Draft of : 
 
Technical Standard for Metering Systems  
 
 
 
 
Authority for Public Services Regulation  
 
October  2020  
 
 
 
 
 
     
 ii Technical Standard for Metering Systems v 1. 1 CONTENTS  
  Page  
1. Introduction  ................................ ................................ ................................ ..........  1 
1.1 Purpose  ................................ ................................ ................................ ...............  1 
1.2 Scope ................................ ................................ ................................ ...................  1 
1.3 Interpretation  ................................ ................................ ................................ ........  1 
1.4 Definitions  ................................ ................................ ................................ ............  2 
2. Meter Technical Requirements  ................................ ................................ ............  3 
2.1 Application of meters  ................................ ................................ ............................  3 
2.1.1  Requirement to Use Approved Meters  ................................ ................................ . 3 
2.1.2  Meter Accuracy  ................................ ................................ ................................ .... 5 
2.2 Operating Conditions  ................................ ................................ ...........................  5 
2.3 Meter Markings and Information Requirements  ................................ ....................  7 
2.4 Registers and Displays  ................................ ................................ ........................  8 
2.5 Environmental Conditions  ................................ ................................ ....................  9 
2.5.1  Operating Temperature and Humidity  ................................ ................................ .. 9 
2.5.2  Protection against Penetration of Dust and Water  ................................ ............... 10 
2.6 Access to Settings and other Parameters  ................................ ........................... 10 
2.6.2  Form of Crimped Calibration Seal  ................................ ................................ .......10 
2.7 Terminations  ................................ ................................ ................................ .......10 
2.7.2  Form  of Termination Seal  ................................ ................................ .................... 11 
2.7.3  Required Record  ................................ ................................ ................................ .11    
 iii Technical Standard for Metering Systems v 1. 1 2.8 Communications  ................................ ................................ ................................ .11 
2.8.1  Communications Requirements  ................................ ................................ .......... 11 
2.8.2  Permitted Communications with AMR System  ................................ .................... 12 
2.8.3  Communications Module Location  ................................ ................................ ......13 
2.8.4  Communication with In -House Units  ................................ ................................ ...13 
2.9 Alarms and Indications  ................................ ................................ ........................ 14 
3. Load Switches and Auxiliary Switches  ................................ ................................ 14 
3.1.1  General Requirements  ................................ ................................ ........................ 14 
3.1.2  Direct Connected Meters ................................ ................................ ..................... 15 
3.1.3  CT Operated Meters  ................................ ................................ ........................... 15 
3.1.4  Tamper Detection  ................................ ................................ ............................... 15 
4. Power Quality measurements  ................................ ................................ ............. 16 
 
 
  
     
 1 Technical Standard for Metering Systems v 1. 1 1. Introduction  
1.1 Purpose  
The purpose of th is Technical Standard is to establish the requirements for metering 
equipment which shall be installed at all connections between networks of all licenced 
distribution companies and all network user s. 
1.2 Scope  
This Technical Standard applies  to all Metering Equipment owned by the Network User  and/or 
the Network Operator  for the provision of an electricity connection at the premises of a Network 
User and the financial settlement for  electricity transferred . Where appropriate, it shall also 
apply to the transfer of electrical energy generated by the Network User  and supplied to the 
network of the Network Operator . 
This Technical Standard  applies to all connections made to the networks owned or operated 
by all Licensed Network Operators in the Sultanate of Oman.  
1.3 Interpretation  
In addit ion to special meanings contained in the Definitions that follow , within this document:  
• References to the masculine shall include the feminine and references in the 
singular shall include references in the plural and vice versa,  
• Except where explicitly sta ted otherwise all references to section shall be a 
reference to a section in this document , 
• All clock times or other references to time, shall refer to the standard time in the 
Sultanate of Oman , which is four hours in advance of Universal Time Co -ordinated 
(UTC),  
• Any reference to a law or regulation shall be a reference to that law or regulation 
applicable in the Sultanate of Oman  or, following the replacement of that law or 
regulation the new law or regulation from  the date it comes into force , 
• Any general reference to a standard shall be a reference to the current version of 
that standard from its date of implementation . A reference to a particular 
requirement in a standard shall be a specific reference to that req uirement in the 
referenced version of the standard unless a later version of the standard has an 
equivalent requirement in which case it shall be a reference to that equivalent 
requirement in the current version of the standard.  
    
