PURPOSE AND SCOPE

All perimeter security fencing shall comply with "The Electricity Safety, Quality and Continuity Regulations 2002" as a minimum standard. These minimum standards, relevant British Standards and/or Eurocodes should be used as a reference when the item is not covered or superseded by this technical specification.

The function of perimeter security fences is to provide a deterrent, physical barrier and potential alarm against intruders. The perimeter fence shall be robust to give long delay times for access/egress for person's intent on unauthorised access.

This technical specification is applicable to the design and construction of perimeter security fencing for the following:

• The perimeter of all new build (green or brown field) substations and other operational compounds, e.g. cable sealing end compound.

• Any existing site where the perimeter security fencing is to be replaced in its entirety

• Any partial modification, extension or repair to the perimeter of an existing (non Critical National Infrastructure) site

Site boundary or demarcation fences are not covered by this technical specification. However, High Voltage (HV) segregation fences are covered.

The purpose of this technical specification is to provide National Grid's minimum security requirements for perimeter security fencing. The specification details the required functions of the perimeter security and operational compound fences with respect to three categories of substation security risk as stated below:

• Category 3- Reduced

• Category 2- Standard

• Category 1- Enhanced

It also gives the minimum acceptable standards for important features of the fence and attachments.

The location and/or strategic importance of certain sites will necessitate additional security features. The identities of such Critical National Infrastructure (CNI) sites are not available in the public domain and their individual requirements will be identified on a site by site basis as necessary and incorporated into the project specification accordingly. National Grid Group Security shall be engaged during the project development stage in order to facilitate this assessment process and confirm whether a site is CNI rated.

CNI specifications are not included in this technical specification. In the event of a site being designated as CNI, reference shall be made to NG security for the specification.