Eaton helps keep the M1 on the move

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Eaton has supplied about 500 of its new Halyester glassfibre reinforced polyester enclosures for use in low voltage electrical feeder pillars on the M1 motorway. The pillars will supply power to lighting and communications systems between Junction 6A (the M1/M25 interchange) and Junction 10 (Luton) where a major widening programme is in progress.

The lighting feeder pillars provide power for carriageway, interchange and underbridge lighting. A typical pillar is a 100A or 200A, nine-way three-phase unit feeding up to 27 single-phase lighting circuits. The pillars have been manufactured for the lighting sub-contractor, J. McCann & Co., by Tofco Limited, a leading manufacturer of street lighting and traffic furniture.

Halyester enclosures are also used in pillars manufactured by Tofco for DW Projects ? a division of David Webster Ltd. – who are responsible for installing the motorway communications systems. These include the gantries which provide variable speed controls and variable messaging systems (?Don?t drink and drive? etc.); communications and data links with the North and South transmission stations; traffic counting mechanisms and emergency roadside telephones.

The feeder pillars are produced in various sizes in 5mm hot dip galvanised steel. EDF power supplies are brought into a chamber with a separate rear access door. Separate enclosure of components such as isolators, contactors, fuses and terminals is required to give IP66 (dust-tight and water-tight) protection of these devices and to provide electrical separation for electricians working on the feeder pillars. Eaton?s recently-introduced Halyester range of glass reinforced polyester enclosures proved the ideal solution.

?It?s a very flexible system? explains Kevin Doherty, Tofco?s National Sales Manager. The modular design means that different box sizes can be mounted neatly side-by-side, or one above another, with openings for interconnecting cables in the top, bottom or sides. For example the lighting feeder pillars typically have a 100A or 200A main switch in one Halyester enclosure, this feeds three contactors (one per phase) in a second enclosure. These then feed fuse banks in separate enclosures and a terminal chamber in yet another enclosure. There is also a separate auxiliary services box which supplies the pillar lighting, anti-condensation heater and ancillary power outlet.

Visibility of the devices and wiring within each enclosure is a major advantage according to a McCann engineer. It is frequently possible to trace a cable from one component to the next without having to open both boxes. There is no need for steel cable trunking outside the enclosures. The availability of brass gland plates that will provide adequate entry for the large 25-30mm2 single-phase outgoing cables is also important.

?Eaton?s Halyester enclosures help us build a smart, safe, high quality panel that meets all the environmental and safety requirements of our clients? says Kevin Doherty. ?The flexibility of the modular design and the range of accessories such as gland plates is a major plus-point while the cooperation of Eaton?s own engineers has contributed to a satisfying end result.?

The M1 improvement programme between Junctions 6A and 10 is being carried out for the Highways Agency by Balfour Beatty Skanska Joint Venture.

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