating at 25 kA for 1 s
A 1 second withstand check at 25 kA on 185 mm² copper XLPE, returning a 174.83 mm² minimum size and a 26.46 kA withstand, with a thin margin explained.Fault rating4 references - 21 Oct 2026 · 3 min readA test sheet for a house board
A test sheet for a six-circuit New Zealand house board, with the tests in the AS/NZS 3017 order and the limit for each reading, then the Australian sheet.Test schedule5 references - 20 Oct 2026 · 3 min readHot water cylinder cable size for a 3 kW element
A 16 A hot water circuit run 20 metres through wall insulation at 35 degrees, sized to 2.5 mm² with 17.86 A of derated capacity and 2.27 % voltage drop.Cable size6 references - 20 Oct 2026 · 2 min readIP ratings for an outdoor point and a hosed shed
Which IP code an outdoor power point, a milking shed light and a hosed switchboard need, and why an IP67 light can fail where IP65 passes.IP rating4 references - 19 Oct 2026 · 3 min readReading the wiring in an older house
A 1970s New Zealand house with yellow actives, a green earth and a black neutral. What each colour can be, what may stay, and how to sleeve new terminations.Conductor colours4 references - 19 Oct 2026 · 4 min readConsumer mains fault withstand for 16 mm² copper
A domestic 6 kA fault cleared in 10 milliseconds against 16 mm² copper PVC mains, giving a 5.41 mm² minimum size and a 17.76 kA adiabatic withstand.Fault rating3 references - 18 Oct 2026 · 3 min readGenerator full load current: 200 kVA to amps
A 200 kVA 400 V standby set converted to 288.68 A of full load current, 160 kW of real power and 2,405.63 A of initial fault current from 12 % reactance.Generator current1 reference - 17 Oct 2026 · 3 min readOffice maximum demand per phase with Table C2
An office fitout load schedule assessed against AS/NZS 3000 Table C2, group by group, landing on 413.7 A across three phases and 137.9 A per phase.Maximum demand2 references - 16 Oct 2026 · 3 min readDC isolator rating for a 10 kW solar array
Rate the d.c. isolator and size the frame earth for a four-string domestic array. Check one data sheet that passes and one that fails per pole.PV array isolator and earthing5 references - 16 Oct 2026 · 3 min readSolar string sizing for a 600 V inverter
How many 49.5 V modules fit a string on a 600 V inverter at −5 °C? Work cold Voc, hot Vmp, the string current, fuses and the d.c. isolator by AS/NZS 5033.PV string sizing6 references - 15 Oct 2026 · 1 min readHow far can 1.5 mm² run on a 10 A circuit?
1.5 mm² copper on a 10 A curve C circuit can run 34.85 m before it reaches the 5 % voltage drop limit. The fault loop alone would allow 82 m.Maximum circuit length2 references - 15 Oct 2026 · 1 min readHow far can 4 mm² run on a 25 A circuit?
4 mm² copper on a 25 A curve C circuit can run 41 m at full load before it reaches the 5 % voltage drop limit. At 20 A of load it can run 51.25 m.Maximum circuit length2 references - 15 Oct 2026 · 1 min readHow many amps can 1.5 mm² cable carry?
1.5 mm² copper multicore PVC cable carries 16 A enclosed in air at 30 °C in NZ, so it takes a 16 A breaker. Clipped direct, it carries 17 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many amps can 10 mm² cable carry?
10 mm² copper multicore PVC cable carries 50 A enclosed in air at 30 °C in NZ, so a 50 A breaker protects it. Clipped direct, it carries 58 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many amps can 16 mm² cable carry?
16 mm² copper multicore PVC cable carries 66 A enclosed in air at 30 °C in NZ, so it takes a 63 A breaker. Grouped with two circuits, it carries 46.2 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many amps can 2.5 mm² cable carry?
2.5 mm² copper multicore PVC cable carries 23 A enclosed in air at 30 °C in NZ, so a 20 A breaker protects it. Grouped with two circuits, it carries 16.1 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many amps can 2.5 mm² carry in Australia?
