IEC 60364-8-1:2019

IEC 60364-8-1 ®
Edition 2.0 2019-02
INTERNATIONAL
STANDARD
colour
inside
Low-voltage electrical installations –
Part 8-1: Functional aspects – Energy efficiency
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IEC 60364-8-1 ®
Edition 2.0 2019-02
INTERNATIONAL
STANDARD
colour
inside
Low-voltage electrical installations –

Part 8-1: Functional aspects – Energy efficiency

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.020.01; 27.015; 91.140.50 ISBN 978-2-8322-6510-9

– 2 – IEC 60364-8-1:2019 © IEC 2019
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 10
3.1 General . 10
3.2 Electrical energy management . 11
3.3 Energy measurement . 12
3.4 Sectors of activities . 13
3.5 Abbreviated terms . 13
4 General . 14
4.1 Fundamental principles . 14
4.1.1 Safety of the electrical installation . 14
4.1.2 Availability of electrical energy and user decision . 14
4.1.3 Design principles . 14
4.2 Energy efficiency assessment for electrical installations . 15
4.2.1 General . 15
4.2.2 Action plan following an assessment according to Annex B . 15
5 Sectors of activities . 15
6 Design requirements and recommendations . 15
6.1 General . 15
6.2 Determination of load energy profile. 16
6.3 Determination of the transformer and switchboard location with the
barycentre method . 16
6.4 HV/LV substation . 16
6.4.1 General . 16
6.4.2 Optimum number and location of HV/LV substations . 16
6.4.3 Working point of the transformer . 17
6.4.4 Efficiency of the transformer . 17
6.5 Efficiency of local production and local storage . 17
6.6 Losses in the wiring . 17
6.6.1 Voltage drop . 17
6.6.2 Cross-sectional areas of conductors . 17
6.6.3 Power factor correction . 18
6.6.4 Reduction of the effects of harmonic currents . 18
7 Determination of the zones, usages and meshes . 18
7.1 Determining the zones . 18
7.2 Determining the usages within the identified zones . 19
7.3 Demand response . 19
7.4 Determining the meshes . 19
7.4.1 General . 19
7.4.2 Meshes . 20
7.4.3 Criteria for considering meshes . 20
7.5 Driving parameters. 21
7.5.1 General . 21
7.5.2 Occupancy . 22

7.5.3 Operating time . 22
7.5.4 Environmental conditions . 22
7.5.5 Cost of electricity . 22
7.6 Impacts on the design of an electrical installation . 22
8 Energy efficiency and load management system . 22
8.1 General . 22
8.2 User specification . 23
8.2.1 General . 23
8.2.2 Requirements on the loads . 23
8.2.3 Requirements on the supplies . 23
8.3 Inputs from loads, sensors and forecasts . 24
8.3.1 General . 24
8.3.2 Communication . 28
8.3.3 Data logging . 29
8.3.4 Loads . 29
8.3.5 Forecasts . 31
8.4 Inputs from the supplies: energy availability and pricing . 31
8.5 Monitoring the performance of the electrical installation . 31
8.6 Management of loads through meshes . 31
8.6.1 General . 31
8.6.2 Electrical energy management system (EEMS) . 31
8.7 Multi-supply source management: grid, local electricity production and
storage . 32
9 Maintenance and enhancement of the performance of the installation . 32
9.1 Methodology . 32
9.2 Installation life cycle methodology . 34
9.3 Energy efficiency life cycle . 34
9.3.1 General . 34
9.3.2 Performance maintenance programme . 34
9.3.3 Verification . 35
9.4 Data management . 35
9.5 Maintenance . 35
10 Parameters for implementation of efficiency measures . 35
10.1 General . 35
10.2 Efficiency measures . 35
10.2.1 Current-using-equipment . 35
10.2.2 Electrical installation . 37
10.2.3 Implementation of management systems . 38
10.2.4 Local power supply . 40
11 Energy efficiency actions . 41
Annex A (informative) Determination of transformer and switchboard location using the
barycentre method . 42
A.1 Barycentre method . 42
A.2 Total load barycentre . 45
A.2.1 General . 45
A.2.2 Sub-distribution board locations . 46
A.2.3 Iterative process . 46
A.3 Method of average route length. 46

