WPP Electrical Ltd logo
  • Established 1985over 40 years in the Borders
  • 9 full-time electriciansAll 18th Edition qualified
  • SELECT 17074 · ECA 1683735NSI, MCS, OZEV & RECC
  • £10m / £5m insuredEmployers' & public liability
  • Free fixed-price quotesSupplied free, no obligation

Service overview

Why incoming voltage is often higher than it needs to be

UK supplies are permitted to sit well above the nominal 230V, and many sites receive noticeably more than their equipment needs. Most electrical loads do not benefit from the excess, they simply consume more, run hotter and wear out sooner.

What the service covers

We log the incoming voltage over a representative period, assess the load types on site, and where the data supports it, install and commission voltage optimisation equipment at the incoming supply. The work includes the survey, sizing, installation, isolation planning, commissioning under load and post-installation verification.

Who it is for

Commercial, industrial and larger agricultural sites with a consistently high incoming voltage and substantial lighting, motor or resistive load: workshops, production units, cold stores, hospitality venues, retail premises and farm operations.

When it is needed

When logging shows the incoming voltage sitting persistently at the upper end of the permitted range, when lamp and control gear failures are unusually frequent, when motors run hot, or when you are looking for consumption reductions that do not depend on changing how the business operates.

Why professional work matters

Optimisation only pays on the right site. Voltage-dependent loads such as lighting and resistive heating respond well; modern electronically regulated equipment often does not. Anyone quoting a fixed percentage saving without logging your supply first is selling a box rather than solving a problem, and the honest answer on some sites is that the payback does not justify it.

The cost of leaving it

What a persistently high supply voltage does

Over-voltage does not trip anything. It just costs money continuously and shortens the life of the equipment it feeds.

  • Consumption you never chose

    Voltage-dependent loads draw more power at higher voltage while delivering no additional useful output. It is metered, billed and repeated every hour the site is open.

  • Shorter equipment life

    Lamps, drivers, control gear, contactors and motor windings all age faster at elevated voltage. Replacement costs and the labour to fit them rarely get attributed to the real cause.

  • Additional heat in the installation

    Higher current and higher losses mean more heat in cables, boards and motors, which is precisely what accelerates insulation ageing and termination failure.

  • Assuming it will help everywhere

    The common mistake is fitting optimisation on a site dominated by electronically regulated loads, where the saving is minimal. Without logging and a load-type assessment, the payback calculation is guesswork.

  • Undersized or badly sited equipment

    Optimisation gear installed without allowance for peak demand, ventilation or bypass arrangements becomes a single point of failure on the incomer, the worst possible place to have one.

Our process

How the job runs, start to finish

  1. 01

    Step 1: Supply logging and inspection

    We log incoming voltage and demand over a representative period and survey the installation and the load types it feeds.

  2. 02

    Step 2: Assessment and honest recommendation

    The data tells us how much headroom exists and which loads will respond. If optimisation will not pay on your site, that is what the report says.

  3. 03

    Step 3: Fixed-price proposal and sizing

    Equipment sized for peak demand with appropriate bypass arrangements, priced as a written fixed sum with the programme and isolation window stated.

  4. 04

    Step 4: Installation and commissioning

    Installed at the incoming supply during an agreed isolation, commissioned under real load, with output voltage verified across phases.

  5. 05

    Step 5: Verification and certification

    Post-installation logging confirms the delivered voltage and the change in demand, and full test certification is issued for your records.

Payment by bank transfer (preferred) or card. Deposits on larger jobs only, agreed case by case before we start.

What you get

The difference it makes on your site

Lower consumption on responsive loads

Lighting, resistive heating and many motor loads draw less at the correct voltage, with no operational change asked of your staff.

Fewer premature failures

Lamps, drivers and control gear last longer at design voltage, cutting both parts and the labour to replace them.

Cooler running installation

Reduced current and losses mean less thermal stress on cables, boards and windings across the site.

Sized from your own data

Logging comes before specification, so the equipment matches peak demand and the projected benefit is based on measurement.

Bypass designed in

Bypass arrangements are specified so maintenance or a fault on the equipment never becomes a loss of supply.

One accountable contractor

Survey, installation, commissioning and certification handled by the same SELECT and ECA approved firm that maintains the rest of your installation.

In detail

Equipment types, siting and where it applies

Optimisation is a supply-side intervention, and the value it delivers depends almost entirely on what sits downstream of it.