 2 Technical Standard for Metering Systems v 1. 1 1.4 Definitions  
The following  definitions  have , where appropriate , been taken from the International 
Electrotechnical Vocabulary as defined in IEC 60050 : 
Sector Law  - means Royal Decree 78/2004 as amended by Royal Dec ree 59/2009, Royal 
Decree 47/2013  and 78/2020.  
MoCIIP -  means the M inistry of Commerce, Industry and Investment Promotion  
APSR – means the Authority for Public Services Regulation  
Basic Current – means the value of current in accordance with which the relevant 
performance of a direct connected meter is fixed . [IEV 314 -07-06] 
Check Meter  – means a meter of the same class as the Main Meter but its function is to 
support the Main Meter readings in the event of its failure or large errors exceeding the 
limits specified.  
Current Transformer – means an instrument transformer in which the secondary current, 
in normal conditions of use, is substantially proportional to the primary current and differs 
in phase from it by an angle which is approximately zero for an appropriate direction of the 
connections  [IEV 321-02-01] 
Display - (for static meters) means a device which displays the content(s) of (a) 
memory(ies) . [IEV 314 -07-11] 
Interval Data  – meter data collected at defined intervals  for energy settlement or billing 
purposes . 
Main Meter  – means the primary Meter used for billing pu rposes . 
Maximum Current – means the highest value of current at which a meter meets the 
specified accuracy requirements  as specified by the manufacturer .  
Memory  - (for static meters) means the element which stores the digital information 
representing the measured energy. [IEV 314 -07-10] 
Network operator  – means an entity holding a licence to transmit and/or distribute 
electricity issued pursuant to the Sector Law       
 3 Technical Standard for Metering Systems v 1. 1 Network User – is a generic term that includes customers, generators and other network 
operators using a network of a licenced network operator . 
OES  – Oman Electricity Standard  
Rated Current  – means value of current in accordance with which the relevant  
performance of a transformer operated meter is fixed . [IEV 314 -07-02] 
Reference Frequency  – means the value of the frequency in accordance with which the 
relevant performance of a meter is fixed . [IEV 314 -07-05] 
Reference Voltage  – means the value of the voltage in accordance with which the relevant 
performance of a meter is fixed . [IEV 314 -07-04] 
Register - means an electromechanical or electronic device which stores and displays the 
information representing the measured energy  
Note 1 – In static meters,  the register comprises both memory and display.  
Note 2 – A single display may be used with multiple electronic memories to form 
multiple registers.   [IEV 314 -07-09] 
Terminal Block  – means the support made of insulating material on which all or some of 
the terminals of the meter are grouped together. [IEV 314 -07-18] 
Terminal Cover – means the cover which protects the meter terminals and, generally, the 
ends of the external wires or cables connected to the terminals  [IEV 314 -07-19] 
Year  – means a calendar year according to the Gregorian calendar.  
 
