A concentric return cable has a conductor around the core for a return path. These are typically used for single phase systems or for single-core HV AC subsea cable circuits where specially bonded cable systems are not possible. Also DC cables may be of concentric type as is the case in an integrated return conductor cable, where the return conductor is installed around the core conductor.
| $\frac{T_1}{n_{ph}}+\left(1+\lambda_1\right) T_2+\left(1+\lambda_1+\lambda_2+\lambda_3\right) T_3$ | AC cables, or concentric return |
| $\frac{T_1}{n_{ph}}+T_2+T_3$ | DC cables up to 5 kV, not concentric return |
| $\frac{T_1}{n_{ph}}+\left(1+\lambda_1\right) T_{prot}$ | PAC/GIL |
| $\frac{T_1}{n_{ph}}+\left(1+\lambda_1\right) T_2$ | Cables subsea |
| $\frac{7}{18} T_1$ | Three-core cables in riser (Hartlein & Black) |
