New Supplies

Contestable Works

What does the term ‘contestable works’ mean?

When applying for a new electricity connection – the work that is needed to be completed in order to fit a new supply can be split into contestable works, and non-contestable.

It is a strange differentiation to make, that is true. There are certain types of reinforcement works that can seriously affect the day-to-day operation of DNO networks. Because of the sensitivity and risk-potential, these works fall into the classification of ‘non-contestable’. This means that it is only the DNO who is legally able to complete these works.

The other group of work – the contestables – have emerged in response to the introduction of competition within the UK electrical distribution network. This is all of the work that can be legally completed by accredited ICPs or IDNOs. Generally speaking, the nature of work included in this category has a much lower potential for risk for DNOs.

Source: UK Power Solutions

Common terminology

We have included some of the more commonly used acronyms in this article below, to refer back to.

AcronymStands For
DNODistribution Network Operator
ICPIndependent Connection Providers
IDNOIndependent Distribution Network Operators
NERSNational Electricity Registration Scheme

What are contestable works?

Contestable works can be classified as connection works that can legally be undertaken by ICPs or IDNOs instead of just the DNO. We have created a non-exhaustive list that includes some common scenarios of contestable works:

  • Design for the network extension and any contestable reinforcement of the existing network.
  • Any procurement and provision of equipment and materials to DNO specifications for an extension.
  • Any trenching and/or preparation work for the site in question, including the circuit routes between the area of development and connection point.
  • The construction of the network extension as well as any contestable reinforcement and diversions.
  • Any recording of works completed as well as the location of cable routing and other equipment on site. The provision of this information to DNO is also included.
  • Reinstatement of the site, including circuit routes. This included both temporary and permanent.
  • Provisions for the installation of meters or metering equipment.
  • Legal consents.

Source: Enwl

What are non-contestable works?

Non-contestable work can be classified by works only legally allowed to be completed by Distribution Network Operator (DNO). This is decreed by the Electricity Act (1989) in an effort to keep customers and workers safe. We have created a non-exhaustive list that includes common scenarios of non-contestable works:

  • Processing of customer application and organisation of equipment.
  • Connection of the extension reinforced or diverted equipment to the distribution system and their energisation.
  • The process of any works needed to reinforce the distribution system where contestable work conditions are not met.
  • Any planning, design, specifying and carrying out work associated with diversion of distribution equipment where contestable work conditions are not met.
  • Any removals or repositioning of any existing electrical equipment or cables.
  • The process of agreeing and obtaining any required legal consent.
  • The operation of, repairs, and maintenance of any electrical equipment and electric cables.
  • The inspection, monitoring, or testing of any contestable work.

Source: Enwl

Non-contestable works recently opened to competition

Although the work outlined below is technically speaking non-contestable, recent changes to the competition in connections code of practice have opened this type of work up to accredited contractors.

  • Determination of the point of connection to the new distribution system.
  • Approval of contestable designs for new connections and contestable reinforcements.

Source: Enwl

What is an ICP?

An ICP (Independent Connections Provider) is a National Electricity Registration Scheme (NERS) certified company that is legally allowed to build electricity networks. Any electricity network constructions need to meet the specification and quality outlined in the agreed standards.

If you would like to search for all available ICPs then this is a handy tool to use:

What is an IDNO?

An IDNO (Independent Distribution Network Operator) is a NERS accredited company that can build their own local network. IDNOs will usually continue ownership of their local network, as-well as provide any and all ongoing network services. This usually includes most maintenance work and 24-hour fault repairs. IDNOs are connected to the DNO either directly, or through another IDNO.

Often IDNOs will step in to provide supplies to new housing, commercial developments, or rural areas – all who are not able to be supplied directly by DNO. Although IDNOs are regulated by Ofgem like others in the energy sector, their services are often associated with slightly higher prices than if they were to be carried out by DNO.

We have included a list of IDNOs within the UK later in the guide.

What can a NERS accredited ECP do?

Any NERS certified Independent Connections Provider is legally allowed to carry out work that is classified as contestable. Contracts for registered NERS providers are awarded through the contestable connections market. Once a connection has been installed, the host DNO will adopt the connection for the remainder of its lifetime. For help with identifying what work is classed as ‘contestable’ we have compiled a short list later on in this article.

Source: UK Power Networks

What is the NERS?

The NERS has been set up to allow ICPs to carry out connection work. For anybody wishing to carry out contestable connection work, they must be accredited under this scheme. Ofgem is the regulatory body for the energy industry and the ones who enforce this rule.

All DNOs on mainland UK recognise this scheme – and hold it in high regard.

The benefits of registering for the NERS are as follows:

  • Accreditation that is recognised by all UK DNOs.
  • Independent assessment and registration process.
  • Assignment of accreditation mark that will represent your achievement of incredibly high technical skills, quality and safety standards.

