A single$-$phase cable for a $3-$phase, $132$ kV system application, is to be designed using two insulating materials A and B with peak critical breakdown stresses of $\backslash (160\backslash$mathrm$\{$kV$\}/\backslash$mathrm$\{$cm$\}\backslash )$ and $\backslash (130\backslash$mathrm$\{$kV$\}/\backslash$mathrm$\{$cm$\}\backslash )$ and corresponding relative permittivity of $4\mathrm{.}0$ and $3\mathrm{.}0$ respectively. If the conductor radius is $14$ mm $,$ determine the order and thickness of the insulation for optimum dimensions of the cable. Take a safety factor as $2\mathrm{.}2$ in the design.