Voltage & Current Optimization is a term now commonly used to refer to the well-known energy-saving technique of reducing the electricity voltage supplied to a site in order to reduce losses in equipment.

• Voltage & Current Optimization works by reducing losses in electrical equipment – thereby reducing energy consumption, CO2 emissionsand your electricity bill!
• The lifetime of equipment is also extended (because it generally runs cooler at the reduced voltage), with a consequent reduction in maintenance costs.

Also known as “voltage-reduction”, "voltage-correction" or “voltage power optimization”, the technique has been understood for many years, and has recently received increasing interest as an effective means of reducing electricity bills, with savings of up to 15% being realised on many sites, and up to 20% on some sites.

The voltage supplied to many premises is much higher than it needs to be, leading to excessive losses in many types of equipment. This is partly because of the need to allow for voltage drops across the supply network, but is also a consequence of the harmonisation of supply voltage throughout Europe.

Supply harmonisation

The voltage of electricity supplies throughout Europe has been harmonised to 230V ± 10%, bringing the statutory supply limits to 207–253 Volts.

In the UK, the statutory supply limits have not yet been fully harmonised, with a somewhat tighter tolerance still in force: 230V +10%/-6% (216–253 Volts).

Supply voltages remain largely unchanged

The UK for many years had a standardised supply (phase-to-neutral) voltage of 240V ±6%, whereas continental Europe had a nominal supply level of 220V. Some regions used different nominal voltages (varying between 220V and 250V), but the wide tolerance of the new harmonised supply range has meant that there was no incentive for suppliers to make any real change, as the old supply limits lie almost entirely within the new limits! So the actual supply voltages have remained largely unchanged as a result of harmonisation.

The average voltage in the UK is still around 242V. (239V in Northern Ireland, 235V in the Republic of Ireland.)

This means that on the majority of sites, electrical equipment is running at a voltage much higher than needed, resulting in excessive losses.

Optimum voltage for equipment

The Institution of Electrical Engineers recommended in a 1996 report that for safety all electrical equipment needed to be tested across the range 230V +10%-14%, so all equipment produced since then should be capable of working from 198–253V. This allowed for the new lower and higher limits plus an allowance of 4% for voltage drops within the installation.

The IEE Wiring Regulations 17th Edition (BS 7671:2008), in Appendix 12 "Voltage drop in consumers’ installations", specifies a maximum value of voltage drop of 3% for lighting and 5% for all other uses, where the supply is directly from a public distribution system. (Larger drops, of 6% and 8%, are permissible with a private supply.) The implication is that electrical equipment should be able to operate over the range 230V +10%/-15% (185.5–253 Volts).

It follows therefore that there should be no problem in operating most electrical equipment within the standard supply range of 207–253 Volts.

Indeed, many items of equipment may actually have been designed to operate at 220 Volts, which was the standard voltage in most European countries until recently.

• Operating equipment at a voltage higher than really necessary can (and often does) lead to excessive energy losses in the form of heat.

The optimum voltage for a site may therefore be lower than the voltage actually supplied to the site, although the actual optimum voltage will depend on the type of equipment on the site. The primary purpose of voltage & current optimisation therefore is to reduce the voltage to this optimum level.

This is how and why BlackCurrent™ can allow you to make HUGE savings by reducing the voltage to the optimum level therefore saving you money and reducing carbon emissions.