– 4 – IEC 60364-8-1:2019 © IEC 2019
Annex B (normative) Method to assess the energy efficiency of an electrical
installation . 49
B.1 General . 49
B.2 Electrical installation efficiency classes . 49
B.3 Determination of the electrical installation efficiency class . 49
B.3.1 General . 49
B.3.2 Industrial, commercial buildings and infrastructures . 50
B.3.3 Residential . 64
Annex C (informative) List of notes concerning certain countries . 70
Bibliography . 71

Figure 1 – Energy efficiency and load management system overview . 23
Figure 2 – Electrical distribution scheme . 26
Figure 3 – Example of measurement equipment selection in an installation . 28
Figure 4 – Iterative process for electrical energy efficiency management . 33
Figure A.1 – Example 1: floor plan of production plant with the planned loads and
calculated barycentre . 44
Figure A.2 – Example 2: barycentre calculated . 45
Figure A.3 – Example of location of the barycentre in an industrial building . 46
Figure A.4 – Example of location of the barycentre using the average route length
method . 48
Figure B.1 – Level of efficiency of the electrical installation efficiency classes . 49

Table 1 – Measurement applications . 25
Table 2 – Overview of the needs for power metering and monitoring . 26
Table 3 – Process for electrical energy efficiency management and responsibilities . 33
Table A.1 – Cable length for supply of DB . 47
Table B.1 – Electrical installation efficiency classes . 50
Table B.2 – Energy efficiency measures . 51
Table B.3 – Determination of energy consumption: coverage . 52
Table B.4 – Main substation: consumption . 52
Table B.5 – Main substation: location. 53
Table B.6 – Voltage drop . 53
Table B.7 – Efficiency of transformer . 54
Table B.8 – Efficiency of fixed installed current using equipment . 55
Table B.9 – Zones . 55
Table B.10 – Usages . 56
Table B.11 – Demand response: coverage . 56
Table B.12 – Demand response: duration . 56
Table B.13 – Meshes . 57
Table B.14 – Measurement by usages . 58
Table B.15 – Occupancy coverage . 58
Table B.16 – Occupancy measurement . 58
Table B.17 – Energy management system (EEMS) . 59
Table B.18 – HVAC control . 59

Table B.19 – Lighting control . 60
Table B.20 – Performance maintenance process . 60
Table B.21 – Frequency of the performance verification process . 60
Table B.22 – Data management . 61
Table B.23 – Working point of transformer . 61
Table B.24 – Presence of continuous monitoring for large energy using systems . 62
Table B.25 – Power factor . 62
Table B.26 – THD . 63
U
Table B.27 – THD . 63
I
Table B.28 – Renewable energy . 64
Table B.29 – Electrical energy storage . 64
Table B.30 – Energy efficiency measures parameters . 65
Table B.31 – Determination of energy consumption . 65
Table B.32 – Zones . 66
Table B.33 – Demand response coverage . 66
Table B.34 – Meshes . 67
Table B.35 – HVAC control . 67
Table B.36 – Lighting control . 68
Table B.37 – Measurement by usage . 68
Table B.38 – Renewable energy . 69
Table B.39 – Electrical energy storage . 69
Table C.1 – Notes concerning certain countries . 70

– 6 – IEC 60364-8-1:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE ELECTRICAL INSTALLATIONS –

Part 8-1: Functional aspects – Energy efficiency

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60364-8-1 has been prepared by IEC technical committee 64:
Electrical installations and protection against electric shock.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) revision of Annex B;
b) revision of 4.2: Energy efficiency assessment for electrical installations;
c) update of 8.3: Input from loads, sensors and forecasts;
d) introduction of new definitions.