Source: Safety Compliance UK

List of ICPs

List of all NERS accredited ICPs in the UK
ABB Limited
Addison Project Plc
Advance Utilities (Scotland) Ltd – MURS Accredited
AG Cable Jointing Ltd
AIM Utilities Ltd – MURS Accredited
Air Utilities Ltd
AIS Utilities Ltd
AK Lighting and Signs Ltd
Alconex Infrastructure & Solutions Ltd – MURS Accredited
Alken Construction Services Ltd
ALS Civil Engineering
Altitude Services Ltd
Ameon Utilities Ltd – MURS Accredited
Amey Highways Ltd
Amey Utility Services Ltd
Andel Plant Ltd
Applebridge Construction Ltd – MURS Accredited
Approved Power Services Ltd
Aprenda Ltd
Aptus Utilities – MURS ACCREDITED
Arcadis Consulting (UK) Ltd
ARC-Tech MU Ltd – MURS Accredited
Aspire Utility Solutions
Athena PTS
Avon Utilities and Generation
Balfour Beatty Living Places
Balfour Beatty Utility Solutions
Balfour Beatty Vinci Joint Venture
Barhale Ltd
Barratt Energy
Beehive Contractors Ltd – MURS Accredited
Belac Ltd
Bethell Utility Services Ltd – MURS Accredited
BGS Ltd (Birchwood Gas Services Ltd) – MURS Accredited
Blu-3 (UK) Ltd
British Power International
Bryan J Rendall (Electrical) Ltd
Burns & McDonnell
C and P Engineering Services Ltd
C Spratt Multi UtilityLtd
C&D Resource Solutions Ltd
Cable Connections Ltd
Cable Test Ltd
Capita Real Estate and Infrastructure
Carris Utility Solutions Limited
Catsurveys Ltd
CBZ Utilities – MURS Accredited
Central Power Ltd
Centre Great Ltd
Civil and Fibre Ltd
Clancy Docwra
CNX Utilities
Compass Infrastructure UK (CI UK) Ltd
Complete Utility Solutions Ltd
Connect It Utility Services Limited – MURS Accredited
Couch Perry & Wilkes
CP Civil Engineering (UK) Ltd
Crown Highways Ltd
CS Cable Jointing
CX Utilities Ltd
DaCI Utilities Engineering Consultancy Ltd – MURS Accredited
Datom Utilities Ltd
Delta HV Power Services
Dewhurst Utility Services Ltd -MURS Accredited
Distribution Cable Jointing Ltd
DNO Consulting Ltd
DT Civils Ltd – MURS Accredited
DT Hughes Contractors
Dutton Contractors
E Donald & Associates Ltd
Eclipse Power Networks
Eco-Drill Ltd
Electrical Jointing Services
Electrical Testing Ltd
Electricity Asset Service Ltd – MURS Accredited
Electricity North West (Construction & Maintenance) Ltd
Electricity Solutions Ltd
Electricity Supply Solutions Ltd
Electricityworx Ltd
Elm Surfacing Ltd
Elmeridge Cable Services Ltd
EME Power Connections
Energetics, Design and Build Limited – MURS Accredited
Energy and System Technical Ltd (East Solutions)
Energy Assets Utilities Ltd – MURS Accredited
Energy Network Services
Engineered Systems Electrical (ESE) Ltd
Entity Power Ltd
Envevo Limited
E-ON Energy Solutions Ltd
ESM Power Ltd
eSmart networks
Estate Lighting Solutions Ltd
Eta Projects Ltd
Ethical Power Connections Ltd
Excalon Ltd
Falco Construction Ltd
Fastflow Pipeline Services Ltd
FES Support Services Ltd – MURS Accredited
Fincher Utilities Limited
Firdale Construction Ltd
First Connect Utility Solutions Ltd
FJ Infrastructure Services Limited
FM Conway Ltd
FMJ Solutions Ltd
Fosse Civil Engineering Ltd
Freedom Power Solutions
Fulcrum – MURS Accredited
Fusion JV
G2 Energy Ltd
Galldris Services (trading as Galldris Construction Ltd.)
Gas and Utility Technology Limited
Glenelly Infrastructure Solutions Ltd
GMac Utilities Ltd
GMP Contracting Services Limited
Granite Engineering Ltd
Green Frog Connect
Grid Team Services Lltd
Groom Design Services Ltd
GTC Infrastructure Ltd – MURS Accredited
H&MV Engineering Ltd
H&MV Engineering Services Ltd
Haddon Power Services
Harlaxton Engineering Services Ltd – MURS Accredited
High Voltage Engineering Services Ltd
High Voltage Substation Services Ltd
High Voltage Systems and Services (HVSS)
Highways and Konnection Services Ltd
Hilton Main Lighting & Connections Limited
Hollybox Ltd
HV Energy Systems Ltd
ICP Design Solutions Ltd
ICP Services Ltd
IDEC Technical Services (incorporating IDEC Power Services)
Infrastructure Gateway – MURS Accredited
Ingenious Power Engineering Ltd
Instalcom Ltd
Instrument and Control Services Ltd
Integrated Utility Services – MURS ACCREDITED
Integrum Power Engineering Ltd
IP (In Phase) Electrical Engineers Ltd
Ipsum Power (Licensed Networks) Limited
J Browne Developer Services Ltd
J Geraghty Limited
J Murphy and Sons Ltd – MURS Accredited
J T Utilities Ltd
J. McCann & Co. Ltd – MURS Accredited
JCM Groundworks Ltd
JK Jointing Ltd
JK Jointing Services Ltd
JN Civils Ltd
Jones Lighting Ltd
JPB Utilities Ltd – MURS Accredited
JSM Construction