2.5 mm² copper multicore PVC cable carries 20 A enclosed in air at 40 °C on AS/NZS 3008.1.1:2025, exactly a 20 A breaker. Clipped direct, it carries 22 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many amps can 6 mm² cable carry?
6 mm² copper multicore PVC cable carries 38 A enclosed in air at 30 °C in NZ, so it takes a 32 A breaker. At 40 °C it carries 33.44 A.Circuit check3 references - 15 Oct 2026 · 1 min readHow many 2.5 mm² cables fit in 20 mm conduit?
Six single‑core 2.5 mm² cables fit in 20 mm conduit at 34.56 % fill, inside the 40 % limit of AS/NZS 3000 Appendix C. A seventh takes it to 40.32 %.Conduit fill1 reference - 15 Oct 2026 · 1 min readHow many lights on a 10 A circuit?
In a home, AS/NZS 3000 Table C9 fills a 10 A circuit at 20 lighting points. A 21st point takes the sum over the circuit-breaker rating.Circuit loading1 reference - 15 Oct 2026 · 1 min readHow many power points on a 20 A circuit?
In a home, AS/NZS 3000 Table C9 fills a 20 A circuit at 20 single 10 A socket‑outlets. A non‑domestic installation counts each one at twice that.Circuit loading1 reference - 15 Oct 2026 · 1 min readMaximum Zs for a 16 A curve C breaker
AS/NZS 3000 Table 8.1 allows a maximum Zs of 1.92 Ω for a 16 A curve C breaker at 230 V. A 30 m run of 2.5 mm² cable reads 0.89 Ω.Loop impedance2 references - 15 Oct 2026 · 1 min readMinimum cable size for a lighting circuit
AS/NZS 3000 Table 3.3 sets a minimum of 1 mm² copper for circuits other than socket‑outlets, lighting included. The load and the run often need more.Minimum conductor size1 reference - 15 Oct 2026 · 1 min readMinimum cable size for power points
AS/NZS 3000 Table 3.3 sets a minimum of 2.5 mm² copper for a socket‑outlet circuit. An exception can allow less, under conditions you must meet first.Minimum conductor size1 reference - 15 Oct 2026 · 3 min readStarting a loaded conveyor
A 22 kW conveyor that needs 120 % torque to break away. Why star-delta and a soft starter will not start it, and what a drive or autotransformer does.Motor starting methods1 reference - 15 Oct 2026 · 1 min readVoltage drop on 2.5 mm² over 30 m
20 A on 2.5 mm² copper over 30 m drops 10.81 V, which is 4.7 % at 230 V and close to the 5 % limit. The run can reach 31.91 m.Voltage drop2 references - 15 Oct 2026 · 1 min readWhat size cable for a 22 kW EV charger?
A 22 kW three‑phase EV charger on a 32 A circuit takes 6 mm² copper over 20 m, with 38 A of derated capacity and a 1.04 % drop. At 60 m it takes 10 mm².Cable size3 references - 15 Oct 2026 · 1 min readWhat size cable for a 25 A circuit?
A 25 A single‑phase circuit takes 4 mm² copper on a typical NZ route, with 29 A of derated capacity. 2.5 mm² stops at 23 A, short of the breaker.Cable size3 references - 15 Oct 2026 · 1 min readWhat size cable for a lighting circuit in NZ?
A 10 A lighting circuit in New Zealand takes 1.5 mm² copper over 30 m, with 16 A of derated capacity and a 4.3 % drop. A 16 A circuit takes 2.5 mm².Cable size3 references - 15 Oct 2026 · 1 min readWhat size cable for power points in Australia?
A 20 A power point circuit in Australia takes 2.5 mm² copper on AS/NZS 3008.1.1:2025, rated 20 A enclosed in air at 40 °C. Grouping pushes it to 6 mm².Cable size3 references - 15 Oct 2026 · 1 min readWhat size cable for power points in NZ?
