ABSTRACT
Basic cable calculation is a simple process providing electricians follow the correct sequence of steps. Once the method of cable installation has been decided, it is time to look at selecting the correct type and size of cable that will be suitable for the job. Of course, the type of cable used will depend on the installation, but the procedure for calculating the correct size is pretty much the same for all cables. It is really important, however, that the correct tables from the wiring regulations are used, particularly the tables from Appendix 4 of BS 7671. After the cable size has been calculated, the next stage of the circuit design is to confirm that the circuit protection will operate within the required time in the event of an earth fault or a short circuit. This chapter provides the installation method for flat twin and earth.
