Cable Sizing



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- only used for buried cables

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- if run in thermal insulation



Cable Size Calculation

Cable sizing compiles with BS 7671:2008 (IEE Wiring Regulations Seventeenth Edition) and IEC 60364:2001

Calculation Notes

Cable sizing compiles with:
 - BS 7671:2008
   IEE Wiring Regulations 17th Edition
 - IEC 60364:2001

Help and Tips

Cable size is selected as follows:

  1. Cable is calculated on current capacity
  2. Voltage drop is calculated (and cable size increased if necessary)
  3. Fault level withstand is calculated (and cable size increased if necessary)

Tip: if you don’t want fault level to be considered, you can set it to a very low value.  

Parallel Cables
Additional parallel are automatically added to group derating.  You can click the ignore checkbox to change this (for example if your cables are more than two diameters apart).

Reference Tables

Derating Factors (BS 7671):
 - Ambient Temperature, tables 4B1, 4B2
 - Grouping, tables 4C1 to 4C5
 - Protective Device, Regulation 5.1.1
 - Thermal Insulation, Regulation 523.7
 - Soil Thermal Resistivity, table 4B3

 

Resources

CPC Sizing

To select or size Circuit Protective Conductors (CPC ), please use our:
 - Circuit Protective Conductor Sizing Tool

Metric AWG Conversion

To convert between Metric and American Wire Gauge, you can use our:
- Metric AWG Conversion Table