According to IEC 60287-2-1 for a single group of cables and IEC 60287-2-2 for more than one group of cables. The wall clearance $e_{wall}$ is the distance between the closest cable to the wall and the object clearance $e_{hor}$ and $e_{ver}$ is the horizontal and vertical distance between two objects. Both values are relative to the outer diameter of the object.
Aditions to IEC 60287-2-1 have been made:
| Id | Installation | Factor Zbs | Ebs | gbs | Clearance wall | objects |
|---|---|---|---|---|---|---|
| 1 | 1 object | 0.21 | 3.94 | 0.6 | 0.3 | 0 |
| 2 | 2 objects touching, horizontal | 0.29 | 2.35 | 0.5 | 0.5 | 0 |
| 4 | 2 objects touching, vertical | 1.42 | 0.86 | 0.25 | 0.5 | 0 |
| 6 | 3 objects touching, horizontal | 0.62 | 1.95 | 0.25 | 0.5 | 0 |
| 10 | 3 objects touching trefoil | 0.96 | 1.25 | 0.2 | 0.5 | 0 |