The text of this International Standard is based on the following documents:
FDIS Report on voting
64/2353/FDIS 64/2360/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
It has the status of a group energy efficiency publication in accordance with IEC Guide 118
and IEC Guide 119.
The reader's attention is drawn to the fact that Annex C lists all of the "in-some-country"
clauses on differing practices of a less permanent nature relating to the subject of this
document.
A list of all parts in the IEC 60364 series, published under the general title Low-voltage
electrical installations, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.
The contents of the corrigendum of May 2019 have been included in this copy.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 8 – IEC 60364-8-1:2019 © IEC 2019
INTRODUCTION
The optimization of electrical energy usage can be facilitated by appropriate design and
installation considerations. An electrical installation can provide the required level of service
and safety for the lowest electrical consumption. This is considered by designers as a general
requirement of their design procedures in order to establish the best use of electrical energy.
In addition to the many parameters taken into account in the design of electrical installations,
more importance is nowadays focused on reducing losses within the system and its use. The
design of the whole installation has therefore to take into account inputs from users, suppliers
and utilities.
It is important that this document covers existing electrical installations in buildings, in
addition to new installations. It is in the refurbishment of existing buildings that significant
overall improvements in energy efficiency can be achieved.
The optimization of the use of electricity is based on energy efficiency management which is
based on the price of electricity, electrical consumption and real-time adaptation. Efficiency is
checked by measurement during the whole life of the electrical installation. This helps identify
opportunities for any improvements and corrections. Improvements and corrections may be
implemented by redesign or equipment replacement. The aim is to provide a design for an
efficient electrical installation which allows an energy management process to suit the user's
needs, and in accordance with an acceptable investment. This document first introduces the
different measures to ensure an energy efficient installation based on kWh saving. It then
provides guidance on giving priority to the measures depending on the return of investment;
i.e. the saving of electrical energy and reducing of electrical power costs divided by the
amount of investment.
This document is intended to provide requirements and recommendations for the electrical
part of the energy management system addressed by ISO 50001.
It introduces requirements, recommendations and methods for the design and the energy
efficiency assessment of an electrical installation within the framework of an energy efficiency
management approach in order to get the best permanent functionally equivalent service for
the lowest electrical energy consumption and the most acceptable energy availability and
economic balance.
The assessment method described in Annex B based on the electrical energy efficiency of the
installation allows a classification of energy efficiency installation according to the following
levels:
NOTE Account can be taken, if appropriate, of induced works (civil works, compartmentalization) and the
necessity to expect, or not, the modifiability of the installation.
This document introduces requirements and recommendations to design the adequate
installation in order to give the ability to improve the management of the energy performance
of the installation by the tenant/user or for example the energy manager.
All requirements and recommendations of this part of IEC 60364 enhance the requirements
contained in Parts 1 to 7 of the IEC 60364 series.

LOW-VOLTAGE ELECTRICAL INSTALLATIONS –

Part 8-1: Functional aspects – Energy efficiency

1 Scope
This part of IEC 60364 provides additional requirements, measures and recommendations for
the design, erection, operation and verification of all types of low voltage electrical installation
including local production and storage of energy for optimizing the overall efficient use of
electricity.
It introduces requirements, recommendations and methods for the design and the energy
efficiency (EE) assessment of an electrical installation within the framework of an energy
efficiency management approach in order to get the best permanent functionally equivalent
service for the lowest electrical energy consumption and the most acceptable energy
availability and economic balance.
These requirements, recommendations and methods apply, within the scope of
IEC 60364 (all parts), for new installations and modification of existing installations.
This document is applicable to the electrical installation of a building or system and does not
apply to products. The energy efficiency of products and their operational requirements are
covered by the relevant product standards.
Where another standard provides specific requirements for a particular system or installation
application (e.g. manufacturing system covered by ISO 20140 (all parts)), those requirements
may supersede this document.
This document does not specifically address building automation systems.
This group energy efficiency publication is primarily intended to be used as an energy
efficiency standard for the low voltage electrical installations mentioned in Clause 1, but is
also intended to be used by technical committees in the preparation of standards, in
accordance with the principles laid down in IEC Guide 119 and IEC Guide 118.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 61557-12, Electrical safety in low voltage distribution systems up to 1 000 V AC and
1 500 V DC – Equipment for testing, measuring or monitoring of protective measures –
Part 12: Power metering and monitoring devices (PMD)
IEC 61869-2, Instrument transformers – Part 2: Additional requirements for current
transformers
IEC 62053-21, Electricity metering equipment (a.c.) – Particular requirements – Part 21: Static
meters for active energy (classes 1 and 2)