Keltbray Distribution & Transmission Ltd
Kelvin Power Consultants & Kelvin Power Structures
Kier Integrated Services Ltd
Kirby Group Engineering
Kirkman Utility Services Ltd
KOR Energy Ltd – MURS Accredited
L A Clark Civil Engineering
L J Heffernan Utilities Ltd
Land and Power Ltd
Levertech HV Engineering Limited
Linbrooke Services Ltd
Live Line Power
LPC Construction Limited
LV Connections Ltd
Lydon Contracting Ltd
M and A Doocey Civil Engineering Ltd
M&M Contractors (Europe) Ltd
M.B. Power Services (Essex) Ltd
Mac Civils Ltd
Man Power Connections
Mason Street Furniture Ltd
Matrix Networks Ltd – MURS Accredited
MB Power Services (Essex) Ltd
McAndrews Utilities and Civil Engineering
MCD Utility Solutions Ltd
MDF (Services) Ltd
MDH Utility Services Ltd
Megson Utilities Limited – MURS accredited
MES Power Engineering
Metricab Power Engineering Ltd
Milestone Infrastructure Ltd
MM Miller (Wicks)
Modus Utilities Ltd
Monaghan Civil Engineering Ltd
Morgan Sindall Construction & Infrastrucuture Ltd
Morrison Energy Services
Morson Projects
Mulholland Contracts Ltd – MURS Accredited
Multi Connex Networks Ltd – MURS ACCREDITED
Multi Utility & Surfacing Ltd
Multi Utility UK – MURS Accredited
National Energy Direct – MURS Accredited
Natta Building Company Limited
NDC Utility Services Ltd
Neary Construction
Network Plus Multi Utility Ltd
Network Plus Services Limited
Network Power Connections Ltd
Networx Utilities Ltd
Nexus Utilities Ltd
NG Contracting Ltd
Nicol of Skene Ltd – MURS Accredited
NorPower Ltd
North West Multi Utilities Ltd
Novus Utility Services Ltd
O’Connor Utilities
Omnific Civil Engineering & Outdoor Electrical Ltd
Optimum Technical Services Ltd
Options Energy Group Ltd
OPUS Utility Solutions Limited
Pascon Ltd
PBU (UK) Ltd – MURS Accredited
PDI (Utilities Design and Management) Ltd – MURS Accredited
Pegasus Utilities Ltd
Pegasus Utility Services Limited
Phoenix ME Ltd
Phoenix Utilities Ltd – MURS Accredited
PI MacDonald and Son
PJ Carey (Contractors) Ltd
PJ Southall LTD
PMK Civil Engineering
Power Distribution Support
Power Jointing Distribution Services Ltd
Power Lines, Pipe & Cables Ltd(PLPC)
Power On Connections
Power One Ltd
Power Supply Projects Limited
Power Testing Ltd
PowerComm Engineering Ltd
Powersystems UK Ltd
Powerteam Electrical Services UK Ltd (trading as Omexom)
PowerTek Utilities Ltd – MURS Accredited
Prenco Professional Energy Consultants Limited t/a Prenco Utilities
Prestige Utilities Ltd
PWG Connections Ltd
Quantum Power Connections Ltd – MURS Accredited
Quartzelec Ltd
R & D Network Design
R&M Construction Services Ltd trading as R&M Lighting
Radius Utilities Ltd
RCD Utility Services Ltd
Reach Active
Renewable Energy Systems Ltd
Ringway Infrastructure Services
RJ Power Connections Ltd
RM Power Services Ltd
Roadbridge UK Ltd
Robelec Ltd
Rock Power Connections Ltd
Rogers Civil Engineering Ltd
Rosgal Ltd
S&E Engineering (Elec) Ltd
S&R Construction Ltd – MURS Accredited
Sapphire Utility Solutions Ltd
SAS Utility Services Ltd
SBS Highways Ltd
Sedona Civils Ltd
Serconnect Ltd
Shadow Utilities Ltd
Sienna Construction Ltd
Sinewave Energy Solutions Ltd
Site Energy Ltd
Skanska Construction UK Ltd
Smith Brothers Contracting Ltd
SmOp Cleantech Ltd,
SMS Energy Services Limited
SOS Electricals & Services Ltd
Sparkx Ltd.
SRM Utilities Ltd
SSE Contracting Lighting Services
SSE Enterprise Contracting (HV Services and Civils)
SSE Enterprise Utilities – (a trading name of SSE Utility Solutions Ltd Company reference 6894120)
Stone Utility Services Ltd
Success Connections Utility Consultancy & Engineering Services Ltd
Swat Security & Electrotech Systems Ltd
T&M Cable Services Ltd
Taylor Plant Ltd
TClarke Contracting Ltd.
Tesford Ltd
The Dunamis Group Ltd
The Electricity Board Ltd
Thompson Civil Engineering
Total Excavation Services Ltd
Total Utility Connections Ltd
TriConnex Ltd – MURS Accredited
Trust Utility Management Limited
UCP ChoiceLimited
UCSL (Utility Connections Solutions Limited)
UK Power Networks Services (Commercial) Ltd
UK Power Solutions Ltd – MURS Accredited
Utilex Connections Ltd
Utility Consultancy and Engineering Ltd
Utility Engineering Solutions Ltd
Utility Infrastructure Solutions – MURS Accredited
Utility Select Ltd
VIA East Midlands Ltd
Vital Energi
VolkerSmart Technologies (VST)
Voltz Power Services Ltd
VUS Limited
W & N Adams Ltd
Waitings Drainage
Walker & Watts Limited
Water & Pipeline Services Ltd
WSP UK Limited
Wyson Ltd

