One of the largest medical centres in Somerset has cut its power bill by more than 11% through the simple installation of a compact Marshall-Tufflex Voltis ECO voltage optimisation unit.

Busy East Quay Medical Centre in Bridgwater serves 14,700 patients on a multi-disciplinary site that employs some 130 people and includes an operating theatre, opticians, dental surgery and chiropodist, all of which are now benefitting from significantly lower voltage levels and reduced power bills.

The Voltis ECO unit (measuring 435mm x 600mm x 275mm) was installed in a day by Forest Electrical, of Illminster, with the necessary power down for final connections scheduled for a weekend when the practice was closed. The payback period is calculated to be less than three years.

“Installation was quick and simple, made easier by the unit’s compact size,” said Alison Croft, of Forest Electrical, an E-PRO Approved electrical contracting company. “Post installation analysis of the unit after just four months is showing a saving of 11.2% on the cost of electricity used on site. This is on track to support our predicated saving of 11.5% per annum.”

Practice manager Rachel Stark is impressed with the result: “In overall practice budget terms the monetary savings are not huge but, as a proportion of our spend on electricity, and in terms of return on investment, this is really impressive. In the NHS we particularly need to ensure we are as efficient as possible in using our resources – including time – and Voltis ECO enables us to save money with almost no need for time on our part.”

Marshall-Tufflex’s efficient and cost-effective Voltis ECO range uses multi-tap transformers allowing installers to adjust the ratio by which the transformer drops the voltage on site. Installers can select one of three pre-set tappings – 10%, 8% or 6%. For East Quay Medical Centre Forest Electrical selected a 6% tapping. Should Mains voltage levels on site change significantly this tapping can be adjusted.


Forest Electrical has worked with East Quay Medical Centre for a number of years and it was through this close relationship and prior work assisting with the implementation of a site energy reduction plan that discussions turned to voltage optimisation.

Ms Stark admitted they were ‘a little sceptical’ when first told about VO but trusted their electrical contractors, who have previously installed PV panels at the medical centre through their sister company Solar Systems: “They have been outstanding in the past in terms of service, advice and products for our solar panels. So, when they told us about Voltis ECO I knew it was worth considering. The installation had to be done during a weekend and took some time because we have a lot of electrical equipment that needs to stay on or be powered down in a specific way. The install team was very flexible and helpful, ensuring they worked around us.”

Voltage optimisation was particularly suitable for the site because of its high incoming Mains voltage, which peaked at 247Volts during monitoring. “High voltages are known to cause unnecessary heating of equipment, which can in turn lead to damage and a reduction in the lifespan and operating efficiency of appliances,” added Ms Croft. “In a medical practice the equipment is far more sensitive and more expensive to replace. Optimising the site voltage to 220Volts was an obvious way to reduce unnecessary equipment damage as well as lowering operating running costs.”


Forest Electrical initially performed a desktop study for the practice, based on historical electrical usage and its own knowledge of the premises. This enabled it to predict the feasibility of, and potential savings from, voltage optimisation (subject to site monitoring). It predicted an 11.5% saving and a payback period of less than three years.

In depth analysis of the site’s electrical supply was also required to ensure the correct VO unit was specified. A Sinergy e-Tracker sub-meter was installed without disruption to the incoming supply and left in situ to monitor usage. Information obtained during this extensive period of datalogging, found the incoming voltage was high, peaking at 247Volts. By tracking the 3 phase supply over time, Forest Electrical was also able to obtain sufficient load profile data for the practice. Utilising this information, its knowledge of the site and known future plans for extending patient services, it specified the 200Amp Voltis ECO unit to suit the current demands of the practice and allow for future increase in demand whilst also providing a cost-effective solution for the client.