33. Contact by people or objects with high voltage equipment must be avoided. At substations the high voltage compound is protected by the provision of high security fencing and all of National Grid’s pylons have anti-climbing guards. For overhead lines a statutory minimum clearance must be maintained between conductors and the ground: the higher the voltage of the line, the greater the clearance which is required. Appendix III gives information on statutory safety clearances and on where further information and advice can be obtained.

34. Safe clearances must be maintained from buildings constructed under or adjacent to overhead lines. Safe clearances must also be maintained for trees, structures such as street lighting, new roads, and ground levels where these will be altered by civil engineering operations.

35. Underground cables give rise to particular safety requirements. The area above cables, and a distance on either side, must be kept clear of structures and trees. Access is required for maintenance and repair. It is essential that the cables and material surrounding them should not be disturbed.