Source: Lr

List of IDNOs

The UK has been split into different geographical regions to be managed by DNOs. Within these geographical areas (which can be quite large) IDNOs own and operate smaller networks. These IDNO ran networks are usually extensions to the DNO network – focussing on serving new housing, commercial development, or rural areas.

We have included the current list of all registered IDNOs below:

  • Eclipse Power Limited
  • Energy Assets Network Limited
  • Last Mile Electricity
  • ESP Electricity Limited
  • Fulcrum Electricity Assets Limited
  • Harlaxton Energy Networks Limited
  • Independent Power Networks Limited
  • Leep Electricity Network Limited
  • Murphy Power Distribution Limited
  • The Electricity Network Company Limited
  • UK Power Distribution Limited
  • Utility Assets Limited
  • Vattenfall Network Limited

All of these IDNOs will be regulated in the same fashion as the DNOs. However, the IDNO licence does not have all of the same conditions as the DNO licence. IDNO pricing for customers is controlled by Ofgem (regulatory body) via ‘Relative Price Control’. This has resulted in IDNO charges being capped at a level roughly consistent with the equivalent DNO price.

Source: Ofgem

How to make your money go further

If you have just finished this article and have been left wondering what on earth all of these acronyms mean, or even just complete utter confusion – don’t worry, we are here to help.

We believe in doing things differently at Energy Solutions. We create guides like this for our customers because for too long businesses in the energy sector have hidden behind complex terminology, acronyms, and jargon. Not us.

It is a difficult ask for anybody to tackle the planning and undertaking of electrical based construction work – that is where we come in.

We have been in the business of energy for well over twenty years now, so know the ins and outs of every facet of this industry. Looking for someone to procure the best possible energy for your business? Yep.

Looking for an energy expert to advise your next move? Yep, that’s also us.

Feeling overwhelmed and just want a friendly chat with an industry professional to set your mind at ease? Of course, that’s us too.

So, if you would like to arrange a quotation for one of our services – get in touch today!

You can email us at or call us on 0131 610 1688 during all normal UK office hours.

We look forward to hearing from you!

Google Snippets

What is an ICP?

ICPs are Independent Connection Providers. They are accredited companies that can build electricity networks to agreed standards. They are owned by either a DNO or IDNO

What is an IDNO?

IDNOs are Independent Distribution Network Operators. IDNOs develop, operate, and maintain local distribution networks. IDNOs are always directly connected to the DNO directly or indirectly through another IDNO.

What is a NERS?

NERS stands for National Electricity Registration Scheme. It has been developed to allow providers (ICPs) to carry out contestable connection works. Anybody who desires to carry out this type of work must be accredited under the scheme.

What does ICP stand for?

ICP stands for Independent Connection Provider.

What does IDNO stand for?

IDNO stands for Independent Distribution Network Operator.

What does NERS stand for?

NERS stands for National Electricity Registration Scheme.

11kV Supplies

11kV, if you did not know is the main voltage used for distributing energy. For domestic and (most) business use the voltage of energy is dropped to 415 or 240V. This makes the energy safe to use and be interacted with by users (such as plugging in an appliance, so the risk of electrocution is not ridiculously high).

Larger energy users, however, will have an 11kV supply to their premises and then will own their own transformers which drop the electricity voltage so it becomes safe to use. Unfortunately, many of these transformers are old, and we mean really old.

Old electric equipment can often develop faults becoming defective just with age, so many of these transformers are inefficient and are wasting a lot of energy. Businesses will all pay for the energy they use – so even though the energy is being lost by the transformer’s ineffective practices it still counts as ‘used’. This means that many large businesses are not just wasting energy, but also money.

Especially in the current economic climate many businesses cannot be affording to lose money – especially on things which are useless and costly like wasted energy. This is where Energy Solutions can help; we can help and support you through your energy efficiency journey.

Saving you money whilst also reducing your energy consumption is what we pride ourselves on. First, let us learn a little more about what 11kV supply means, and then look at what savings can be made and why we are the best choice to help you figure out your energy efficiency.

An Intro to 11kV

In the UK, 11kV is the standard secondary distribution voltage. This is because transmitting electricity at this rate allows for a large amount of energy to be distributed at once which increases efficiency and is a cost effective option for transmitters. Additionally, the voltage is still relatively low which means the energy remains easy to manipulate and handle throughout the distribution network. This increases safety and again increases efficiency as it reduces the risk of damage or injury, slowing the process and endangering lives.

11kV is also able to be manipulated and transmitted without the need for specialist equipment or approaches; this makes it a more accessible process for workers and also saves money holistically as money is not spent on securing adequately trained staff etc. 

Substations are areas that supply the energy for a local area. Their main function as stations is to collect the high voltage energy being transmitted from the generation station and then reduce the voltage. The reduction of the voltage takes place in order to make the energy an acceptable level for local distribution. As aforementioned, this is between 240-415V. The substation consists of two main roles:

  1. simple switching between transmission lines,
  2. conversion from AC to DC (or vice versa), or from higher to lower (or vice versa) frequency

There are some main aspects of a substation which are listed below:

IsolatorThe isolator connects or disconnects the incoming circuit when the supply is already interrupted. Isolators are also used for breaking the charging current of the transmission line. An isolator is placed on the supply side of the circuit breaker so that the circuit breaker isolated from the live parts of the maintenance
Lightning ArresterThe lightning arrester is a protective device which protects the system from lightning effects. The lightning arrester has two terminals one is high voltage and the other is the ground voltage. The high voltage terminal is connected to the transmission line and the ground terminal passes the high voltage surges to earth.
CT MeteringThe metering CT measure and records the current when their secondary terminal is connected to the metering equipment panel.
Step-down TransformerThe step-down transformer converts the high voltage current into the low voltage current.
Capacitor BankThe capacitor bank consists series or parallel connection of the capacitor. The main function of the capacitor bank is to improve the power factor of the line. The capacitor bank then draws the leading current to the line by reducing the reactive component of the circuit.
Circuit BreakerThe circuit breaker interrupts the abnormal or faults current to flow through the line. A circuit breaker is a type of electrical switch which opens or closes the contacts when the fault occurs in the system.

11kV for Larger Users

As aforementioned, larger users of energy manage their own transformer which converts their 11kV supply to usable energy. However, this is largely inefficient as most transformers do not use energy effectively and often waste a lot of the money users are spending on their energy consumption.

When looking to reduce energy consumption many larger businesses will turn to green changes such as using solar panels or switching out bulbs for smart lighting methods such as dimmer switches or sensors. This is usually in a bid to reduce consumption and relieve some of the energy expenses larger users endure.

However, most of this will be wholly ineffective if such a large aspect of your energy consumption process is faulty, like most transformers are. The challenge for businesses is to look beyond the obvious, quick fixes of energy consumption and instead invest time and energy into their business to help reduce costs and limit consumption. Energy Solutions can help support any size of business in reducing their consumption and hence energy costs and have some expert advice in this particular field.

