The Silvertown Tunnel Order 2018

Retained apparatus: protection of National Grid as Electricity Undertaker E+W+S

24.—(1) Not less than 56 days before the commencement of any specified work that does not require the removal of apparatus under paragraph 21(2) (removal of apparatus) TfL must submit to National Grid a plan and seek from National Grid details of the underground extent of their electricity tower foundations.

(2) The plan to be submitted under sub-paragraph (1) must show—

(a) the exact position of the specified work;

(b) the level at which the specified work is proposed to be constructed or renewed;

(c) the manner of the construction or renewal of the specified work including details of excavation and positioning of plant;

(d) the position of all apparatus;

(e) by way of detailed drawings, every alteration proposed to be made to or close to any such apparatus; and

(f) details of any ground monitoring scheme if required.

(3) In relation to any works which will or may be situated on, over, under or within 10 metres of any part of the foundations of an electricity tower or between any two or more electricity towers, the plan to be submitted under sub-paragraph (1) must include a method statement which must in addition to the matters set out in sub-paragraph (2)—

(a) describe details of any cable trench design including route, dimensions, clearance to pylon foundations;

(b) demonstrate that pylon foundations will not be affected prior to, during and post construction;

(c) describe details of load bearing capacities of trenches;

(d) describe details of cable installation methodology including access arrangements, jointing bays and backfill methodology;

(e) provide a written management plan for high voltage hazard during construction and on-going maintenance of the cable route;

(f) provide written details of the operations and maintenance regime for the cable, including frequency and method of access;

(g) assess earth rise potential if reasonably required by National Grid's engineers; and

(h) provide evidence that trench bearing capacity is to be designed to 26 tonnes to take the weight of overhead line construction traffic.

(4) TfL must not commence any works requiring the submission of a plan under sub-paragraph (1) until National Grid has given written approval of the plan so submitted.

(5) Any approval of National Grid required in relation to a plan submitted under sub-paragraph (1)—

(a) may be given subject to reasonable conditions for any purpose mentioned in sub-paragraph (6) or (8); and

(b) must not be unreasonably withheld.

(6) In relation to a work requiring the submission of a plan under sub-paragraph (1), National Grid may require such modifications to be made to the plan as may be reasonably necessary for the purpose of securing its system against interference or risk of damage or for the purpose of providing or securing proper and convenient means of access to any apparatus.

(7) Works requiring the submission of a plan under sub-paragraph (1) must be executed only in accordance with the plan, as amended from time to time by agreement between TfL and National Grid and in accordance with such reasonable requirements as may be made in accordance with sub-paragraph (5), (6), (8) or (9) by National Grid for the alteration or otherwise for the protection of the apparatus, or for securing access to it, and National Grid is to be entitled to watch and inspect the execution of those works.

(8) Where National Grid require any protective works to be carried out either by themselves or by TfL (whether of a temporary or permanent nature) such protective works must be carried out to National Grid's satisfaction prior to the commencement of works requiring the submission of a plan under sub-paragraph (1) and National Grid must give 56 days' notice of such works from the date of submission of the plan (except in an emergency).

(9) If National Grid in accordance with sub-paragraph (6) or (8) and in consequence of the works proposed by TfL, reasonably requires the removal of any apparatus and gives written notice to TfL of that requirement, paragraphs 16 to 18 and 21 to 22 apply as if the removal of the apparatus had been required by TfL under paragraph 21(2).

(10) Nothing in this paragraph precludes TfL from submitting at any time or from time to time, but in no case less than 56 days before commencing the execution of any works, a new plan, instead of the plan previously submitted, and having done so the provisions of this paragraph apply to and in respect of the new plan.

(11) TfL is not required to comply with sub-paragraph (1) where it needs to carry out emergency works as defined in the 1991 Act but in that case it must give to National Grid notice as soon as is reasonably practicable a plan of those works and must—

(a) comply with sub-paragraph (6), (7) and (8) insofar as is reasonably practicable in the circumstances; and

(b) comply with sub-paragraph (12) at all times.

(12) At all times when carrying out any specified works TfL must comply with National Grid's policies for development near or over headlines enshrined in ENA TA 43-8 and the Health and Safety Executive's guidance note 6 “Avoidance of Danger from Overhead Lines”.

(13) As soon as reasonably practicable after any ground subsidence event, TfL must implement an appropriate ground mitigation scheme.