MEM Supplies
its biggest-ever switchgear order

In a multi-million pound contract, Eaton MEM Circuit Protection and Control is
supplying its largest-ever switchgear order to electrical contractor, Phoenix
Electrical Company Ltd, for the new 42-storey Cesar Pelli tower at 25
Canada Square, Canary Wharf, London.

The project, which includes nine 11kV/415V packaged substations (mainly 3.5MVA) and 28 switchboards (up to 4000A), demonstrates the ability of Eaton MEM Circuit Protection and Control to provide a comprehensive package of medium and low voltage switchgear.

It includes 11kV vacuum switchgear from Holec (another Eaton Electric company) and MEM low voltage switchboards and panelboards. Some products, such as the 18 cast resin transformers, have been sourced from outside the MEM group.

The building is supplied by nine packaged substations, installed at different levels - one in the basement, six at level 15 and two at level 42. Four of these provide landlord's services and five supply tenants' services.

The substations have been designed specially for the project by MEM. Incoming 11kV supplies are controlled by 600A Holec lnnovac SVS vacuum circuit-breakers. The substations are double-ended, with a 3.5MVA 11kV/41 5V cast resin transformer at each end. Force cooling can increase the transformer rating to 4.5MVA.

Each transformer feeds a 6300A busbar system via two manually-operated 6300A MEM air circuit-breakers, divided by a third ACB bus-section switch. Outgoing feeders are air circuit-breakers ranging from 400A to 5,000A. To meet the space constraints of the project, MEM designed a special cubicle which would allow three air circuit-breakers to be stacked vertically.

The transformers and their enclosures were delivered to site separately. The enclosures were delivered in "flat-pack" form, with the front, back, sides and base packed in wooden crates. The top section, with busbars, was pre-fabricated at MEM's Premier Street factory, in Birmingham.

Essential services design is critical to a building of this nature. MEM has designed and supplied three main essential services switchboards and 17 essential services panelboards for the building. In the event of loss of mains supply, standby generators feed the three switchboards. The essential services panelboards are normally fed from the packaged substations, via automatic transfer switches; in an emergency these transfer the load to the standby generators via the essential services switchboards.

The switchboards and panelboards are Memform and Memform SD units incorporating a combination of outgoing Memshield 2 MCCBs and combination fuse switches. Incoming devices range from ACBs to switch disconnectors.

MEM is also supplying eight special switchboards for tenants' supplies.

Meanwhile, in the neighbouring building at 8-16 Canada Square, the company is completing one of the largest busbar trunking orders ever placed in Europe. When completed, the two new towers, both 42 storeys and 200m (660ft) high, will be the tallest buildings in Canary Wharf, after the 50-storey, 244m (800ft) Canary Wharf tower at One Canada Square. The two new towers are being built by Canary Wharf Contractors Ltd. and will be leased to major International banks.