Transformer replacements can look expensive and unnecessary, often transformers are situated far away from large premises and so it is very easy to forget they exist and thus not pay them much thought when considering energy usage. Some businesses may not even understand what they are. However, that is why here at Energy Solutions we are going to leave you feeling assured and confident in the facts regarding 11kV supply.

Reasons You Should Upgrade Your Transformer

  1. Outdated and Ineffective

Many power transformers are incredibly outdated – with some estimates saying the average transformer is around 50 years old. Electrical equipment is not designed to last that long, and it will not be performing in its optimum capacity anymore. Through lost energy due to  inefficient conduct, old transformers will cost businesses a lot of unnecessary energy costs; money which, if saved, could be put to much better use within your business. Years of wear and tear have not fared transformers well and, while they served very well, the time has come for most transformers to retire and allow another to take the reins.

  • Technological Advancements

With the likes of most energy (and all) technology, transformer technology has vastly improved over the last 50 years. The significant improvements include updates such as ultra-low loss amorphous transformers. If thinking green is important to your business, as it should be, then by all means continue updating your energy consumption by investing in solar panels and other green methods, but it is also important that you invest in your transformer too. The aforementioned transformer exceeds all environmental expectations of transformers these days, and will significantly reduce energy loss and wastage – saving energy and money, and the planet!

  • Voltage Management

Time for a bit of energy jargon. Modern transformers have a lower nominal voltage of 11kV. They are typically supplied with an additional tap setting of +7.5%. This means that modern transformers serve as a cost-efficient management device because they regulate the site supply voltage at the source. This management offers users substantial savings in their energy expenses, which is always welcome!

  • Payback and Capital

Payback, typically, on a completed project will take LESS THAN 5 YEARS. That is a phenomenal turn-around on your investment! The average life expectancy of a modern transformer is 30 years. This means there are 25 years minimum where you are reaping the rewards of energy savings before reinvesting. That is such a promising payback ratio, and well worth the investment!

  • Environmental and Climate Responsibility

Many businesses are beginning to seriously tackle their carbon footprint and their environmental impact. This is really important news for the planet, and the more businesses can do the better. Transformers are a sure-fire way to ensure that your business is not just saving itself money, but also saving the planet and lives of others. Energy and carbon savings are guaranteed, and this is a very good thing for the planet. Additionally, the money you will earn in capital in the 25 years of replacing your transformer can be used to put back into your business, ensuring you have the greenest infrastructure and legislations possible. This will result is massive money and green savings for the future!

Companies such as Unilver, Arla, Rolls Royce  and United Biscuits have already saved money from upgrading their transformers. Why not reduce your energy consumption, and save money, today?

At Energy Solutions we have many services and products which will bring your business a step closer to saving money, energy, and the planet. Please do get in touch to find out how we can help and support your business today!

Building Network Operators

What is a Building Network Operator?

The recognised definition for a building network operator is as follows –

‘The organisation that owns or operates the electricity distribution network within a multiple occupancy building, between the intake position and customers installations. The BNO may be the DNO, another licensed distributor or a third party exempt from an electricity distribution license (e.g. a facilities management company)’.


Maybe a little bit wordy. From this definition we can see that building owners, landlords, developers, or whoever is in charge of the building infrastructure at a given moment all have the potential to qualify as a BNO. What is most astonishing is that often, they aren’t even aware that they are a BNO!

This isn’t a permanently fixed title, as building network operators are allowed to appoint a third party to act as the BNO on their behalf. So, even if after reading this article you find out that you are unknowingly a building network operator, it is a relatively simple fix.

Who is involved in the BNO process?

Throughout this article we will be relying heavily on the use of commonly used acronyms, if at any point you become unsure on what these mean or how they are involved in the BNO process, then it is a good idea to return to this section.

  • Distribution Network Operator (DNO): For new buildings, the responsibility of the DNO ends at the customer side of the intake. The nature of the supply does not change this.
  • Building Network Operator (BNO): Owns and operates everything past the DNO point of demarcation. This excludes any meters embedded within the network or attached to the equipment. Responsible for building and maintaining the infrastructure of the building.
  • Electricity Supplier: Owns the meters embedded within the network and provides the electricity supplied.

Scenario identification of typical BNO properties

True BNO installations usually have two unique identifying characteristics (although there are a few exceptions to this rule). Often these characteristics are revealed through universally commonly occurring scenarios.

A new electrical supply is requested for a multi-occupied building from Distribution Network Operator. No work is completed beyond the intake.If this situation occurs (specifically the lack of work past the intake point) then it is a good indicator that the property will require a BNO. Even though the DNO may offer multiple MPANs, it is still the BNO responsibility to look after supply past the intake point.
A converted property with an existing supply is confirmed by DNO to have sufficient supply for requested capacity.This situation is most common when a commercial property has been converted into apartments. There may be an existing bulk metered supply on site and the DNO may offer multiple MPANs to repurpose the existing supply for any apartments.

Other Identifying features found in BNO installations

These features are not a sure-fire way to identify BNO installations, although they are commonly found within them:

  • Fuses
  • Steel Wired Armoured (SWA)
  • Switch Fuse
  • Bus-bar Riser
  • Isolator
  • ‘Red Head’ Links
  • Distribution Board
  • Low Smoke and Zero Halogen materials.

What is a Multi-Occupied Building?

This is an important definition to make early on as there is often some confusion surrounding this term. The recognised definition for multi-occupied building is as follows –

‘Any single building that has been sub-divided into more than one premise, for example flats (including conversions) or factories that have been broken up into smaller industrial units. It includes communal areas (if any)’.