– 10 – IEC 60364-8-1:2019 © IEC 2019
IEC 62053-22, Electricity metering equipment (a.c.) – Particular requirements – Part 22: Static
meters for active energy (classes 0,2 S and 0,5 S)
IEC Guide 118, Inclusion of energy efficiency aspects in electrotechnical publications
IEC Guide 119, Preparation of energy efficiency publications and the use of basic energy
efficiency publications and group energy efficiency publications
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1 General
3.1.1
zone
area (or surface) defining a part of an installation
2 2
Note 1 to entry: Examples of a zone can be a kitchen of 20 m or a storage area of 500 m .
3.1.2
current-using equipment
electric equipment intended to convert electric energy into another form of energy, for
example light, heat, mechanical energy
[SOURCE: IEC 60050-826:2004, 826-16-02]
3.1.3
electrical installation
assembly of associated electric equipment having co-ordinated characteristics to fulfil specific
purposes
[SOURCE: IEC 60050-826:2004, 826-10-01]
3.1.4
usage
type of application for which electricity is used
EXAMPLE Lighting, heating.
3.1.5
load energy profile
figure representing the energy consumption (Y-axis) within a period of time (X-axis) based on
measurements for a mesh or a group of meshes
EXAMPLE Hourly consumption of energy for a period of a week.
3.1.6
power demand profile
figure representing the power demand (Y-axis) for a given integration period within a period of
time (X-axis) based on measurements for a mesh or a group of meshes

3.1.7
electrical energy efficiency
EEE
system approach for optimizing the efficiency of electricity usage
Note 1 to entry: Energy efficiency improvement measures take into account the following considerations:
– both the consumption (kWh) and the price of electricity;
– technology;
– environmental impact.
3.1.8
mesh
one or more circuits of the electrical installation for one or more zones including one or more
services supplying a group of electrical equipment for the purpose of electrical energy
efficiency
3.1.9
active electrical energy efficiency measure
operational measure, either manually or automatically controlled, for optimizing the energy
efficiency of the electrical installation
EXAMPLE Thermostat control, occupancy lighting control, building optimization control systems.
3.1.10
passive electrical energy efficiency measure
measure for optimizing the energy efficiency of the electrical installation by selection and
erection of electrical equipment other than control equipment
EXAMPLE Selection and location of transformer, cross section of cables, routing of wiring system, sub-division of
circuits.
3.1.11
electrical installation efficiency class
defined level of energy efficiency for an electrical installation
Note 1 to entry: See Annex B.
3.1.12
driving parameter
external factors that affect energy efficiency
EXAMPLE Regulation, environmental conditions, occupancy, energy prices and management requirements, mode
of operation, duty cycle, load curves, state, operating, parameters, indoor temperature, lighting levels, production
volume.
3.1.13
barycentre method
procedure to optimize the position of energy source(s) and loads in consideration of energy
efficiency
3.1.14
EE assessment
process to determine the electrical installation efficiency class of an installation
3.2 Electrical energy management
3.2.1
electrical energy management system
EEMS
system monitoring, operating, controlling and managing energy resources and loads of the
installations
– 12 – IEC 60364-8-1:2019 © IEC 2019
3.2.2
load shedding
method(s) of optimizing demand by controlling the electrical loads for variable periods of time
3.2.3
demand response
changes in electric usage by end-user customers from their normal consumption patterns in
response to changes in the price of electricity over time, or to incentive payments designed to
induce lower electricity use at times of high wholesale market prices or when system reliability
is jeopardized
3.2.4
user interface
means that allow the user to monitor and/or control the electrical installation, locally or
remotely
EXAMPLE Visual or audible signal, local display, remote display, push button.
3.3 Energy measurement
3.3.1
measurement
process of obtaining value(s) that can be attributed to a quantity
3.3.2
monitoring
continuing procedure for the collection and assessment of pertinent information, including
measurements, for the purpose of identifying deviations and determining the effectiveness of
the plans and procedures
[SOURCE: IEC 60050-881:1983, 881-16-02, modified – Addition of "identifying deviations
and"; deletion of "for radiation protection".]
3.3.3
power metering and monitoring device
PMD
combination in one or more devices of several functional modules dedicated to metering and
monitoring electrical parameters in energy distribution systems or electrical installations, used
for applications such as energy efficiency, power monitoring and network performance
3.3.4
billing
process that allows energy suppliers or their representatives to invoice their customers
according to a defined contract
Note 1 to entry: These applications can be covered by international standards, regulations such as MID in Europe
or NMI in Australia, and/or utility specifications.
3.3.5
sub-billing
process that allows the property manager to allocate an energy invoice from the energy
supplier and charges as appropriate to specific tenants
3.3.6
cost allocation
process that allows a facility manager to account for energy costs from internal cost centres
that consume energy
EXAMPLE Process line, test and inspection, administration.

