SWA Current Carrying Capacity

The current carrying capacity of an SWA cable will depend on the installation method adopted and the application of any relevant correction factors such as grouping or soil resistivity as a couple of examples.

The easiest way to calculate SWA cables is by using our SWA Cable Calculator.

SWA Current Carrying Capacity Tables

SWA current carrying capacity tables are listed in BS 7671, also rating factor tables for various installation methods are listed in Appendix 4 Current Carrying Capacity and Voltage Drop for Cables.

SWA current carrying capacity tables include:

Single-core armoured 70°C thermoplastic insulated cables (non-magnetic armour)
Multi-core armoured 70°C thermoplastic insulated cables
Single-core armoured 90°C thermosetting insulated cables (non-magnetic armour)
Multi-core armoured 90°C thermosetting insulated cables

16mm SWA Current Carrying Capacity Table:

CSA	SWA Clipped Direct Current Carrying Capacity (A)
1.5 mm²	23 Amps
2.5 mm²	31 Amps
4 mm²	42 Amps
6 mm²	53 Amps
10 mm²	73 Amps
16 mm²	94 Amps
25 mm²	124 Amps
35 mm²	154 Amps
50 mm²	187 Amps
70 mm²	238 Amps
95 mm²	289 Amps
120 mm²	335 Amps
150 mm²	386 Amps
185 mm²	441 Amps
240 mm²	520 Amps
300 mm²	599 Amps
400 mm²	787 Amps

SWA Cable Size Current Carrying Capacity

The ccc (current carrying capacity) of an SWA cable is the maximum amount of current the cable can withstand without melting or being subject to damage in normal service.

The maximum current carrying capacity of an SWA cable will depend on many factors, including cable size, number of cores, single phase or three phase and installation reference method.

SWA cables are available in a multitude of sizes and cores varying from 1.5 mm² up to 400 mm² and above. Calculate the required size of an SWA cable which includes current carrying capacity, voltage drop and correction factors.

SWA Cable Size Calculator

Failure to carry out a full and proper SWA cable size calculation may result in an undersized SWA cable being selected, for this, try out our Cable Calculator mobile app. To calculate voltage drop on its own try the voltage drop calculator.

When selecting an SWA cable size, in addition to checking the current carrying capacity of the SWA cable it is also important to check the voltage drop, maximum permissible Zs value of your protective device and apply any relevant correction factors.