What are the basic responsibilities of a Building Network Operator?

Regardless of your background or job title, any building network operators will be responsible for the design, installation, and maintenance of the electrical installation past the intake point.

So, if there are any faults, issues, repairs, or breakages to any of the cables, boards, switches, or isolators – guess who is responsible for fixing it? You.

Building Network Operators will be expected (and legally required) to resolve any issues surrounding electrical supply, at their own cost. Maybe being a DNO isn’t such a great deal after all…

If there were to ever be a power outage for the entire building – the DNO would be responsible for restoring power. Even if there were to be a loss of supply to only one apartment or business within the building, it is still the building network operators’ job to resolve the issue.

Am I likely to be a Building Network Operator?

If you aren’t aware if you are a building network operator, it is unlikely that you will be one… The additional responsibilities that come with being a BNO make it difficult to be unaware of the position.

You are likely the designated building network operator, or at least affected by the BNO process if you are any of the following:

  • Commercial Landlord
  • Property Developer
  • House Builder
  • Property Manager
  • Electrical Contractor

The benefits of appointing a third party BNO

There are numerous reasons why you would want to appoint a third party to take over your BNO responsibilities. However, there are some discrete benefits only really available for certain parties. These are outlined in the table below.

BNO TypeBenefit
Commercial Landlords & Property ManagersIt is likely that any BNOs who have become so by acting as a landlord or property manager will have other properties on their portfolio with the same or similar responsibilities. As there will be ongoing maintenance and inspections at all of these properties, this can become a seriously time-consuming task. By appointing an external business as BNO allows them to provide this service.
Electrical ContractorsBNO offers a higher degree of freedom in terms of electrical installation and layout. By appointing an external business as BNO allows external advice, design, and project management.
Property Developers & House BuildersExternal BNO specialists are able to provide a consultancy/advice service during building, renovating, or refurbishment. This ensures that the building is industry compliant from the off.

After reading this article, I don’t want to be a DNO anymore… What can I do?

Firstly, we absolutely do not blame you!

For many, this title is simply additional (and unwanted) stress. If only there were someone out there who would leap at the chance to take on this burden…

Well, look no further!

By appointing Energy Solutions as the building network operator for your building, you will save yourself a tonne of stress (not to mention your hard-earned cash). It is often a difficult and thankless job, which is why we have decided to do something about it.

We believe in a different way of doing things to other businesses within the energy industry. We put our customers first, no matter what. Over the last twenty or so years, we have picked up the expertise needed to seamlessly oversee the responsibilities that come with being a building network operator.

If you, or someone you know is struggling with the responsibility of being a building network operator, then give us a call on 0131 610 1688.

We know how important keeping your property supplied with energy at all times is – which is why we have expanded the ways our customers can reach us. How many businesses do you know of that can communicate via WhatsApp?

We look forward to hearing from you!

Common Questions

What does BNO stand for?

BNO stands for Building Network Operator.

What is a Building Network Operator?

The standard definition of a building network operator is as follows:

‘The organisation that owns or operates the electricity distribution network within a multiple occupancy building, between the intake position and customers installations. The BNO may be the DNO, another licensed distributor or a third party exempt from an electricity distribution license’.

What do Building Network Operators do?

Building Network Operators are responsible for the design, installation, and maintenance of the electrical installations in a multi-occupied building, past the intake point. More specifically, they are expected to resolve any issues with electrical supply at their own personal cost.

Who can be a Building Network Operator?

Anybody can be a building network operator, really. The most likely reasons why someone would become a BNO is if they are any of the following; Commercial Landlord, Property Developer, House Builder, Property Manager, Electrical Contractor, or have been appointed to the position.

I don’t want to be a BNO, what can I do?

Luckily for you, it is possible to appoint a third party as the recognised building network operator for your property. It is possible to appoint someone internally (if they are willing) or also to appoint an outside business.

What are CTs? (Current Transformers)

CTs – Overview

Current transformers are measuring devices that are used to safely reproduce a low-level current that accurately represents a higher current level. They are mainly used for the purpose of metering (measuring) and protection. They come in numerous different sizes, shapes, and ratings to fit the broad range of applications.

Current transformers are not necessarily permanent installations, with smaller models and styles created especially for ease of use with temporary applications. Permanent installations usually involve slightly larger current transformers and can be found on generators, transformers, and connected loads. Permanent installations are usually required when an individual or business wants to consistently measure the current flowing in a system from a certain point, over an extended period of time.

CTs – How they work

CTs are closed loop instruments consisting of a magnetic core and a secondary winding around that core. The primary lining of the CT has the wire with the current we want to measure passed through the centre of the core.

The primary winding that carries the main current is said to have a single loop for winding. The wire produces the magnetic field that drives the current on the secondary winding which is then used as the output of the current transformer. The current of the secondary winding is proportional to the current flowing through the centre of the core.

 An example of this is as follows:

  1. Take a CT with a rating of 1000 to 5, or turns ratio of 200 to 1.
  2. 1000 amps flow through the primary circuit (primary winding).
  3. There is now 5 amps flowing through secondary winding based off of the ratio above.
  4. We can calculate the third unknown variable if the two others are known from: Ratio, primary circuit current, secondary circuit current.

CTs – Uses in the Energy Industry

As we have established already, current transformers are used mainly for metering and protection. The problem with this, is it still doesn’t lead us any closer to understanding why they are used.

Most households will be fitted with a consumption meter to measure exactly how much gas or electricity is being used over a period of time. Historically, customers would have to manually read the values of this meter and submit them to their energy supplier for billing. Over the last few years smart meters have taken over, negating the need to submit readings and providing more accurate data for billing.

But what happens when an energy supplier isn’t able to meter a supply?

