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Eaton helps ensure essential power for Ambulance Service


The ability to supply a vital switchboard in record time helped secure Eaton the order for a new PLC-controlled main switchboard for North West Ambulance Service NHS Trust (Cheshire & Merseyside Area) as part of a major refurbishment of its electrical power supply. In a second order, Eaton supplied an emergency generator and new uninterruptible power supplies from its Powerware business.

The specification called for switchboard delivery within ten weeks of the official order. This put tight time constraints on Eaton, who were able to supply the switchboard on time and subsequently provided the diesel-generator and Powerware UPS units in the second phase of the project.

The electrical contractor, Hayes Electrical & Building Services of Paul Street Liverpool, had to install the new switchboard as a freestanding unit in such a way that the existing switchgear (a loose-mounted busbar and MEM Exel and Glasgow fuse-switches) could be removed in stages as the new switchboard became operational. A new 236kVA feeder will be provided by Core Utilities to replace the old 110kVA supply.

The new switchboard comprises essential and non-essential services sections. In the event of a power supply failure, a bus coupler opens automatically to isolate the non-essential loads. The majority of essential services are equipped with uninterruptible power supplies to ensure continuous power while the emergency generator starts up. The 150kVA diesel generator starts up automatically and loads are progressively connected, to avoid stalling.

Eaton supplied a 1,000A fully type-tested Form 4 Type 6 switchboard with a 50kA, 1 sec fault rating. Incoming and outgoing cables have top entry. The main incomer and bus coupler are both 400A MCCBs. The generator supply is provided through a 250A automatic changeover switch. A phase failure relay ensures that the generator will start up in the event of loss of supply in any phase (with the old system the generator would only start up if power was lost in all three phases).

The supply included all circuit-breakers, which are from Eaton’s new Series G range. These are generally 125A electronic MCCBs with adjustable thermal and fixed magnetic operation. Essential-side MCCBs open automatically in the event of loss of power but incorporate electronic time delays so that they re-close at 30s intervals to avoid stalling the generator. Full metering, with direct-reading instruments, is provided on all essential and non-essential circuits. Transient voltage surge suppression is also provided on essential and non-essential panels.

Hayes Electrical and Building Services is a major electrical and building contractor for the North West Ambulance Service NHS Trust. Terry Hayes, Managing Director of Hayes, says “With the technical, professional support and assistance which we have received from Eaton we have been able to install a sophisticated switchboard panel into a restricted working space. This enabled us to deliver a 21st century distribution system into a Victorian Building which houses the sophisticated Control Room Integrated Systems which the North West Ambulance Services requires and relies on to carry out their essential duties.

The equipment was supplied through the Liverpool branch of Newey & Eyre.


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