BS 7671 (the IET Wiring Regulations)

Calculators that use it

• Cable size calculator

  Example: Smallest size that passes: 6 mm² (indicative)

• EV charger load calculator

  Example: Needs load management or a DNO check (total 77.2 A on a 60 A fuse)

• Extractor fan size calculator

  Example: Fan: at least 15 l/s (54 m³/h)

• Maximum demand and diversity calculator

  Example: Maximum demand: about 70.6 A after diversity (indicative)

• Voltage drop calculator

  Example: Voltage drop: 9.00 V (3.91%)

• Amps, kW and kVA converter

  Example: 32.00 A = 7.36 kW = 7.36 kVA

• Consumer unit and RCBO planner

  Example: 16 modules needed (indicative)

• Max Zs and expected Zs calculator

  Example: Expected Zs: 1.05 Ω (indicative)

• Solar PV system size calculator

  Example: 10 panels, 4.30 kWp: about 3,655 kWh a year (indicative)

• Underfloor heating calculator

  Example: 100.0 W/m² (1500 W); 100 m of pipe

• Home battery size calculator

  Example: Battery: about 5.33 kWh nominal (4.80 kWh usable)