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.
SWA Current Carrying Capacity
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
| 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 |
SWA Cable Size 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.
Failure to carry out a full and proper SWA cable size calculation may result in an undersized SWA cable being selected.
SWA Cable Size Current Carrying Capacity
The maximum current carrying capacity of an SWA cable varies between SWA cable sizes and number of cores.
SWA cables are available in a multitude of sizes and cores varying from 1.5mm upto 400mm and above.
