CBS (Cement Bound Sand)

Cement Bound Sand (CBS) is a weak 14:1 sand to cement mix, which is predominately used as a backfill material for electrical cable installations in trenches. CBS not only protects the cable, it also reduces moisture migration removing the need to limit external cable surface temperature during the summer. Plus, due to the weak mix it can still be easily broken out if access or removal of the cable is required.



  • Compaction made easier by total water/cement ratio of 2:1
  • The mix helps to protect the cable from damage during and after installation
  • Allows for the maximum permissible conductor temperature throughout the year
  • Easily removed if required



CBS is produced to ENA TS 97-1 and NGTS 3.05.07, with the following specification requirements:

  • Grading = >95% passing a 5.0mm BS Sieve
  • Mixture = 14:1 Sand to Cement Mix
  • Dry Relative Density = >1.6Mg/m³
  • Thermal Resistivity = <1.2°C m/W
  • Void Ratio = <0.54
  • Cohesion = Appendix C