IEC 60364-8-1 standard: the state-of-the-art for Energy Efficiency in electrical installations

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IEC 60364-8-1 is part of the IEC 60364 series of standards and enhances Parts 1 to 7 with the introduction of requirements and recommendations to design the electrical installation which provides the best compromise between the required level of service and safety, and the lowest electrical consumption.

It is applicable for both greenfield and brownfield projects and should be implemented throughout the life cycle of the facility.

The first edition of Part 8-1 of the IEC 60364 standard was released in October 2014. It has recently been updated, with a second edition released in February 2019.

EC 60364-8-1 edition 2 gives requirements and recommendations for the design of an electrical installation with an energy efficiency approach. This emphasizes the importance of Energy Efficiency in the design of electrical installations, in the same way as safety and implementation rules.

In manufacturing industry, Energy Efficiency can easily be defined by the quantity of energy (kWh) necessary to manufacture one product. For an electrical installation in a building particularly, Energy Efficiency is defined as a system approach, which objective is to optimize the use of electricity. This includes:

  • Minimize energy losses,
  • Use electricity at the right time and at the lower cost,
  • Maintain the performance all along the installation life cycle.
Fig. K7 – Implementation of Energy Efficiency as per IEC60364-8-1

Here are the main points to keep in mind while implementing Energy Efficiency approach in an electrical installation:

  • There must be no conflict with the requirements relative to safety of people and property,
  • There must be no deterioration of electrical energy availability,
  • It is applicable to new and existing installations,
  • It can be implemented anytime, the only point of consideration being the rhythm of investment,
  • This is an iterative approach and improvements can be incremental. The ROI is the decision factor for implementation of new equipment dedicated to Energy Efficiency.

Technical guidance is provided on the design principles, taking into account the following aspects:

  • Optimal location of the HV/LV substation and switchboard by using the barycenter method (see also chapter MV and LV architecture selection guide for buildings),
  • Reduction of the wiring losses, by increasing the c.s.a. of cables and by implementation of Power Factor Correction and Harmonic mitigation,
  • Determination of meshes or zones with equipment having similar energy requirements,
  • Load management techniques,
  • Installation of control, metering and monitoring equipment.

What’s new in the 2019 Edition of the Standard?

Energy efficiency classes

Similar to the popular grading of consumer goods, the objective of the IEC 60364-8-1 standard is to define the efficiency classes for a building’s electrical installation based on their level of efficiency.

The standard defines 6 classes, from EE0 to EE5.

  • EE0 is given for buildings with the worst efficiency
  • EE5 is given for the best.

The classification depends on the type of building: for a given total number of points, the energy efficiency class will be different whether the building is used for residential, industrial, commercial or infrastructure purposes.

A Normative methodology to assess the energy efficiency classes of a building

The standard states 23 parameters to be evaluated, amongst 5 categories of possible improvements of the energy efficiency.

  • Category #1: Initial Installation
  • Category #2: Energy Management
  • Category #3: Performance Maintenance
  • Category #4: Power Monitoring
  • Category #5: Bonus

Each assessed parameter receives points according to its own scoring grid.

Fig. K8 – Electrical Installation Efficiency Classes assessment - extract from IEC 60364-8-1 edition 2

A Normative area for improvement of the energy efficiency class

Throughout the IEC 60364-8-1 document, best practices to improve the energy efficiency of electrical installations are presented.

Assessing the energy efficiency class using Annex B’s content also helps understand which energy efficiency-related parameters should be improved first, and which measures should be adopted to improve the grade of these parameters. See also Fig. K10 which illustrates the iterative process for electrical energy efficiency management, as described in IEC 60364-8-1.

Figure K9 below (Figure 1 of IEC 60364-8-1, 2019 edition) illustrates how to implement the electrical energy management system within the installation:

Step 1 = the inputs from the user shall be taken into account, such as the building temperature set point,
Step 2 = all sources of energy are considered, based on availability and real time price,
Step 3 = inputs from environmental data are taken into account to avoid inappropriate decisions, such as switch on the light during the day,
Step 4 = inputs from the load are extracted as they are key to verify the accuracy of the load profile,
Step 5 = detailed information on energy consumption are provided to the user,
Step 6 = decisions are taken relative to the loads such as load shedding,
Step 7 = decisions are taken relative to the sources of energy in order to deliver the service to the user at the lowest cost.

Fig. K9 – Energy Efficiency and load management system

Practical considerations to achieve Energy Efficiency - active and passive energy efficiency

Whilst it is currently possible to obtain energy savings of up to 30%, this potential reduction can only really be understood in terms of the differences which exist between active and passive forms of energy efficiency.

Passive energy efficiency is achieved by such measures as reducing heat loss and using equipment which requires little energy.

Active energy efficiency is achieved by putting in place an infrastructure for measuring, monitoring and controlling energy use with a view to making lasting changes. (see Fig. K10).

Fig. K10 – Energy efficiency solutions based on the life cycle

Savings from 5% to 15% may be easily obtained by implementation of passive energy efficiency. Typical measures include decommissioning redundant systems, use of high efficiency motors and lighting, Power Factor Correction. More significant savings can be achieved by implementation of active energy efficiency measures.


  • Up to 40% on energy for motors by using control and automation mechanisms to manage motorized systems,
  • Up to 30% on lighting by introducing an automated management mechanism based on optimal use.

Active energy efficiency does not require highly energy-efficient devices and equipment to be already installed, as the approach can be applied to all types of equipment. Good management is essential for maximum efficiency – there is no point in having low-consumption bulbs if you are going to waste energy by leaving them switched on in empty rooms!

It is important to remember, however, that savings may be lost through:

  • Unplanned/unmanaged downtime affecting equipment and processes,
  • A lack of automation/adjustment mechanisms (motors, heating)
  • A failure to ensure that energy saving measures are adopted at all times.

In addition, when the operator’s electrical network is expected to undergo frequent changes given the activities in which it is involved, these changes should prompt a search for immediate and significant optimization measures.

Approaches to energy efficiency also need to take other parameters into account (temperature, light, pressure, etc.), since, assuming energy is transformed without any losses, the energy consumed by a piece of equipment may exceed the useful energy it produces. One example of this is a motor, which converts part of the energy it consumes into heat in addition to mechanical energy.