A 20 A power point circuit in New Zealand takes 2.5 mm² copper enclosed in air, with 23 A of derated capacity. Ceiling insulation moves it to 4 mm².Cable size3 references - 14 Oct 2026 · 4 min readMotor circuit for a 15 kW pump: DOL or star-delta
Size a 15 kW 400 V pump circuit: cable, breaker, contactor and overload relay. Compare DOL, star-delta, soft starter and drive starts.Motor circuit3 references - 14 Oct 2026 · 3 min readTransformer secondary fault current for 500 kVA
A 500 kVA 11 kV to 400 V transformer at 6 % impedance, worked through to 721.69 A of secondary full load current and 12,028.13 A of fault current.Transformer1 reference - 13 Oct 2026 · 3 min readSubmain voltage drop estimate for a 160 A tender
A price stage check on a 160 A submain over 80 m on 70 mm² XLPE. See the mV/A·m figure, the 1.89 % drop and the length the budget allows.Voltage drop3 references - 13 Oct 2026 · 3 min readWhere can a home battery go? Garage walls
A garage wall that backs onto a bedroom, with a hot water cylinder nearby. See which AS/NZS 5139 location rules fail for a home battery, then fix each one.Battery location check3 references - 12 Oct 2026 · 5 min readKitchen power points and the cooktop zone
Place power points and switches near a cooktop, an outdoor gas bottle and a gas vent. Check each distance to AS/NZS 3000 and hand the sink to the wet area tool.Accessory location4 references - 12 Oct 2026 · 3 min readMax cable length for a 20 A C curve subcircuit
A 20 A curve C socket circuit on 2.5 mm² runs 40 m. See the Zs the engine returns, the Table 8.1 limit and the maximum length before the circuit fails.Loop impedance5 references - 12 Oct 2026 · 3 min readSubmain cable size for 3‑phase 100 A over 60 m
A 100 A tenancy submain on tray over 60 m at 40 °C. See the derating chain, the four checks and why the loop impedance check sets the size at 70 mm².Cable size6 references - 9 Oct 2026 · 4 min readDownlights in an insulated ceiling
Re-insulate a NZ ceiling with downlights in it. Check which may be covered, which only abutted, which must come out, and the clearances and roof space sign.Downlight clearance3 references - 9 Oct 2026 · 3 min readThree‑phase power: kVA to amps at 400 V
The root three relation between amps, kVA and kW on a 400 V board, worked at 50 A and a 0.9 power factor, with the kvar figure the engine returns.Three phase power1 reference - 8 Oct 2026 · 5 min read12 V caravan cable: d.c. voltage drop
A 12 V caravan feed at 30 A over 6 m, checked on 4, 6 and 10 mm² twin against the 10 % ELV limit, then a 48 V battery-to-inverter run.Voltage drop4 references - 8 Oct 2026 · 3 min read24 V DC voltage drop on an instrument loop
A 4–20 mA loop runs 200 m on 2.5 mm² at 24 V. See the mV/A·m figure, the 7.51 % drop and the maximum length the engine returns for a 10 % limit.Voltage drop3 references - 8 Oct 2026 · 3 min readFactory power factor correction: 250 kW at 0.78
A 250 kW factory load at 0.78 power factor lifted to 0.95. The kvar, the capacitor steps, the current saved, the kVA released and why the bank is detuned.Power factor correction3 references - 8 Oct 2026 · 3 min readFault level at a sub‑board, 300 kVA transformer
Work the prospective fault current at a sub‑board 45 m from a 300 kVA transformer, three‑phase and phase-earth, and check 6 kA and 10 kA breakers against it.Fault level at a board2 references - 8 Oct 2026 · 3 min readShed earthing on a 16 mm² submain
Earth a NZ shed 30 m from the house on a 16 mm² submain. Compare an earth with the submain and a separate MEN with its own rod, and when each is allowed.Outbuilding earthing5 references - 8 Oct 2026 · 4 min readSolar battery size for a family home: 25 kWh a day
