The London Connection

The London Connection is the name given to the city’s tunnel, 20 km long and three metres in diameter.

It houses a 400 kv electricity transmission cable circuit, the highest voltage on National Grid’s transmission system. This enabled National Grid customers such as London Electricity to meet the increasing demand for electricity in and around the capital for years to come.

Charcon Tunnels won the £10 million order from contractor J Murphy & Sons to supply tunnel and shaft rings. Charcon chose Hanson to supply 50,000 tonnes of a pre-mixed blend of ordinary Portland cement (OPC) and pulverised fuel ash (PFA), to the European standard EN 197–1, as a CEM II/B-V 42,5N cement.