Frequently Asked Questions

Below are some of the most common questions about voltage optimisation and the VO4 products. If you cannot find the answers to you questions on this page please use the buttons below to send us your questions.

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Single Phase FAQ’s


Does it really matter that my voltage is high?

The higher the voltage the higher the energy consumption. In addition, higher voltage tends to increase the heat generation in motors, and generally reduces the life expectancy of electrical equipment, including lighting bulbs.

As the majority of European electrical equipment is designed to run at the 220V nominal, all electrical equipment is designed using parameters such as voltage, frequency, capacity, etc.

Therefore, to ensure that these are operating at their optimum performance, they need to operate as close as possible to their design characteristics.


Will VO4 work in my home?

Voltage optimisation is a recognised technology that is particularly relevant in the UK, as power supplied by the National Grid often exceeds the recommended operating voltages for much of the household appliances in a common home.


How is VO4 installed?

The VO4 unit fits in-line with your current electricity unit and does not require any rewiring or any change of electricity provider. See more information on the VO4 installation page.


What is voltage optimisation?

Voltage optimisation is an electrical energy saving technique which is installed in series with the mains electricity supply to give an optimum supply voltage for the site’s equipment. Voltage optimisation improves power quality by balancing phase voltages and filtering harmonics and transients from the supply.


Where can I purchase a VO4 unit?

You can purchase a VO4 system from a network of stockists and distributors throughout the UK.


What does the VO4 unit do?

The VO4 unit is a voltage optimisation device designed for use in homes and small businesses. The VO4 system optimises the incoming voltage to a constant 220V giving householders and small businesses immediate and significant energy savings for the whole premises with a single VO4 fitted prior to the consumer unit (fuse box)


How will it be installed?

The VO4 unit will be installed between the meter and consumer unit by a qualified electrician and will regulate voltage to the whole premises.


How can I find someone to install the VO4 unit?

A list of qualified electricians can be found at Alternatively call us and we will provide you with some details local to you.


How much energy will the VO4 unit save?

Through the verified savings results gathered from our installations to date the VO4 unit saves 10%  on annual electricity bills and reduces the carbon footprint of a household by 400g per year.


Has the VO4 unit been field tested?

It has indeed, a VO4 system has also been independently tested and verified by leading energy supplier RWE Npower. Full details are available to download from our website;



Why is VO4 a worthwhile investment?

Energy prices look certain to rise and many people are concerned both about this and their carbon footprint. Fitting a VO4 unit will reduce usage and energy bills without any other changes in the way you use power in your home or business premises.


Will I be required to change my fuse board

No, the VO4 unit is installed before the fuse board (consumer unit) and does not require this to be changed or re-wired


 Three Phase FAQ’s


What level of savings and payback can I expect to see?

Savings vary depending on the equipment on site but typically we see between 8%-12% savings on electrical consumption and payback periods generally under three years.


How long does a VO4 three phase unit take to install?

Typically installation takes around 2-3 hours and will need a power shut down of around 30 minutes.


My maximum demand is over 72kVA, what do I do?

Larger voltage optimisation units are available from our sister company Powerstar


Can the VO4 unit be installed outside?

The unit is made to be installed internally but if space is tight inside we can supply an IP65 rated external enclosure (additional costs apply)


How does VO4 work with reductive and resistive loads?

Voltage optimisation works best on inductive loads – motors and lighting for example – and significant savings can be achieved on motors in particular, especially if these are not loaded at 100% of their capacity for 100% of the time.  On resistive loads voltage optimisation will help the load conserve power which will extend the life of the electronics.