Size a solar battery for a home that uses 25 kWh a day with an 8 kW array. Usable and nominal kWh, the bank, the inverter, winter solar and where it can go.Home battery4 references - 8 Oct 2026 · 5 min readThree circuits in a hot ceiling: correction factor
Three 32 A circuits in conduit across a 40 °C and a 50 °C ceiling space, worked with the NZ 2017 tables and again with AS/NZS 3008.1.1:2025.Correction factors7 references - 8 Oct 2026 · 5 min readWhat size breaker for 4 mm² cable
4 mm² copper enclosed in air takes a 25 A breaker, and 32 A fails at an Iz of 29 A. Grouping, a hot ceiling, insulation and a long run lower it.Circuit check6 references - 7 Oct 2026 · 4 min readRCD arrangement for a house board
Check a New Zealand house board of eight circuits on two RCDs. See what fails with a fourth circuit on one RCD or both lights on one, and the AU change.RCD arrangement3 references - 7 Oct 2026 · 3 min read22 kW EV charger amps at 400 V three‑phase
A 22 kW three‑phase EV charger draws 31.75 A at 400 V. See the inputs, the clause, the arithmetic and the current that feeds cable sizing and demand.Full load current2 references - 6 Oct 2026 · 4 min readTotal voltage drop: mains, submain and final
Add the voltage drop of the consumer mains, a shed submain and a final subcircuit against the 5 % limit, and fix a long submain before the shed circuits fail.Total voltage drop3 references - 6 Oct 2026 · 5 min readWire a bathroom: zones, IP ratings and the RCD
A New Zealand bathroom with a 1.6 m bath and an open shower, worked through the AS/NZS 3000 Section 6 zones, the IP each item needs, the RCD and bonding.Wet area zones5 references - 3 Oct 2026 · 3 min readGenerator sizing for a 150 kVA holiday park
A 150 kVA three‑phase standby set at 400 V gives 216.51 A full load current, 120 kW real power and 1443.38 A fault current from one nameplate.Generator current2 references - 3 Oct 2026 · 3 min readOff-grid battery bank autonomy at 48 V
A bach load list of 7600 Wh per day at 48 V needs 703.7 Ah of battery for two days of autonomy at 0.5 depth of discharge, worked step by step.Battery2 references - 2 Oct 2026 · 4 min readElectrical estimating calculators NZ roundup
A roundup of the calculators a New Zealand estimator uses at price stage, with a Table C2 fitout worked through to a demand of 102.95 A per phase.Maximum demand3 references - 2 Oct 2026 · 4 min readCable size for a 20 A heat pump circuit in summer
A 20 A heat pump circuit over 18 m in a 40 °C roof space needs 4 mm², with a derated capacity of 22.88 A and a voltage drop of 1.59 %.Cable size6 references - 1 Oct 2026 · 4 min readAmpSize vs jCalc vs free cable sizing tools
Compare AmpSize with jCalc and other free cable sizing tools. One 63 A three‑phase submain shows which checks decide a size, and what AmpSize leaves out.Cable size6 references - 1 Oct 2026 · 4 min readAS/NZS 3000 Appendix C: conduit space factor
What the conduit space factor in AS/NZS 3000 Appendix C governs, which tool reads it, and a worked 50 mm conduit that reaches 52.95 % fill against a 40 % limit.Conduit fill4 references - 1 Oct 2026 · 3 min readEV charger cable size for a 7 kW 32 A circuit
A 7 kW EV charger on a 32 A dedicated circuit over 30 m needs 6 mm², with 38 A derated capacity, 2.85 % voltage drop and 0.73 Ω loop impedance.Cable size4 references - 30 Sept 2026 · 3 min readArc flash incident energy at a 400 V switchboard
A 400 V board with 20 kA bolted fault and 0.2 s clearing gives 6.23 cal/cm² at 455 mm, an arcing current of 9.64 kA and a 1395.97 mm boundary.Arc flash4 references - 30 Sept 2026 · 4 min readAS/NZS 3008.1.2 Table 52: the k factor
What Table 52 governs, how the adiabatic check uses k, and a 10 kA fault cleared in 0.1 s that needs 22.11 mm² against an installed 25 mm² conductor.Fault rating5 references - 30 Sept 2026 · 3 min readIDMT curve grading for a 100 A feeder
