Engineer 份指南
为工作检查设计、生成依据并比较候选电缆截面。
- 阅读约 4 分钟Car-park floodlight: obtrusive light at a boundaryTwo 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.
- 阅读约 3 分钟Generator fault current calculation at 400 VA 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.
- 阅读约 3 分钟IEEE 1584-2002: arc flash model and limitsWhat 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.
- 阅读约 5 分钟Arc flash at a 48 V home batteryClass 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.
- 阅读约 3 分钟IEC 60255-151: IDMT curve constantsWhat 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.
- 阅读约 3 分钟Arc flash boundary at a motor control centreArcing 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.
- 阅读约 4 分钟Switchboard fault rating at 25 kA for 1 sA 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.
- 阅读约 3 分钟DC isolator rating for a 10 kW solar arrayRate 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.
- 阅读约 3 分钟Solar string sizing for a 600 V inverterHow 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.
- 阅读约 3 分钟Starting a loaded conveyorA 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.
- 阅读约 4 分钟Motor circuit for a 15 kW pump: DOL or star-deltaSize a 15 kW 400 V pump circuit: cable, breaker, contactor and overload relay. Compare DOL, star-delta, soft starter and drive starts.
- 阅读约 3 分钟Transformer secondary fault current for 500 kVAA 500 kVA 11 kV to 400 V transformer at 6 percent impedance, worked through to 721.69 A of secondary full load current and 12,028.13 A of fault current.
- 阅读约 3 分钟Factory power factor correction: 250 kW at 0.78A 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.
- 阅读约 3 分钟Fault level at a sub‑board, 300 kVA transformerWork 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.
- 阅读约 4 分钟AmpSize vs jCalc vs free cable sizing toolsCompare 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.
- 阅读约 3 分钟Arc flash incident energy at a 400 V switchboardA 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.
- 阅读约 4 分钟AS/NZS 3008.1.2 Table 52: the k factorWhat 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.
- 阅读约 3 分钟IDMT curve grading for a 100 A feederTwo 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.
- 阅读约 6 分钟AS/NZS 3008.1.1 table numbers: 2017 to 2025Each 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.
- 阅读约 4 分钟AS/NZS 3008.1.1 vs 3008.1.2: AU and NZ conditionsThe 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.
- 阅读约 5 分钟AS/NZS 3008 vs BS 7671: cable sizing comparedHow 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.
- 阅读约 5 分钟DC cable size: 48 V battery and 600 V PV arrayTwo 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.
- 阅读约 3 分钟Prospective fault current at a main switchboardA 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.
- 阅读约 5 分钟AS/NZS 3008.1.1:2025: what changed from 2017The 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.
- 阅读约 3 分钟Voltage rise for a 5 kW solar inverter cableA 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.
- 阅读约 4 分钟Earth fault loop impedance and maximum ZsWhat 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.
- 阅读约 3 分钟Voltage drop with the mV/A·m methodHow 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.
本指南使用的计算器
- 干扰光检查器依据 AS/NZS 4282，检查边界窗处的室外照明干扰光。
- 发电机电流计算器根据发电机的 kVA 求出满载电流和故障电流。
- 电弧闪络计算器估算电弧闪络能量及其个人防护装备类别。
- 蓄电池电弧闪络与等级蓄电池 DVC、危险等级、电弧闪络能量及个人防护装备等级。
- IDMT 选择性计算器绘制反时限过电流继电器的动作曲线。
- 电缆短路耐受计算器检查导体能否承受故障电流。
- 光伏隔离开关与接地计算器核定光伏阵列电缆、直流隔离开关及接地。
- 光伏组串计算器光伏组件每串数量、组串电流及隔离开关。
- 电动机启动方式对比比较 DOL、星三角、软启动和变频启动。
- 电动机回路计算器单台电动机的电缆、断路器、接触器和过载保护。
- 变压器计算器计算变压器满载电流和阻抗。
- 功率因数补偿计算器求出提高功率因数所需的电容器 kvar。
- 短路电流水平计算器根据电源计算配电箱处的预期短路电流。
- 电缆截面计算器求出通过各项检查的最小电缆截面。
- 直流电缆截面计算器按电流和电压降为最高 1500 V 的直流电缆选型。
- 电压升高计算器计算分布式发电或光伏的电压升高。
- 接地故障回路阻抗计算器对照最大 Zs 检查接地故障回路阻抗。
- 电压降计算器计算电缆线路的电压降并检查限值。