This happens most commonly for business customers demanding huge quantities of energy – it is simply not possible to install one little consumption meter to measure the vast monthly consumption. In order to get around this, current transformers are fitted. This allows for an accurate measurement of consumption – without exposing anybody to unnecessary danger.

CTs – Industry jargon

The energy industry is known for having some ridiculously complex terminology, rife with jargon and interchangeable terms. It makes sense before diving any deeper to familiarise yourself with some of the relevant terms below:

CTCurrent TransformerCurrent transformers ‘step down’ electrical current to a level that normal-range ammeters can handle.
CT RatioCurrent Transformer RatioThis ratio is crucial for ensuring your meter is programmed correctly.
DAData AggregatorAgent responsible for obtaining, managing, and collating data to provide to suppliers for billing.
DCData CollectorAgent responsible for obtaining, managing, and collating data to provide to suppliers for billing.
DRData RetrieverAgent responsible for obtaining, managing, and collating data to provide to suppliers for billing.
Declared CapacityThe capacity for a new electrical supply – measured in kVA.
DNODistribution Network OperatorA company licensed to be able to distribute electricity to one (or more) of the UKs 14 distribution areas.
EACEstimated Annual ConsumptionAn estimation of how much electricity you will use over the course of a year – measured in kWh.
HHHalf HourlyHalf-hourly meters record accurate consumption data every thirty minutes.
HVHigh VoltageThe National Grid transmits energy at high voltages. High voltage electricity can cause serious harm to humans.
kVAKilo Volt AmpereThe most common unit of measurement in the energy business.
MOPMeter OperatorThe company responsible for maintenance and repairs on your meter.
MPANMeter Point Administration NumberUnique identification number for electricity supply point.
MPASMeter Point Administration ServiceOperated by Distribution Network Operator for area. They provide MPANs for new supplies.
NHHNon-Half HourlyNHH are installed at premises that do not meet the consumption threshold for a half-hourly meter.
Single or Three PhaseDifferent methods of delivering alternating current power.
Profile ClassClassification system used to describe how much energy customers will use, and when.
VT (Ratio)Voltage TransformerThis is provided by Distribution Network Operator.
WCWhole Current MeterMeter that is connected directly to a single or three phase supply cable.

CTs – Style selection

When discussing current transformers for low and medium voltage applications, there are three main style types to be aware of:

  • Solid core: These CTs are generally used for more permanent installations – used primarily for metering and protection in switchboards, panel-boards, and switchgear.
  • Split core: Used for more temporary applications. Most commonly used for power quality instrumentation.
  • Clamp-on: Used for more temporary applications. Also used most commonly for power quality instrumentation.

CTs – Six steps to power on

If you are looking to install a low-voltage current transformer metered connection at your premises, you should look to follow these six steps:

1Complete a connection agreement.
2Nominate an electricity supplier and provide them your unique MPAN.
3Appoint meter operator and inform electricity supplier.
4Arrange for a qualified electrician to install main switch and outgoing cable trails.
5Agree on an energisation date.
6Confirm that energisation date works for all involved parties.

CTs – Common ratios and fuse ratings

In order to provide some context to some of the theory, we have included some examples of common ratios and other information:

Requested kVAMaximum Fuse Rating (A)
Metering CT RatioEquivalent Max kVA

CTs – For visual learners

This article has barely so much as scraped the surface of the theory behind current transformers, there is still so much more to learn. If you are interested in finding out more about the theory behind how this technology works, but find you learn best through more visually stimulating content – then you should check out this video.

CTs – Further Information

At Energy Solutions we pride ourselves on providing the best customer-orientated service we possibly can.  We know it can be intimidating dealing with energy suppliers who hide behind industry jargon and complex terminology – so how do we solve this?

Firstly, we release in depth guides and other resources on our website for customers to gain an insight behind the scenes. We believe that energy industry literacy is the key to placing the power back into the hands of the customer.

Secondly, we provide trusted and proven expertise in energy procurement for our customers. Whether it be for a small domestic abode, or large business facility – we have it covered.

If you would like any more information on any of our services, you can look on our website or give us a call to find out more at 0131 610 1688.

We look forward to hearing from you!

Common Questions

What is a current transformer?

Current transformers are essentially measuring devices that are used to safely reproduce a low-level current that accurately represents a higher current level. They are mainly used for the purpose of metering (measuring) and protection.

How do current transformers work?

By applying Maxwell’s equations, CTs are able to reproduce a low-level current that is representative of a much higher current level. This lower level of current is measurable while the higher current is not. By measuring this lower current and combining it with a known ratio we are able to calculate the original current value.

Are there different types of current transformers?

There are a multitude of different types of transformers to choose from. Most commonly CTs come in three main style types: Split core, solid core, and clamp on.

Is it possible to remove a current transformer after installation?

Current transformers are for the most part removable. Some CTs are designed explicitly for temporary measuring and installation. It is worthwhile to spend some time researching the type of transformer installed as there are some that will be far more difficult than others.

Switch Gear Guide 2021: Circuit Breakers

If you have not heard about switchgear yet, then you need to start your research. Switchgear is an essential addition to your business to protect your expensive electrical equipment from damage.  

Circuit breakers are a form of switchgear. They are automatically operated and they behave they like the switches we use to turn lights on and off. However, instead of turning on/off when they are pushed, circuit breakers trigger when an excess of electrical current is detected. 

An excess of electrical current may occur as a result of faulty equipment within the circuit, a power cut or surge, or a short circuit. Circuit breakers detect this excess current and interrupt the current flow. This interruption protects electrical equipment further along the circuit from being affected by the overflow current.  

Passing excessive current through electrical equipment can severely damage it. This is the reason why we are advised to turn off larger electrical items connected to the mains during a power cut, to prevent damage from the power surge when the power comes back on. Circuit breakers do this automatically, and as part of the circuit, this is how they protect your equipment.  

