The voltage at which a particular item of plant and machinery is supplied can have a significant effect on its efficiency and operation. Historically, the supply voltage in the UK was 240-volts (phase to earth) but since European Union harmonisation regulations came into force this has been reduced to 230-volts.

In reality, there has been no change: the range of acceptable voltages has simply been widened to accommodate the lower “Continental” voltage and the actual UK limits are now 230-volts minus 6% (216.2-volts) to plus 10% (253-volts). All equipment sold within the EU has to be capable of operating throughout this range of voltages.

Numerous site investigations have shown that the supplied voltage does, in fact, vary from less than 220-volts on some sites to over 250 on others, and in some cases the statutory limits are being breached.

However, the vast majority of sites suffer from excessive voltage. This is due to the historic design of transformers that are built to provide 250-volts (433-volts phase to phase) in the no-load situation, and rely upon the site’s electrical load to bring this down to around 240 (415). As many transformer installations are over-specified the result is that the distributed voltage is invariably in excess of 240.

The voltage at an individual site can also vary considerably depending on the demand profile and any variation in the supplied grid voltage at that location. Investigation is needed at those sites that are operating at the top end of the voltage range, but may also be beneficial for sites operating at lower voltages, particularly where security of supply may be an issue.

The Green Consultancy’s Comprehensive Service

Investigate the voltage profile of a site; voltage drop; the existing supply infrastructure; the nature of the site’s demand in terms of process and plant; and the opportunities for cost-effective remedial works.
Consider both the voltage profile and the site’s kW demand profile as the highest voltages usually occur with the lowest demand and this will reduce the potential savings.
Consider the actual nature of the electrical loads as some, such as IT equipment, provide no reduction in consumption at all with a reduced voltage, whereas others may produce savings that are significantly greater than pro-rata.
Consider the cost-effectiveness of all options to reduce energy consumption.
Provide a comprehensive report detailing the recommendations; potential savings; costs; future infrastructure changes and the effect that these may have.

For your no obligation quote, or to discuss your requirements, please contact Michael Webb or phone him on 08450 176299.