Homeowner guide
Anong laki ng cable ang kailangan ng shed, hot water cylinder o EV charger.
- 3 min basahinHomeowner shed supply voltage drop over 60 mA 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.
- 5 min basahinOhm's law on a 3 kW water heater elementWork 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.
- 5 min basahinRCD tripping with no fault: add up the leakageAn 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.
- 5 min basahinWhat size generator for a dairy shedSize 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.
- 3 min basahinFixed heating maximum demand with Table C1Adding 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.
- 2 min basahinA circuit chart for a house board with solarThe 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.
- 3 min basahinHot water cylinder cable size for a 3 kW elementA 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 percent voltage drop.
- 2 min basahinIP ratings for an outdoor point and a hosed shedWhich 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.
- 3 min basahinReading the wiring in an older houseA 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.
- 1 min basahinHow 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.
- 1 min basahinHow 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.
- 1 min basahinHow 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.
- 1 min basahinHow 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.
- 1 min basahinHow 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.
- 1 min basahinHow 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.
- 1 min basahinMinimum cable size for a lighting circuitAS/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.
- 1 min basahinMinimum cable size for power pointsAS/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.
- 1 min basahinWhat 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.
- 1 min basahinWhat 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.
- 1 min basahinWhat 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.
- 1 min basahinWhat 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.
- 3 min basahinWhere can a home battery go? Garage wallsA 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.
- 5 min basahinKitchen power points and the cooktop zonePlace 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.
- 4 min basahinDownlights in an insulated ceilingRe-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.
- 5 min basahin12 V caravan cable: d.c. voltage dropA 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.
- 3 min basahinShed earthing on a 16 mm² submainEarth 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.
- 4 min basahinSolar battery size for a family home: 25 kWh a daySize 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.
- 5 min basahinWhat size breaker for 4 mm² cable4 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.
- 4 min basahinRCD arrangement for a house boardCheck 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.
- 4 min basahinTotal voltage drop: mains, submain and finalAdd 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.
- 5 min basahinWire a bathroom: zones, IP ratings and the RCDA 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.
- 3 min basahinOff-grid battery bank autonomy at 48 VA 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.
- 3 min basahinEV charger cable size for a 7 kW 32 A circuitA 7 kW EV charger on a 32 A dedicated circuit over 30 m needs 6 mm², with 38 A derated capacity, 2.85 percent voltage drop and 0.73 Ω loop impedance.
- 4 min basahinDomestic maximum demand with Table C1Assess 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.
Mga calculator na ginagamit ng mga guide na ito
- Voltage drop calculatorKalkulahin ang voltage drop sa cable run at tingnan ang limit.
- Ohm's law at powerAnumang dalawa sa V, I, R at P ay magbibigay ng iba pang dalawa.
- RCD standing leakage budgetGaano karaming standing leakage ang kayang dalhin ng isang RCD.
- Generator sizing mula sa load listI-size ang generator mula sa load list kasama ang motor starting.
- Maximum demand calculatorI-estimate ang maximum demand para sa domestic o non‑domestic loads.
- Switchboard circuit chartGumawa ng board circuit chart at ang mga label na kailangan nito.
- Cable size calculatorHanapin ang pinakamaliit na cable size na pumapasa sa bawat check.
- IP rating chart at decoderI-decode ang IP code at hanapin ang pinakamababang kailangan para sa lokasyon.
- Gabay sa kulay ng electrical wireHanapin ang kulay ng wire para sa fixed wiring at cord, luma at bago.
- Maximum circuit length calculatorPinakamahabang run na pinapayagan ng voltage drop at ng fault loop.
- Pagsusuri ng umiiral na circuitTingnan ang naka-install na circuit: cable, device, drop at Zs.
- Circuit loading calculatorBilangin ang mga point na kayang dalhin ng final subcircuit.
- Minimum conductor size lookupHanapin ang pinakamaliit na conductor na pinapayagan para sa circuit.
- Battery location checkerTingnan kung saan puwedeng ilagay ang home battery ayon sa AS/NZS 5139.
- Power point location checkPower point malapit sa cooktop, gas cylinder, vent o lababo.
- Downlight clearance checkIC, CA90 o Non‑IC: puwede bang dumikit ang insulation sa ilaw?
- Outbuilding earthingI-earth ang shed: earth kasama ang submain, o sarili nitong MEN.
- Solar battery calculatorI-size ang home battery para sa solar evening load.
- RCD arrangement checkTingnan ang mga circuit kada RCD at ang lighting split.
- Total voltage drop calculatorIdagdag ang drop ng mains, submain at final laban sa 5 %.
- Wet area zones checkerHanapin ang Section 6 zone, IP at RCD malapit sa tubig.
- Battery bank calculatorKalkulahin ang capacity at autonomy ng battery bank para sa isang load.