Many businesses rely on computers and other electrical equipment heavily, and often a lot of it can be very expensive to replace. Circuit breakers help prevent replacements being necessary. This investment would save you a lot in the long term.  

Unlike a fuse, which conducts a similar function, circuit breakers can be reset. The reset can happen automatically or manually. Therefore, circuit breakers do not need to be replaced whereas fuses do. This means investing in a circuit breaker is the most cost-effective way to protect your electrical equipment because you do not have to replace the switchgear, nor the electrical equipment, in the event of an electrical current surge.  

Obviously, there are lots of variations of circuit breakers and, in this article, we are going to take a look at some of the main ones. 

Types of Circuit Breaker

A switch pole refers to the number of separate circuits that the circuit breaker controls. 

Type Abbreviation Definition 
Single Pole SP A circuit breaker which controls just one circuit 
Single Pole and Neutral SPN A circuit breaker which controls just one circuit, controlling only the hot side of the circuit. 
Double Pole DP A circuit breaker which controls two circuit 
Triple Pole TP A circuit breaker which controls three circuits 
Triple Pole and Neutral TPN A circuit breaker which controls three circuits, controlling on the hot side of each of the three circuits. 
Four Pole 4P A circuit breaker which controls four circuits 

What do Circuit Breakers Look Like? 

Circuit breakers are made in a variety of sizes.  

Small devices protect low-current circuits or sometimes individual household appliances.  

These miniature Circuit Breakers use air alone to interrupt electrical currents. 

Larger devices are designed to protect high-voltage circuits which can supply whole cities.  

Circuit breakers can terminate currents very quickly – between 30 and 150 milliseconds. This means circuit breakers act very quickly to protect your electrical equipment as wholly as possible.  

The generic, ultimate function of a circuit breaker, or a fuse, too, is to act as an automatic method of removing power (or electrical current) from  a faulty system. This is referred to as Over Current Protection Device, often abbreviated to OCPD.  

Circuit breakers are rated by two things: 

  1. the normal current they are expected to be capable of carrying,  
  1. the maximum short circuit current that they can safely interrupt.  

The latter figure will be conveyed to you via the circuit breaker’s AIC (Ampere Interrupting Capacity).  

Identifying the right circuit breaker for your specific needs may be overwhelming and confusing; that is where Energy Solutions can offer you assistance. We can advise you on your individual switchgear needs and requirements.  

How do Circuit Breakers work? 

Circuit breakers work alongside appliances, ground wires, and live wires to manage the electrical current in a building. The circuit breakers’ job is to cut off the circuit whenever it jumps above a safe level.  

Circuit breakers contain a switch, this means that it can be used more than once as the switch can just be reset. It is like your light switch; you can turn it back on (when safe to do so), it just automatically turns itself off. As aforementioned, the switch will be turned off should the circuit breaker recognise the electrical current which is passing through it to be too high.  

The Key Differences Between Fuses and Circuit Breakers 

Both circuit breakers and fuses act as switchgear which interrupts currents, but they do so in very different ways.  

Below is an overview of the differences: 

Fuses Circuit Breakers 
Replaceable Resettable 
Made of a piece of metal which melts when overheated by current, cutting off power to the circuit. Contain an internal switch which is tripped by an electrical surge, cutting off power to the circuit 
Tend to interrupt the current quicker Tend to interrupt the current slower 
Less expensive More expensive 
Prevents overheating Prevents overheating and electric shock 

Let us now take a closer look at the differences: 


Fuses stop electrical current because they typically contain filament, a thin piece of metal which connects the fuse to the electric circuit. This filament when it gets too hot. The melting of the filament breaks the circuit, and the electrical current can no longer pass through. An electrical current which is too high will be too powerful, creating a lot of heat energy which therefore melts the filament. Different types of fuses are designed to function with different levels of electrical current. When the level of current they are designed to function with is exceeded, that is when the filament will melt.  

Therefore, it is important that you are buying the correct type of fuses for your specific needs. There are different voltage and ratings available. Typically, it is advised that the best fuse option would be one which is rated slightly higher than the normal operating current within the circuit, just in case.  

Circuit Breakers 

Circuit breakers have two methods of working – the first is through the use of an electromagnet, and the second is through the use of a bi-metal strip.  

In either instance the breaker allows electrical current to flow across the metal conductor, connecting the circuit. However, when a current reaches an unsafe level for the electrical equipment within the circuit, the magnetic force of the magnet or the metal strip becomes strong enough to trip a metal lever. This metal lever throws the switch mechanism, breaking the current.  

An additional option for a circuit breaker is for the metal strip to bend. This action of bending throws the switch and breaks the connection, also. This protects the electrical equipment in the circuit by preventing the electrical current from affecting the equipment.  

Because circuit breakers contain a switch to turn off current access, the flow of electricity can be restored by just turning on/resetting the circuit breaker’s switch.  

In many domestic cases, circuit breakers are found in one space, often a cabinet, which contains a lot of individual switches (this is known as a breaker box). This allows for individual circuits to be switched off in different areas of a house, to allow for work or adjustment to wiring etc in that specific part. This is useful as it maximises the amount of the property which remains functional even during a maintenance period.  

Circuit breakers also include a ground fault circuit interrupter application. This function prevents electric shock, rather than only overheating/equipment damage. This feature is generally most useful for kitchen or bathrooms as electrical appliances tend to be nearer to water here, making the likelihood of electrocution higher should there be a power surge.  

Circuit breakers and fuses are not always interchangeable. For expert advice on which switchgear would work for your specific needs and circumstances, Energy Solutions are the best people to contact for impartial, expert advice on your energy queries.