3.3.7
estimation
process of judging one or more values that can be attributed to a quantity
Note 1 to entry: Estimation by a competent person can provide data of a reasonable accuracy.
3.3.8
forecast
estimate of the expected value of a parameter at a given future date
3.3.9
total harmonic distortion of the voltage wave
THD
U
ratio of the RMS value of the harmonic content of an alternating quantity (voltage) to the RMS
value of the fundamental component of the quantity (voltage)
3.3.10
total harmonic distortion of the current wave
THD
I
ratio of the RMS value of the harmonic content of an alternating quantity (current) to the RMS
value of the fundamental component of the quantity (current)
3.3.11
degree day
unit used to determine the heating requirements of buildings, representing a fall of one degree
below a specified average outdoor temperature (usually 18 °C) for one day
3.4 Sectors of activities
3.4.1
residential installations
premises designed and constructed for private habitation and including associated areas
Note 1 to entry: Associated areas include common areas, garages, gardens, pools.
3.4.2
commercial installations
premises designed and constructed for commercial operations
EXAMPLE Offices, retail, distribution centres, public buildings, banks, hotels, hospitals, schools.
3.4.3
industrial installations
premises designed and constructed for manufacturing and processing operations
EXAMPLE Factories, workshops.
3.4.4
infrastructure installations
systems or premises designed and constructed for transport or utility operations
EXAMPLE Airport terminals, port facilities, transport facilities.
3.5 Abbreviated terms
BS bonus
DB distribution board
DSO distribution system operator
EEE Electrical energy efficiency

– 14 – IEC 60364-8-1:2019 © IEC 2019
EM energy management
HVAC heating, ventilation and air conditioning
ICT information and communications technologies
KPI key performance indicator
MA performance maintenance
PDS power drive system
PEI peak efficiency index
PM power monitoring
PMD power metering and monitoring device
PV photovoltaic
THD total harmonic distortion
UPS uninterruptible power supplies
4 General
4.1 Fundamental principles
4.1.1 Safety of the electrical installation
The requirements and recommendations of this part of IEC 60364 shall not impair
requirements included in other parts of the IEC 60364 series.
4.1.2 Availability of electrical energy and user decision
Energy efficiency management shall not reduce electrical availability and/or services or
operation below the level desired by the user.
The electrical installation shall have provisions for overriding the energy efficiency
management settings according to the user's decision.
EXAMPLE 1 If someone is ill, the user can decide to heat the room to a higher temperature, even during peak
consumption.
EXAMPLE 2 If a company receives an urgent delivery order, there can be a need for the workshop to operate at
an unexpected hour.
4.1.3 Design principles
The design principles of this document take into account the following aspects:
– load energy profile (active and reactive energy);
– availability of local generation (PV, wind turbine, generator, etc.) and storage;
– reduction of energy losses in the electrical installation;
– the arrangement of the circuits with regard to energy efficiency (meshes, see 7.4);
– the customer's power use distribution over time;
– the tariff structure offered by the supplier of the electrical energy;
maintaining the quality of service and the performance of the electrical installation.
In order to verify the achievement of electrical energy efficiency measures, an overall energy
efficiency assessment should be made.

4.2 Energy efficiency assessment for electrical installations
4.2.1 General
Assessment of installations shall be performed according to Annex B. This assessment shall
be achieved preferably by measurement. It may be also achieved by calculation.
The frequency of periodic inspection of an installat
...