The Electricity Supply Regulations 1988

3.  The person concerned shall—

(a) ensure that all persons carrying out operations on any part of his electric lines are authorised persons and competent to carry out such operations;

(b) ensure that there are adequate and reliable means of communication with any interconnected owner;

(c) inform any interconnected owner of any condition, occurrence or incident which could affect the safety of that owner’s personnel or the maintenance of his lines or apparatus and shall make and keep records of such information, and when it was communicated and by, and to, whom;

(d) designate persons with authority to act and communicate on his behalf and inform every interconnected owner of the names of the persons so designated and where they may be reached;

(e) ensure that, in respect of every source of energy, there is a manually operated means of disconnection; and that the settings, if any, on any automatic means of disconnection at any point of interconnection shall not be altered without the express agreement of the owner of any lines interconnected at that point;

(f) ensure that electric lines under his control are capable of withstanding the prospective fault current associated with all sources of energy;

(g) take all reasonable precautions to limit the occurrence and effects of circulating currents in respect of the neutral points connected with earth of any interconnected systems;

(h) ensure that there are displayed at the points of interconnection or, if that is impracticable, at the nearest most appropriate place—

(i) a diagram showing all electrical infeeds and the limits of responsibility of, or control by, the respective owners;

(ii) a schedule showing by whom all apparatus connected to any of the lines so interconnected is controlled and maintained;

(iii) a schedule of agreed settings on any automatic means of disconnection; and

(iv) a description of the method of communication between persons designated for the purpose of sub-paragraph (d).