This is a new appendix that provides recommendations for the design and erection of electrical installations, including installations having local production and storage of energy for optimizing the overall efficient use of electricity.

The recommendations within the scope of this appendix apply for new electrical installations and modification of existing electrical installations. Much of this appendix will not apply to domestic and similar installations.

It is intended that this appendix is read in conjunction with the update to BS IEC 60364-8-1, expected to be published in 2018.

Principles of energy efficiency in buildings

This proposed new appendix on energy efficiency details the steps to be taken during the design process to consider the energy efficiency of an electrical installation. The implication of these changes to the electrical installation design hierarchy is broadly as follows:

Current electrical installation model:

Safety  >  Capacity  >  Resilience

New model:

Safety  >  Capacity  >  Efficiency  >  Resilience

Effectively there will be two design requirements – the first is to understand the energy profile of the building and both the passive and active measures taken within it, while the second is to undertake steps to reduce energy losses within installations.

This update will, therefore, provide a framework for clients to stipulate levels of energy efficiency, in order to achieve:

• Less impact on the environment
• Reduction of energy losses and energy cost
• Use of energy at lower tariffs
• Less reactive maintenance
• Optimisation of performance for life cycle

IEC 60364-8-1 – which is the international document the proposed update is based on – considers a number of factors for energy efficiency in electrical installations, which include:

• The efficiency placement of the electrical intake
• Electrical distribution wiring system efficiency
• Types of controls to avoid wastage
• Provision of energy measurement
• Types of loads which can be switched off without impacting safety and usability
• Electrical system energy management
• Energy efficiency impact of maintenance work

What does this mean in practice?

A good example of what energy efficiency means for the designer of an electrical installation is to consider cross-section of conductors.

Increasing the cross-sectional area of conductors will reduce the power losses. This decision can be made by assessing the savings within a time scale against the additional cost due to over-sizing. Unfortunately, to work this out, the designer will need to refer to complex calculations contained in IEC 60287-3-2.

Similar considerations can be given to power factors, harmonic currents, zones, usage, meshes etc.