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 below.
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:
| CSA | Clipped Direct |
|---|---|
| 1.5 mm | 23 Amps |
| 2.5 mm | 31 Amps |
| 4 mm | 42 Amps |
| 6 mm | 53 Amps |
| 10 mm | 73 Amps |
| 16 mm | 94 Amps |
| 25 mm | 124 Amps |
| 35 mm | 154 Amps |
| 50 mm | 187 Amps |
| 70 mm | 238 Amps |
| 95 mm | 289 Amps |
| 120 mm | 335 Amps |
| 150 mm | 386 Amps |
| 185 mm | 441 Amps |
| 240 mm | 520 Amps |
| 300 mm | 599 Amps |
| 400 mm | 787 Amps |
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.
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 app, to calculate voltage drop on its own try the voltage drop calculator.
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.
To be notified of ongoing updates, news and future posts join our free Newsletter
