Eaton MEM Circuit Protection and Control is a leading UK manufacturer of high power busbar trunking systems. These are rigid conductor systems which carry electrical power from switchboards to various load centres in modern buildings. For Bullring, Eaton MEM supplied more than 600m of its Mempower XP busbar trunking, in ratings from 1 350A to 2500A, together with associated tap-off units.

Mempower XP is a ‘low impedance’ busbar trunking system. This makes use of a special ‘sandwich’ construction of conductors and insulation which results in a compact unit with low impedance and excellent performance under short-circuit conditions, It is available in ratings up to 6300A.

Bullring is Europe’s largest city centre retail regeneration project. It includes two major department stores — Debenhams and Selfridges — together with 140 other retail units including Next, H&M, Gap, Zara, USC and Benetton, plus numerous restaurants and cafes. There is parking for over 3000 cars and direct links with New Street and Moor Street Stations and bus interchanges.

Mempower XP feeder trunking takes power from the four main switchboards (manufactured by another Eaton group company, Eaton Bill Switchgear) to seven ‘risers’ where distribution trunking takes it to the different levels of the complex. Tap-off units incorporate Memshield 2 Hi-break Adjustable moulded-case circuit-breakers; these have a 25kA fault current rating and adjustable thermal settings.

Among the advantages of busbar trunking over cable distribution is that it can follow structural profiles closely without requiring space for the bending radii of cables. Mempower XP busbar trunking features a special ‘velocity joint’ system which can be used to change height/direction without the need for specialist factory-built units. These are fully adjustable on site, covers can be measured and supplied with the busbar in situ. More than 70 velocity angle joints (right-angle joints) and velocity radial joints (joints with an angle between 0° and 90°) were supplied for Bullring. At the main switchboards, special phase-change units were installed to enable the conductors within the busbar to be orientated to align with those in the switchboards. A number of other special accessories were produced for the project. These included a 630A tap-off unit (standard tap-off units are rated bOA, 160A, 250A and 400A). A special offset 400A tap-off unit was also produced for one location.

The willingness to engineer special joints and accessories to suit the needs of the application is one of the benefits that Mempower offers over many of its competitors. Mempower engineers worked closely with site personnel with the electrical contractor, Hills Electrical & Mechanical, to coordinate supply of the busbar trunking systems and ensure that any problems were dealt with speedily as they arose.

The Bullring development is an investment by the Birmingham Alliance. Main contractor is Sir Robert McAlpine, engineering consultant is WSP Consulting Engineers and electrical contractor is Hills Electrical and Mechanical plc. Eaton Bill Switchgear was responsible for overall supply of switchgear and busbar systems.

Eaton Corporation is a global $7.2 billion diversified industrial manufacturer that is a leader in fluid power systems; electrical power quality, distribution and control; automotive engine air management and fuel economy; and intelligent drive train systems for fuel economy and safety in trucks. Eaton has 51,000 employees and sells products in more than 50 countries.