Two standard inverse relays at 2000 A give a feeder trip at 0.23 s, an incomer trip at 0.99 s and a grading margin of 0.76 s, read off one chart.IDMT protection3 references - 29 Sept 2026 · 3 min readAS/NZS 3000 Tables C1 and C2: demand groups
What the demand group letters govern, when to use Table C1 or Table C2, and a commercial assessment that returns 276.26 A total and 92.09 A per phase.Maximum demand5 references - 28 Sept 2026 · 4 min readAS/NZS 3008.1.2 Tables 22 to 29: derating
What the derating tables govern, how ambient and grouping combine into one factor, and a 63 A feeder whose capacity falls to 78.85 A on 35 mm² copper.Cable size7 references - 27 Sept 2026 · 6 min readAS/NZS 3008.1.1 table numbers: 2017 to 2025
Each AS/NZS 3008.1.1 table AmpSize reads, with its 2017 number, its 2025 number and whether its values moved, and one submain that cites both sets.Cable size6 references - 27 Sept 2026 · 4 min readAS/NZS 3008.1.1 vs 3008.1.2: AU and NZ conditions
The AU part of AS/NZS 3008.1 rates cable at 40 °C air and the NZ part at 30 °C. One 32 A circuit needs 6 mm² in Australia and 4 mm² in New Zealand.Cable size6 references - 27 Sept 2026 · 4 min readAS/NZS 3008.1.2 Tables 4 to 21: current ratings
What the current rating tables govern, which table AmpSize reads today, and a 40 A circuit that lands on 10 mm² with a derated capacity of 50 A.Cable size4 references - 27 Sept 2026 · 4 min readAS/NZS 3008 Table 13 (now 3.18): multicore ratings
What AS/NZS 3008 Table 13 gives, why the 2025 AU part calls it Table 3.18, how to read its columns into the calculator, and what moved for buried cable.Cable size4 references - 27 Sept 2026 · 3 min readAS/NZS 3008 Table 22 (now 3.33): bunched grouping
AS/NZS 3008 Table 22 is the grouping table for bunched circuits, not a temperature table. The 2025 AU part calls it Table 3.33. Read it in the calculator.Cable size5 references - 27 Sept 2026 · 3 min readAS/NZS 3008 Table 27 (now 3.44, 3.45): temperature
AS/NZS 3008 Table 27 corrects a cable rating for the air or soil temperature. The 2025 AU part splits it into Tables 3.44 and 3.45 and re-derives the factors.Cable size5 references - 27 Sept 2026 · 5 min readAS/NZS 3008 vs BS 7671: cable sizing compared
How BS 7671 and AS/NZS 3000 with AS/NZS 3008.1 size a cable, where they differ, and why a BS current rating never converts into an AS/NZS one.Cable size8 references - 27 Sept 2026 · 4 min readAWG and the NEC for NZ and AU electricians
AWG sizes and the NEC set against AS/NZS 3000 and 3008.1. A gauge converts to mm², but its rating does not, and the NEC 3 % drop figure is only a note.Imperial cable5 references - 27 Sept 2026 · 5 min readDC cable size: 48 V battery and 600 V PV array
Two d.c. circuits sized to AS/NZS 3008.1.1:2025, a 48 V battery-to-inverter run that current sizes and a 600 V array feed that voltage drop sizes.DC cable size6 references - 27 Sept 2026 · 3 min readMotor full load current: 11 kW 400 V DOL
Full load current, shaft speed, torque and direct on line starting current for an 11 kW four‑pole 400 V induction motor, with the figures the tool returns.Motor3 references - 26 Sept 2026 · 3 min readConduit fill: 4 x 6 mm² singles in 25 mm
Four 6 mm² single‑core cables in 25 mm conduit, with the fill percent, the space factor and the smallest conduit the tool recommends for the bundle.Conduit fill2 references - 25 Sept 2026 · 3 min readCommercial maximum demand with Table C2
A tender-stage demand assessment for a commercial building using AS/NZS 3000 Table C2, with each group demand and the per-phase figure the tool returns.Maximum demand3 references - 24 Sept 2026 · 3 min readProspective fault current at a main switchboard