2. Meter Technical Requirements  
2.1 Application of meters  
2.1.1  Requirement to Use Approved Meters  
2.1.1.1  Only meters and, where appropriate, metering equipment that has been approved 
by MoCI IP for use in Oman sh all be installed at any network connection point in 
Oman. In addition, all meters a nd, where appropriate, metering equipment shall 
meet the requirements of this technical standard.     
 4 Technical Standard for Metering Systems v 1. 1 2.1.1.2  Meters and metering equipment shall, where appropriate, meet the requireme nts 
of the following international standards except where varied by this technical 
standard:   
a) IEC 62052 -11 – Electricity metering equipment (AC) – General requirements, 
tests and test conditions - Part 11: Metering equipment;  
b) IEC 62053 -21 - Electricity metering equipment (AC) - Particular requirements - 
Part 21: Static meters for active energy (classes 1 and 2);  
c) IEC 62053 -23 - Electricity metering equipment (AC) - Particular requirements - 
Part 23: Static meters for reactive energy (classes 2 and 3);  
d) IEC 62052 -31 - Electricity metering equipment (AC) - General requirements, 
tests and test conditions - Part 31: Product safety requirements and tests;   
e) IEC 61869 -1 - Instrument transformers - Part 1: General requirements;  
f) IEC 61869 -2 - Instrument transformer s - Part 2: Additional requirements for 
current transformers;  
g) IEC 61869 -3 - Instrument transformers - Part 3: Additional requirements for 
inductive voltage transformers  
h) IEC 61869 -4 - Instrument transformers - Part 4: Additional requirements for 
combined t ransformers;  
i) IEC 61869 -5 - Instrument transformers - Part 5: Additional requirements for 
capacitor voltage transformers ; and 
j) IEC 62055 -31 – Electricity metering – Payment systems – Part 31: Particular 
requirements – Static payment meters for active energy  (classes 1 and 2) . 
2.1.1.3  All metering equipment shall be suitable for operation in the electrical system and 
environmental conditions specified in OES 11: General Specification for Electrical 
Materials and Equipment , except as modified by this technical standar d. 
2.1.1.4  The manufacturer of all meters connected to the network of a licenced network 
operator shall hold a valid accreditation under ISO 9001 throughout the 
manufacturing period . 
2.1.1.5  All meter  types that are considered for purchase and installation  are required to 
have successfully passed an assessment of reliability according to an 
internationally recognised procedure that indicates the meter type  should have a 
minimum accurate life of at least 15 years.   
2.1.1.6  In addition to meeting the requirements of this technical standard, meters shall be 
installed, operated and maintained in accordance with the requirements of the 
Regulation for Installation and Maintenance of Metering Systems     
 5 Technical Standard for Metering Systems v 1. 1 2.1.2  Meter Accuracy  
2.1.2.1  The accuracy  class for installed meters  shall be  as shown in Table 1. 
Table 1 - Accuracy classes for meters  
Connection Capacity  Meter active energy 
accuracy class  Reactive energy 
accuracy class  
≤ 1MVA  2 2 
> 1MVA - 20 MVA  1 2 
> 20 MVA – 100 MVA  0.5S 2 
> 100 MVA  0.2S 2 
 
2.1.2.2  In all cases where class 0.2S and 0.5S  meters are required, main and check meters 
shall be provided with separate CT and VT secondary windings. Both main and 
check meters shall record the same active power and energy quantities. Where four 
quadrant metering is required, it will be permitted th at the main and check meters 
record reactive power and energy flows in opposite directions. Where practicable, 
to reduce the risk of common mode failure, main and check meters shall be of 
different manufacture and type.  
2.2 Operating Conditions  
2.2.1.1  Rated operatin g conditions for all meters shall be as shown in Table 2. 
Table 2 - Rated operating conditions  
Meter type  Condition  Value or Range  
Direct Connected 
meters  Unom 415/240 V   
Operating voltage range U 415/240 V   
-20% to +15%  
ƒnom 50 Hz  
Operating frequency range  f 50 H z ± 5% 
Ib 20 A 
Imax 100 A     
 6 Technical Standard for Metering Systems v 1. 1 Meter type  Condition  Value or Range  
Connection Mode – single phase  2 wire, 1 element  
Connection Mode – three phase  4 wire, 3 element  
CT Operated Meters  Unom 415/240 V  
Operating voltage range U 415/240 V   
-20% to +15%  
ƒnom 50 Hz  
Operating frequency range  f 50 H z ± 5% 
In 5 A 
Imax 10 A 
Connection Mode  4 wire, 3 element  
HV Metering  Unom 110 V  
Operating voltage range U 110 V  
-20% to +15%  
ƒnom 50 Hz  
Operating frequency range  f 50 H z ± 5% 
In 1 A 
Imax 6 A 
Connection Mode  3 wire, 2 element  
    
