Converting commercial properties into residential apartments: How to avoid a BNO insallation

Building Network Operator (BNO) installations are incredibly common in residential developments, especially when an existing building is being repurposed into apartments. Often, clients can find themselves responsible for the electrical installation without even realising it and when it was easily avoidable.

But what exactly is a Building Network Operator (BNO) installation and why is it so common in building conversions.

What is a Building Network Operator?

A ‘Building Network Operator’ is an organisation that owns the electrical installation between the ‘intake’ and the householder’s installation (their fuse board) in a property that is split into more than one home. An apartment block or a mixed-use development are prime examples.

The privately-owned infrastructure includes the distribution boards and cabling, often called ‘the laterals and risers’.

What is a BNO responsible for?

Regardless of who it is, the Building Network Operator will be responsible for the design, installation and maintenance of the electrical installation past the intake point.

In short, if there is a fault or issue with the cables, boards, switches or isolators, it is the BNO’s responsibility to resolve it, at their cost.

What are typical examples of BNO installations?

There are two predominant occurrences when you have a true BNO installation.

1. When you request a new electrical supply for a multi-premise development from your DNO, but they do not undertake works beyond the intake. UKPN covering the South East do not.

For example, you may have a mixed-use development of retail and apartments. In the offer from your DNO, they may offer multiple MPANS so each can have an individually metered supply, but the DNO’s work may stop at the main intake. In this situation, you need to arrange for an alternative contractor to install between the intake and the meter and this will be a BNO installation.

2. When you are converting a property which has an existing supply and the DNO confirms the existing supply is sufficient for your requested capacity.

For example, this is most common when a commercial property is being converted into apartments. There may be an existing bulk metered supply on site, perhaps even a substation owned by the DNO, and they offer you multiple MPANs to repurpose the existing supply for your apartments. Once again, you need to arrange for an alternative contractor to install between the intake and the meter and this will be a BNO installation.

How to avoid becoming a BNO

There is an alternative installation option which avoids you becoming a Building Network Operator. In this instance, the entire electrical connection from the distribution network through to the individually metered supplies is adopted by an Independent Distribution Network Operator (IDNO). They then taken on the responsibility for the future servicing and maintenance of the entire installation.

A great benefit of this approach is that the IDNO will offer a financial sum upon energisation (called an Asset Value) which can make a really competitive offer to the DNO doing the work.

Read more about IDNOs and asset values here.

Read more about your installation options here.


- Check the DNO’s offer letter. Does it give you the number of meters that you need? Does it refer to a Building Network Operator (BNO) installation anywhere on the offer letter or plan? If so, you will be responsible for the installation of this. Check the client responsibilities section of the offer carefully to see exactly where the DNO works stop.

- If you have an electrical contractor who is keen to do the internal works, this does not necessarily mean that your only option is for this to be a BNO installation. We can work with them to get the installation designed, approved and adopted by an IDNO with them still undertaking some of the installation. Talk to us about your options (link to contact).

- If you have no other option than to have a Building Network Operator installation, there are companies who are willing to take on the servicing and maintenance and provide a call-out service for when there is a fault. Contact us for more information and we can put you in touch.


With our experience and engineering knowledge, we successfully manage various ICP projects of varying size and scale across the UK.

By trusting Rock Power Connections with your new or upgraded electrical connection, you can rely on us to deliver your engineering solution on time and on budget.

All our customers work closely with their dedicated Rock Power Connections Project Manager to develop a programme of works that fits with their engineering requirements and is flexible to their needs.

We’d be delighted to offer you a free, no obligation, competitive quote for your electrical connection project. Please email Emma on, call 01905 456384 or click here to submit your enquiry.

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