Delivering a New 1000 kVA HV/LV Supply to a Historic Education Site
Project Snapshot
| Client | Marlborough College, Bath Road, Marlborough, Wiltshire |
| Project Value | £225,000 |
| Project Duration | Commissioned April 2019 |
| Market Sector | Commercial & Industrial – Education |
| Services Delivered | New grid connection, 1000 kVA transformer, HV/LV infrastructure |
| Powersystems Fact | Merlin was buried here! |
Marlborough College Grid Connection Case Study
Download the full Marlborough College Grid Connection Case Study to explore how Powersystems delivered a new 1000 kVA HV/LV connection and substation installation within one of the UK’s most historically significant educational sites. The PDF provides a clear overview of our 11 kV cable routing strategy, protection and metering systems, and substation fit‑out—completed with exceptional care to preserve the ancient Marlborough Mound and surrounding heritage landscape. Ideal for estates teams, consultants and engineers seeking deeper insight into a sensitive, technically demanding grid‑connection project delivered safely, efficiently and with full SSE compliance.
Client Background
Marlborough College is a renowned co‑educational independent boarding school founded in 1843, set within a site of exceptional historical significance.
The college grounds occupy the former Marlborough Castle, dating back to 1138, with the central mound believed to have Neolithic origins and linked to the legendary burial site of Merlin.
The campus includes Grade II listed parks and gardens overseen by Historic England, requiring meticulous planning and sensitivity for any civil or electrical works.
To support the new Norwood Hall utility building, the college required a modern and robust electrical connection with a 1000 kVA HV/LV supply.
The Challenge
Delivering the connection required:
- Installing 880 m of underground 11 kV cable
- Working around an archaeologically sensitive site, including the ancient Marlborough Mound
- Routing infrastructure through a historic campus with listed areas and protected landscapes
- Coordinating with SSE for point‑of‑connection tie‑ins
- Adhering to strict safety, heritage and environmental requirements
The project had to be completed without disrupting school operations or affecting the integrity of the historic grounds.
Our Engineering Solution
Powersystems provided full design, installation, testing and commissioning of the new HV/LV infrastructure, including:
- 1000 kVA 11/0.4 kV transformer
- 11 kV Trident FRMU Mk2
- 1600 A Aculok LV distribution cabinet with metering CTs
- Envico GRP enclosure
- CoP3 metering cabinet
- New earthing system
- 880 m of 11 kV cabling
- Full safety‑rule compliant energisation
As a Lloyd’s accredited ICP, Powersystems delivered both contestable and private‑wire elements, ensuring SSE would adopt the installation upon completion.
Special attention was given to underground routing to protect the Marlborough Mound — a structure dating back to c. 2400 BC — requiring Powersystems’ engineers to design a cable route that preserved the archaeological features.
Project Process
- Initial design and SSE liaison for point of connection
- Routing design around historic and protected features
- Installation of 880 m of buried HV ducting and joint pits
- Installation of transformer, HV switchgear and LV distribution
- Earthing system installation
- Testing and energisation under Powersystems Electrical Safety Rules
- Section 50 notices, licencing and traffic management for road crossings
- Handover to SSE and integration into their network
Project Facts & Figures
- £225,000 project value
- 1000 kVA 11/0.4 kV transformer
- 880 m of 11 kV cable installed
- 1600 A LV distribution cabinet
- CoP3 metering system
- New HV/LV infrastructure for Norwood Hall
- Project energised during Easter shutdown, April 2019
Technical Specifications
Electrical Plant
- 1000 kVA 11/0.4 kV transformer
- 11 kV Trident FRMU Mk2 switchgear
- 1600 A Aculok transformer‑mounted LV cabinet
- CoP3 metering cabinet
- GRP substation enclosure
Cable Infrastructure
- 880 m of 11 kV cable in buried duct routes
- Jointing pits installed across campus and road network
- New earthing system to substation standards
Compliance & Safety
- Full installation under Powersystems Electrical Safety Rules
- SSE‑approved design for adoption
- Traffic management for Pewsey Road crossing
Partnerships
- Stepnell – Main contractor
- SSE – Point of connection and network adoption
- Historic England – Indirectly involved due to heritage protections
- Specialist civils and jointing subcontractors
Key Risks & Mitigations
- Heritage Site Sensitivity – Mitigation: Cable route designed around Marlborough Mound; shallow excavation avoided; archaeological oversight.
- SSE Network Integration – Mitigation: Early liaison, coordinated tie‑ins, one‑day final connection.
- Road Crossings (Pewsey Road) – Mitigation: Section 50 management, traffic control, licencing and bonding.
- Maintaining School Operations – Mitigation: Civil work sequencing, safe access routes, Easter shutdown energisation.
Environmental Considerations
- Low‑impact routing to protect archaeological landscapes
- GRP enclosure minimising visual disruption
- Modern electrical equipment reducing energy losses
- Reduced future reliance on temporary generation
Economic & Operational Benefits
- Permanent grid connection replacing generator supply
- Improved reliability for Norwood Hall
- Infrastructure designed for future campus expansion
- SSE‑adopted system ensures long‑term operational stability
Future Prospects
With the new HV/LV infrastructure now energised, Marlborough College is well positioned to support ongoing development, facility upgrades and future electrical demand growth across the historic campus.
H2 Related Projects
- Education Sector HV/LV Upgrades
- Historic Site Electrical Infrastructure Projects
- 11 kV Private Network Installations
- SSE Point‑of‑Connection Schemes
Delivering electrical infrastructure for sensitive or historic environments?
Talk to Powersystems about HV design, grid connections and specialist installation support.