Maentwrog Sub Station

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The contract involved the construction of a new control building, 132 KV transformer compound and a 60M retaining wall for Scottish Power. The site was contained within a live hydro electric station bordering the River Dwyryd. Phase 1 of the contract involved the identification of all buried services within the works, which varied from LV 415 volt to 11KV and 33 KV circuits. Cable diversions were then constructed to divert the circuits around the works to allow the cut for the construction of the 60M retaining wall. Phase 2 incorporated the construction of the new control room, 132 KV compound and associated external works. The works consisted of providing a full construction package from inception to final handover.

The schemes involved the following work elements:

  • Demolition of existing reinforced concrete structures
  • High voltage cable diversions
  • 60M long reinforced concrete retaining wall
  • Reduced dig excavation
  • Construction of 300mm thick reinforced concrete raft foundation and walls
  • 132 KV compounds consisting of 2 No reinforced concrete transformer plinths with watertight bunds and reinforced concrete bases
  • Reinforced concrete blast wall
  • Power floated slab, service trenches and cable pits
  • Fabrication and installation of galvanised support steelwork to 33kv cells
  • Cavity wall brickwork
  • Pre cast concrete roof slabs
  • Flat roof construction
  • Internal decoration
  • First and second fix plumbing and joinery to control building.
  • Reinforced concrete access roads
  • External works and 33kv transformer plinth and watertight bund to be completed on return visit