Fixed versus electronic optimisation

Fixed-ratio units apply a set reduction and suit sites where the incoming voltage is consistently high and stable: simple, efficient and with very little to go wrong. Electronic and variable units regulate the output as the incoming voltage moves, which suits supplies that swing across the day, at the cost of greater complexity.

Single-phase and three-phase installations

Three-phase units are installed at the main incomer and sized for total site demand, with attention to phase balance. Smaller single-phase premises can be treated where the load justifies it, though the economics are usually weaker than on a three-phase commercial or industrial supply.

Load types and how they respond

Incandescent and halogen lighting, resistive heating and direct-on-line motors respond strongly. Fluorescent and older discharge lighting responds well. LED drivers, variable speed drives, IT equipment and switch-mode power supplies are largely voltage-independent and respond little. Establishing your load mix is the single most important part of the assessment.

Siting, ventilation and bypass

Equipment is positioned close to the incoming supply with adequate ventilation and access for maintenance. Manual or automatic bypass is specified so the site can run unoptimised if the unit needs isolating, a detail that separates a considered installation from a risky one.

Combining with other energy work

Optimisation sits naturally alongside LED relamping, power factor correction, solar PV and battery storage. Sequencing matters: relamping to LED changes the load mix and therefore the optimisation case, so we assess the package rather than each item in isolation.

Commercial, industrial and agricultural application

Industrial sites benefit most where motor and lighting load is high. Commercial premises with extended trading hours and legacy lighting see meaningful reductions. Farms with large shed lighting and fan loads can benefit, though on many holdings solar PV delivers a stronger return and we will say which we would spend the money on first.

Accredited for this work

  • SELECT17074
  • ECA1683735
  • NSI Approved (Fire)NSI-000082/FS/S
  • BAFESP203 Registered
  • MCS via NAPITNEP-66400
  • OZEV ApprovedEV chargers
  • RECCRegistered
  • SMAS WorksafeSSIP approved

Before you call

Voltage Optimisation: your questions answered

How much does voltage optimisation cost?

Cost depends on site demand and equipment type. We log the supply and survey the loads first, then issue a written fixed price alongside the measured case for doing it.

How much will it save?

That depends on your incoming voltage and your load mix, which is exactly why we measure rather than quote a headline figure. Where the data does not support a worthwhile payback, we will tell you not to do it.

How long does installation take?

Installation is typically completed in a single planned isolation window, arranged out of hours where continuity matters. The programme is confirmed with the quote.

Will it affect our equipment?

Equipment is supplied within its designed voltage range, which reduces stress rather than adding it. Sizing and bypass arrangements are specified so the unit never becomes a single point of failure.

How long does the equipment last?

Optimisation equipment is long-lived with minimal moving parts, and we can include it in a planned maintenance routine so its condition and output are periodically verified.

Is it worth doing if we have already gone LED?

Often less so, because LED drivers are largely voltage-independent. That is a reason to assess the whole package together, the honest answer on some sites is that power factor correction or solar will return more.

Do you provide certification?

Yes. Full test certification and post-installation verification of delivered voltage are issued for your records, from a SELECT (17074) and ECA (1683735) approved contractor.

Do you cover emergency support?

Emergency call-outs are available. Out-of-hours calls are answered for existing customers, charged at approximately 1.5 times the standard hourly rate.

Are you insured for work on the incoming supply?

Yes: £10m employers' liability and £5m public liability, with RAMS produced for virtually all jobs and SMAS Worksafe SSIP accreditation.

Which areas do you cover?

The Scottish Borders and North Northumberland, including Coldstream, Duns, Kelso, Berwick-upon-Tweed, Eyemouth, Greenlaw, Chirnside, Jedburgh and Wooler.

Related services

Voltage Optimisation near you

Working from Unit 4 Home Pl, Coldstream TD12 4DT across the Scottish Borders and North Northumberland.

See the full list of service areas, read about the company, or return to the homepage.

Get a price

Find out if optimisation pays.We log first, sell second.

Book a supply log and load assessment. You will get a measured answer either way, and a fixed price if the numbers stack up.

01890 882981
  • Established 1985 | over 40 years' experience
  • SELECT 17074 · ECA 1683735 · SMAS Worksafe SSIP
  • £10m employers' and £5m public liability cover
  • Free quotes supplied

Request a free quote

The more detail you give us, the more accurate the price.

Keep looking

Related electrical services and areas we cover

Not sure which trade you need? Read about the family-run team behind WPP Electrical, browse recent commercial, industrial and agricultural electrical projects, or request a free fixed-price electrical quote.

Call 01890 882981Request a Quote