Indian Queens private wire: 33kV cable route

The project

Ground Utilities is delivering the civils and cable installation for Novus Power's 7.8km 33kV private wire, which runs from the Tregonning Solar Farm to National Grid's Indian Queens substation in Cornwall. The route crosses farmland and Cornish hedges, passes through the village of Fraddon and follows the B3279. In all, about 46km of single-core 33kV cable is being installed. The HDD crossings are being carried out separately by the client.

Scope of works

• CDM set-up, traffic management and highway permits, including council liaison and the Section 50 licence
• Surveys, trial holes and HSG47 hand digging at 22 areas of concern
• 7.3km of open-cut trench: 3.3km in farmland and 4km in the highway
• About 46km of 33kV cable: two circuits of 3 x 630/800mm² aluminium XLPE, laid in trefoil
• 19 joint bays, fibre ducts and nine fibre chambers
• Full reinstatement of the highway, hedges and farmland

Challenges overcome

• Material delays: cable drums and ducts arrived late, so the works were re-sequenced to keep progressing.
• Winter working: trackway, ground protection and dewatering on waterlogged farmland.
• Fraddon village: 16 gas services in around 300m of narrow road, all hand dug.
• Community liaison: letter drops, access kept open and 10 bus stop suspensions.
• National Grid substation: work under National Grid safety rules and permit to work.
• Deep crossings: around 2.9m deep, beneath a high-pressure gas main and a trunk main.