Note: All voltages ≥ 1 kV are considered to be HV.  
2.2.1.2  Meters shall continue to function where:  
a) One or more of the phases are missing, accurately measuring the energy flows 
in the remaining phases;  
b) In the case of a 4 wire, 3 element meter, accurately measuring energy where 
the neutral is missing . 
2.2.1.3  Electronic components shall be protected against overvoltages and voltage spikes  
using a system that does not require the replacement of any surge arresting 
component following its operation.     
 7 Technical Standard for Metering Systems v 1. 1 2.3 Meter Markings  and Information Requirements  
2.3.1.1  The meter manufacturer or supplier shall comply with the information requirements 
of section 5.12 of IEC 62052 -11 and section 5 of IEC 62052 -31 with the 
clarifications stated in this section 2.3 regarding markings and information  declared 
optional in section 5 of IEC 62052 -31. 
2.3.1.2  The designation of function shall be included on packaging, and all manuals and 
shall also be included on either the case marking or the display.  
2.3.1.3  The meter serial number shall be marked on the packaging label.  
2.3.1.4  Environmental condi tions for storage shall be included on the packaging.  
2.3.1.5  Full environmental conditions during operation shall be detailed in the installation 
manual and the maintenance manual.  
2.3.1.6  The IP rating shall be shown on the meter case.  
2.3.1.7  Handling and mounting information shall be included in the installation manual and 
with the packaging.  
2.3.1.8  The case and display markings shall be indelible, distinct and legible from outside 
the meter. Symbols shall be at least 2.75 mm high. Text shall be at least 1.5 mm 
high and contrast in c olour with the background [with a preference for black lettering 
on a white background].  
2.3.1.9  The markings of meters intended for outdoor locations shall withstand solar 
radiation. Multiple values of Unom and ƒnom may be marked if so specified by the 
manufactu rer and an appropriate conformity assessment certificate has been 
obtained.  
2.3.1.10  The serial number shall be provided in a position where it is not readily 
disassociated from parts determining the metrological characteristics.  
2.3.1.11  The language for all text included  in meter case and display markings shall be 
English with all hazard warning details repeated in Arabic. Manuals shall be written 
in English.  
2.3.1.12  The name of the meter owner may be included  as a meter case marking.     
 8 Technical Standard for Metering Systems v 1. 1 2.4 Registers and Displays  
2.4.1.1  Values stored in all registers shall be maintained for a minimum period of 4500 
hours  before being overwritten. Values shall be overwritten on a FIFO basis. In all 
cases, the summation of interval data shall equal the advance in the cumulative 
register value over the same perio d. To ensure that these requirements are 
achieved, meter displays shall be specified to have the number of digits specified 
in Table 3. 
Table 3 - Meter display formats  
Meter type  Display format  
Single phase, direct connected  Minimum 6 digits plus 1 decimal  
Three phase, direct connected  Minimum 7 digits plus 1 decimal  
LV CT Operated  Minimum 7 digits plus 1 decimal  
HV CT Operated  Minimum 8 digits configured to match 
load flows.  
 