A 16 kA fault cleared in 0.1 s on 70 mm² copper XLPE, with the minimum conductor size, the withstand current and the k factor the adiabatic check returns.Fault rating3 references - 22 Sept 2026 · 3 min readAS/NZS 3000 Table 8.1: max Zs by curve and rating
Table 8.1 max Zs for a 16 A device, by curve. B allows 3.59 Ω, C allows 1.92 Ω and D allows 1.15 Ω. See why, with a 30 m circuit at 0.89 Ω.Loop impedance6 references - 21 Sept 2026 · 5 min readAS/NZS 3008.1.1:2025: what changed from 2017
The 2025 AU part adds d.c. ratings to 1500 V, renumbers every table and moves some ratings. Four circuits, each run on both editions, show what moves.Cable size6 references - 21 Sept 2026 · 3 min readVoltage rise for a 5 kW solar inverter cable
A 5 kW single‑phase inverter 40 m from the switchboard on 10 mm² copper, with the rise in volts, the percent and the maximum length the tool returns.Voltage rise4 references - 19 Sept 2026 · 3 min readAS/NZS 3000 Clause 3.6.2: voltage drop limit
What Clause 3.6.2 governs, how the 5 % budget splits across mains and subcircuits, and a 25 A run over 35 m that returns 2.6 % from the engine.Voltage drop4 references - 19 Sept 2026 · 4 min readCable size for a 32 A single‑phase 25 m run
Work through a 32 A single‑phase circuit over 25 metres in New Zealand. See every derating factor, the check that sets the size, and the result the tool gives.Cable size4 references - 19 Sept 2026 · 4 min readDomestic maximum demand with Table C1
Assess the maximum demand of a New Zealand house from Table C1, group by group, with a worked example that lands on 52.61 A on a single‑phase supply.Maximum demand2 references - 19 Sept 2026 · 4 min readEarth fault loop impedance and maximum Zs
What earth fault loop impedance measures, how the maximum Zs check works, and a 32 A circuit on 6 mm² over 25 m that lands on 0.67 ohms against a 0.96 limit.Loop impedance3 references - 19 Sept 2026 · 3 min readVoltage drop with the mV/A·m method
How the millivolt per amp metre method works, with a 32 A run over 25 metres on 6 mm² copper and the exact drop, percent and maximum length the tool returns.Voltage drop3 references
Read in order
AS/NZS 3008 tables 6 parts
- Part 1AS/NZS 3008.1.2 Tables 4 to 21: current ratings
- Part 2AS/NZS 3008 Table 13 (now 3.18): multicore ratings
- Part 3AS/NZS 3008.1.2 Tables 22 to 29: derating
- Part 4AS/NZS 3008 Table 22 (now 3.33): bunched grouping
- Part 5AS/NZS 3008 Table 27 (now 3.44, 3.45): temperature
- Part 6AS/NZS 3008.1.2 Table 52: the k factor
The 2025 edition of AS/NZS 3008.1.1 3 parts
Maximum demand tables 3 parts
Questions
- What size cable for power points in NZ?Cable size
- What size cable for power points in Australia?Cable size
- What size cable for a lighting circuit in NZ?Cable size
- What size cable for a 25 A circuit?Cable size
- What size cable for a 22 kW EV charger?Cable size
- How many amps can 1.5 mm² cable carry?Circuit check
- How many amps can 2.5 mm² cable carry?Circuit check
- How many amps can 2.5 mm² carry in Australia?Circuit check
- How many amps can 6 mm² cable carry?Circuit check
- How many amps can 10 mm² cable carry?Circuit check
- How many amps can 16 mm² cable carry?Circuit check
- Maximum Zs for a 16 A curve C breakerLoop impedance
- Minimum cable size for a lighting circuitMinimum conductor size
- How many 2.5 mm² cables fit in 20 mm conduit?Conduit fill
- Minimum cable size for power pointsMinimum conductor size
- How far can 1.5 mm² run on a 10 A circuit?Maximum circuit length
- How far can 4 mm² run on a 25 A circuit?Maximum circuit length
- How many power points on a 20 A circuit?Circuit loading
- How many lights on a 10 A circuit?Circuit loading
- Voltage drop on 2.5 mm² over 30 mVoltage drop