--- title: "Site Power HV/LV Electrical Design" ocid: "ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954" canonical_url: "https://d3tenders.com/contract/?ocid=ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954" markdown_url: "https://d3tenders.com/contract/ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954.md" json_url: "https://d3tenders.com/contract/ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954.json" source: "Contracts Finder" current_stage: "Tender" buyer: "SIZEWELL C LIMITED" published: "2026-08-10" --- # Site Power HV/LV Electrical Design Buyer: SIZEWELL C LIMITED Current stage: Tender OCID: ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954 [View canonical contract page](https://d3tenders.com/contract/?ocid=ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954) [Download OCDS JSON](https://d3tenders.com/contract/ocds-b5fd17-5642bf1a-b723-42dc-8746-99883c580954.json) ## Summary Sizewell C Limited has initiated a tender for the "Site Power HV/LV Electrical Design," focusing on developing a comprehensive electrical distribution network to support the tunnel construction at the SZC site. The project is located in the East of England, UK, and pertains to the services category, specifically electrical power systems design. The tender process is currently active, as of 10th August 2026, with the tender period ending on 18th August 2026. The procurement seeks expertise in delivering HV and LV electrical designs, including substations and site lighting, compliant with British Electrical safety standards. The total contract value ranges between £50,000 and £100,000, with the contract commencing on 20th November 2026 and concluding on 12th February 2027. This tender presents significant opportunities for businesses specializing in electrical and mechanical engineering services, particularly those experienced in designing and implementing electrical systems for large-scale infrastructure projects. Companies, including SMEs, that can deliver high-voltage and low-voltage network designs, substations, and comprehensive site lighting, will find this tender particularly beneficial for business growth. The project requires close coordination with the Sizewell site team to ensure compatibility with existing systems, offering unique prospects for firms knowledgeable in electrical engineering within the energy and infrastructure sectors. ## Notice The HV/ LV electrical design is essential to develop a robust and safe electrical distribution network within the Tunnel Launch Compound (TLC), the STP, SXB, SMT areas within the Temporary Construction Area (TCA) and the Ancillary Construction Area (ACA) to support tunnel construction at the SZC site. The network will be required to distribute power to the following areas and equipment: Underground: Tunnel boring machines (TBMs), Slurry pump system Underground Conveyor belt system Ventilation system Lighting & Communication networks Ancillary tunnel construction equipment Overground: Ventilation system Cooling water system Overground conveyor belt system Overground slurry pump system Compressed air system Grout batching plant Dewatering system & water treatment plant Gantry cranes Site lighting, access control & communication systems Office building/ welfare Ancillary site activities Electrical loading details of the equipment listed above will be collated and provided by CWA to the selected electrical design engineers. The design will be required to comply with current British Electrical safety legislation. Key Deliverables: HV network design - Provide the design for the distribution of the 11kV network that feeds the TLC, TCA & ACA compounds complete with associated switchgear, cable sizing, cable routes and containment systems. Provide protection settings of circuit protective devices for safe disconnection of the supply under fault conditions. Stage 4 drawings complete with associated schematics to be provided of proposed cable routes, ducting sizing/ routes, substation locations. The design will need to be agreed with the CWA/ Sizewell site team to ensure power demands and circuit configurations are compatible with the wider HV network on site. Substation design - The design and specification of the substations complete with earthing design to distribute and transform where necessary the main 11kV supply that will be used to supply the above listed compounds. Where LV (690v/400v) supplies are required, suitably sized transformers to be specified to provide sufficient power for the supplied equipment. Stage 4 drawings complete with associated schematics to be provided of substations. LV Network - Provide the design for the distribution of LV network to supply required equipment/ plant with associated switchgear, cable sizing, cable routes and containment systems to required areas of distribution. Provide protection settings of circuit protective devices for safe disconnection of the supply under fault conditions. Stage 4 drawings complete with associated schematics to be provided of proposed cable routes, substation/feeder pillar locations, MDU sub main distribution locations. Site Lighting - Provide site lighting design to provide adequate lighting for site activities. Stage 4 drawings complete with associated schematics to be provided of lighting locations and specifications. ## Key Details | Field | Value | | --- | --- | | Publication source | Contracts Finder | | Latest notice | https://www.contractsfinder.service.gov.uk/Notice/8b23e699-4fcd-43eb-b901-a40d77868aeb | | Notice type | Tender Notice | | Procurement type | Standard | | Procurement category | Services | | Procurement method | Not Specified | | Procurement method details | Not specified | | Tender suitability | SME | | Awardee scale | Not specified | | All stages | Tender | ## Dates | Field | Value | | --- | --- | | Publication date | 10 Aug 2026 | | Submission deadline | 18 Aug 2026 | | Future notice date | Not specified | | Award date | Not specified | | Contract period | 20 Nov 2026 - 12 Feb 2027 | | Recurrence | Not specified | ## Values | Field | Value | | --- | --- | | Tender value | £100,000 | | Lots value | Not specified | | Awards value | Not specified | | Contracts value | Not specified | ## Status | Field | Value | | --- | --- | | Tender status | Active | | Lots status | Not specified | | Awards status | Not specified | | Contracts status | Not specified | ## Buyer | Field | Value | | --- | --- | | Main buyer | SIZEWELL C LIMITED | | Locality | LONDON | | Post town | West London | | Postcode | W1T 4EZ | | Country | England | | ITL 1 | TLI London | | ITL 2 | TLI3 Inner London - West | | ITL 3 | TLI36 Camden | | Local authority | Camden | | Electoral ward | Bloomsbury | | Westminster constituency | Holborn and St Pancras | | Delivery location | Not specified | ## CPV Codes ### Divisions - 65 - Public utilities - 71 - Architectural, construction, engineering and inspection services ### Codes - 65320000 - Operation of electrical installations - 71314100 - Electrical services - 71321000 - Engineering design services for mechanical and electrical installations for buildings - 71323100 - Electrical power systems design services - 71334000 - Mechanical and electrical engineering services ## Release History - 10 Aug 2026 at 13:10 - Tender - Tender Notice - https://www.contractsfinder.service.gov.uk/Notice/8b23e699-4fcd-43eb-b901-a40d77868aeb ## Documents - https://www.contractsfinder.service.gov.uk/Notice/8b23e699-4fcd-43eb-b901-a40d77868aeb 10th August 2026 - Opportunity notice on Contracts Finder - https://www.competefor.co.uk/business/viewOpportunityDetailsSupplier.html?id=117177066 Please follow this link to view the notice. ## Provenance This Markdown file is an alternate public rendering of the D3 Tenders contract record. 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