Voltimum reports on low voltage connections to multiple occupancy buildings

Recent changes to the Gas and Electricity (Internal Markets) 2011 Regulations has led UK Power Networks to introduce a single standard for multi-occupancy buildings. How does this affect Voltimum UK users, many of whom are electricians and electrical contractors? It affects those involved in the connection of supplies to multi-occupancy buildings.

The new standard, EDS 08-0118
, entitled ‘Supplies To Multi-Occupied Buildings’, will be effective across all three of their Distribution Network Operator (DNO) regions. These are the London Power Network (LPN), the Eastern Power Network (EPN) and the South Eastern Power Network SPN).

Supplies to multi-occupied buildings have been provided by a variety of methods and arrangements in the UK Power Networks regions and across the UK. Moreover, UK Power Networks has inherited a number of different standards and practices, which can bring its own problems. The new standard aims to:

• Ensure clear ownership boundaries and responsibilities

• Provide a sound and safe system of earthing
• Ensure that an emergency fire-fighting supply is operationally effective (if provided), and that the Building Network Operator (BNO) is aware of the operational issues and options that can be chosen.

• Ensure that routine isolations and emergency disconnections are available and are operationally safe.

The scope of EDS 08-0118:

This Engineering Design Standard provides guidance on the provision of supply to multi- occupied buildings - defined by UK Power Networks as ‘a building occupied by more than one customer’ - and for fire-fighting arrangements in the SPN, LPN and EPN regions.

For multi-occupied buildings, it is necessary to determine the type of building construction (e.g. common steel frame, common steelwork and/or common metallic services), as the building construction and the installation of shared metallic services will determine the electricity supply arrangements that will be installed by UK Power Networks.

The important thing to note is that the new standard means that UK Power Networks will no longer install or maintain any new rising and lateral sub-main cabling networks within a building. The PME earthing will only extend as far as the service intake cut out and with provision for metering of the individual properties within the building.

The reason given for this is because rising and lateral cables are tied into the fabric of the building, yet the building owner needs to be able to maintain and renew the structure of the building without dependence on UK Power Networks.

From now on, the responsibility for the design, installation and maintenance of new rising and lateral sub-main cabling networks within buildings will rest with the building landlord or building owners’ nominated Building Network Operator (BNO). The BNO, which may be the building owner or any other licensed Network Operator, must now install, own, inspect, repair, maintain or replace as required the risers and laterals.

This change will have an effect on many new build or renovation projects of flats, office buildings, shopping centres, and any multi-use buildings sharing a common intake service, but this standard will not affect the ownership of existing risers and laterals.

Connection of new services above 100A:

In addition, UK Power Networks has introduced another single standard for the connection of new services above 100A.

This new standard, entitled ‘EDS 08-0143 – Customer LV Supplies Above 100A Single Phase’, gives guidance for the provision of electrical services where the new or increased load requires an agreed capacity above 69kVA up to and including 1000kVA (except Independent Distribution Networks Operators (IDNOs)) and will affect any customer applying for loads within this criteria.

It will also be applied across the same UK Power Networks regions. EDS 08-0143 was published on 1^st of October 2012 and came into effect from 1^st of June 2013.

The aim of EDS 08-0143 is to ensure the following:

• That there are clear ownership boundaries and responsibilities when installing electrical services above single-phase 100A
• That a sound and safe system of earthing is provided
• That routing isolations and emergency disconnections are available and are 
operationally safe
• That information is provided on the installation of LV supplies up to 1000kVA. 


The key changes:

The main changes introduced by EDS 08-0143 are that for new service connections above 100A there will be the introduction of Air Circuit Breakers (ACBs), including the introduction of metering CTs within the service cut out equipment rather than a separate chamber. UK Power Networks will provide clear information on the requirements of the intake location or switch room size.

Specifically:

• Air Circuit breakers (ACBs) will now be installed as standard for all three Distribution Network Operator areas (EPN, SPN, LPN) for supplies over 800A
• In the London region it will now be the responsibility of UK Power Networks to provide and install the CT metering cabinet
• New dimensions will apply for the CT metering cabinet on quotations produced after 1^st of June 2013.

Both of these new standards will, says the ECA, ‘introduce significant changes in the existing electrical power service connections practice for all UK Power Networks regions, and will affect designers, builders and electrical contractors’.

Comments the ECA: ‘The new standard for multi-occupancy building supplies has the potential for significant opportunities for ECA Registered Members to work together with BNO’s within the UK Power Networks regions’.

Links:

The new standards are published on the UK Power Networks website (www.ukpowernetworks.co.uk) and can be found at: http://library.ukpowernetworks.co.uk/library/en/g81/Design_and_Planning/Planning_and_Design/Documents/EDS+08+-+0118+Supplies+to+Multi-occupied+buildings.pdf   (see link below)

And:

http://www.ukpowernetworks.co.uk/internet/asset/9c65e873-db66-427d-a7af-dcba87ab2f4C/Customer+Supplies+above+100A.pdf (see second link below)

Reference should also be made to EDS 06-0017 for the earthing arrangements applicable to the building/s. Further guidance is available in BS 7671:2008 (2011).