Cable Calculator

BS 7671

Circuit Parameters

Design Current (A)

Cable Length (m)

Cable Type

Supply Type

Circuit Type

Correction Factors

Ambient Temperature (Ca)

Cable Grouping (Cg)

Thermal Insulation (Ci)

Recommended Cable

2.5mm²

Current Rating

24A (derated: 24A)

Voltage Drop

10.80V (4.70%)

Calculation Details

Combined Factor

1.000

Tabulated Current

20.0A

Supply Voltage

230V

Max Voltage Drop

5% (11.5V)

All Cable Options

Size	Rating	VD	VD %	Status
2.5mm²	24A	10.80V	4.70%	OK
4mm²	32A	6.60V	2.87%	OK
6mm²	40A	4.38V	1.90%	OK
10mm²	54A	2.64V	1.15%	OK
16mm²	73A	1.68V	0.73%	OK

Calculations based on BS 7671:2018+A2:2022. Cable ratings from Appendix 4, Table 4D1A/4D2A. Voltage drop values from Table 4Ab. For final installation, always verify with manufacturer data and consult a qualified electrician.