Cable Size Calculator

Calculate the correct cable size for any circuit based on BS 7671:2018+A2:2022

Load Details

Enter the load as current (Amps) or power (kW)

Load Input Mode

Design Current (Ib)*

The expected current the circuit will carry

Cable Length*

Total length of cable run

Circuit Details

Phase type and circuit classification

Phase Type

Circuit Type

Determines voltage drop limit

Cable & Installation

Select cable type and installation method

Cable Type

Installation Method

Derating Factors

Ambient temperature and grouping

Ambient Temperature

°C

Reference: 30°C for standard installations

Number of Grouped Circuits

How many circuits share the same route