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New harmonised values
UK buildings have historically operated at 240V single phase (domestic/smaller installations) and 415V in commercial (medium to large installations). In 1993 the UK voltage was harmonised with European voltages at 230 Volts with a view that manufacturers of electrical equipment would only need to make equipment that met the harmonised standard and not both. Whilst the date was made in legislation it would have been practically impossible to implement the legislation with immediate effect due to the enormous infrastructure changes required. The fix was to simply widen the voltage tolerance values to suit the disparity until such a time that the new harmonised values could be met.
In 1993 the UK voltage was harmonised with European voltages
Since that date, any new equipment installed by utility companies has been with a view to hitting these voltage-harmonised targets. The reality is, however, that large amounts of the old infrastructure are still in service and buildings are quite often seeing voltages above 240V. We occasionally see them as high 260V. Yet the manufacturers of electronic equipment make their equipment for the harmonised 230V.
This can have the effect of premature failure of the equipment due to the stresses caused by the higher voltage values along with efficiency losses dissipated as heat in the stressed equipment. A solution to this can be to reduce the voltage at the incoming supply, these need to be installed in line with regulations and if installed incorrectly these solutions can create serious issues. Most customers, (domestic, small and medium-scale commercial), do not have access to the infrastructure supplying their building and therefore have limited capability to alter the high voltage. In these cases, they should contact their local DNO who will always investigate high voltages.
Widening the voltage tolerance values
However, larger commercial customers can have access to their own transformers which control the voltage entering the building. In these cases, there can be significant savings made by swapping out the transformers or sometimes by simply altering transformer settings. These alterations can only be done by properly trained high-voltage qualified personnel and require specialist knowledge. Whilst we do not have the in-house operatives capable of making these changes we can through our network of industry contacts and trusted partners make the relevant arrangements to enable the changes required.
Please note that the Solar PV inverters have been designed to allow tolerances of +/- 10% on the grid supply, and at installation should be commissioned with the correct country code to enable the inverter to monitor the voltage accurately.
Accelerate Loss of Mains Change Program (ALOMCP)
If you have received any correspondence from the National Grid and have not taken any action, please contact us, we can assist you with this