2.4.1.2  All meters shall be capable of measuring and storing all data required for billing and 
financial settlement. As a minimum, the following values shall be available:  
a) In the case of class  0.5S, 1 and 2 meters:  
 Total cumulative active energy in kWh or  in MWh;  
 Cumulative kWh (or MWh) per billing period;  
 Active energy by Time of Use with a minimum of four programmable 
registers;  
 Active energy by Demand Period;  
 Maximum demand of active energy by Billing Period;  
 Maximum de mand of active energy by Time of Use;  
 Reactive energy by Demand Period  
 total cumulative reactive energy in kvarh.  
b) In the case of class 0.2S  meters:  
 Total cumulative active energy in MWh;  
 Cumulative active energy per billing period;  
 Active energy by Demand  Period ; 
 Maximum demand of active energy by Billing Period;  
 Total cumulative reactive energy;  
 Reactive energy by Demand Period .    
 9 Technical Standard for Metering Systems v 1. 1 2.4.1.3  Where required, meters shall record active and reactive energy separately in each 
direction of flow.  
2.4.1.4  In the case of electronic r egisters, the minimum retention time for results is ten 
years for a disconnected meter. Electronic indicating devices shall be provided with 
a display test that switches all the display segments on then off for the purpose of 
determining whether all displa y segments are working.  
2.4.1.5  Where meters are accessible, the register being displayed shall be scrolled using 
a push -button using a sequence that allows access to all registers. It shall be 
possible to programme the display to show any register as the default register.  
2.4.1.6  Where a meter  is not accessible, it shall have an automatic sequencing display  with 
a display period of 5 seconds for each register .  
2.4.1.7  The display shall show the existence of any alarm condition which, in the case of 
an accessible meter shall be i nterrogated by using a push -button. In the case of a 
meter which is not accessible, the nature of the alarm shall also be displayed except 
for the tamper alarm where only the existence of an alarm condition shall be 
displayed.   
2.4.1.8  The duration of each Demand  Period shall be within ± 0.1%, except where time 
synchronisation has occurred in a Demand Period . It shall be possible to set 
Demand Periods of : 
 30 and 60 minutes in the case of single phase direct connected meters;  
 5, 10, 15, 30 and 60 minutes in the case of all other  meters .  
2.4.1.9  The start and end time of billing periods shall be programmable.  
2.5 Environmental Conditions  
2.5.1  Operating Temperature and Humidity  
2.5.1.1  Meter shall operate within the temperature range:  
 Minimum temperatu re - 0 oC 
 Maximum temperature - 60 oC 
 Maximum mean temperature over 24 hours - 50 oC 
 Mean temperature over 1 year - 35 oC    
 10 Technical Standard for Metering Systems v 1. 1 2.5.1.2  Meter shall operate within the humidity range:  
 Minimum relative humidity – 0% 
 Maximum relative humidity – 100%  
2.5.2  Protection against Penetration of Dust and Water   
2.5.2.1  The minimum IP rating as defined in IEC 60529 shall be IP 54 for metering 
equipment mounted in enclosed locations (including locked meter cabinets) and IP 
55 for equipment mounted externally.  
2.6 Access to Settings and other Para meters  
2.6.1.1  It shall not be possible to locally upgrade non -legally relevant software, change 
settings or modify any relevant parameters without first breaking a seal that is not 
a calibration seal.  
2.6.1.2  For meters that are remotely read, it shall be possible to r emotely change settings 
and parameters only following the entry of a higher -level password than that used 
to control data collection.  
2.6.1.3  For meters that are remotely read, it shall be possible to remotely upgrade non -
legally relevant software only following the entry of a higher -level password than 
that used to remotely change settings and parameters.  
2.6.1.4  Details of all changes to settings or parameters shall be retained in an event record 
that shall have the capacity to retain 100 parameter setting change event s. Details 
of software upgrades shall be retained in a separate event log.  
2.6.2  Form of Crimped Calibration Seal  
2.6.2.1  A calibration seal shall be comprised of two parts – a piece of wire rope 150 mm 
long with a minimum diameter of 0.9mm and a sealing ferrule - which, when fitted 
together and compressed by a sealing tool, will prevent the removal of a seal 
without clear evidence of that removal.  
2.6.2.2  The full specification for this seal and management of sealing tools shall be as 
determined by  MoCI IP. 
2.7 Terminations  
2.7.1.1  The terminal block shall cater for a conductor size of 35 mm2 for direct connected 
meters.     
 11 Technical Standard for Metering Systems v 1. 1 2.7.1.2  The terminal block shall cater for a wiring size of 6 mm2 for CT operated meters 
and CT/VT operated meters.   
2.7.1.3  All terminal blocks shall have  covers to which a termination seal can be fitted.  
2.7.2  Form of Termination Seal  
2.7.2.1  Individually numbered, tamper evident security seals as specified and provided by 
the relevant network operator shall be used to seal all terminations. At the discretion 
of the releva nt network operator, these may be indicative seals or barrier seals.  
2.7.3  Required Record  
2.7.3.1  The relevant network operator shall maintain a record of the individual numbered 
seal, its location and the specific equipment to which it is attached. This record shall  
include details of the date and time the seal was applied and by whom.  
2.7.3.2  The relevant network operator shall establish a mechanism to allow any authorised 
party to notify the relevant network operator that a seal has been broken and the 
circumstances. The r elevant network operator shall carry out such investigation as 
it deems appropriate and reseal the installation.  
2.8 Communications  
2.8.1  Communications Requirements  
2.8.1.1  Meters shall be capable of interfacing with third party AMR systems . To achieve 
this: 
 Meters shall  use a protocol that allows it to be automatically detected when 
connected to a communications bus using e.g. the DLMS/COSEM  protocol to 
IEC 62056 Parts 1 to 9 , Euridis  bus to IEC 62056 -3-1, or similar proprietary 
protocol.  
 All protocols employed shall use  an open system architecture based on publicly 
available international standards, and be freely available to any third party for 
integrating into an AMR/AMI central collection system.  
 The protocol employed shall demonstrate compliance and/or certification  to 
IEC 62056 or other  relevant standards.    
 Meters shall be capable of being multi -dropped onto the same communication 
bus for remote interrogation and programming purposes.     
 12 Technical Standard for Metering Systems v 1. 1  The electrical interface for remote communications shall at minimum comply 
with the RS -485 standard.   
2.8.1.2  It shall be possible to undertake local meter programming and interrogation through 
a separate optical port to IEC 6 2056 – 21 with a magnetic coupler/ring connection. 
This access shall be protected by an appropriate authentication re gime that 
contains at minimum 2 stages. Access via the optical port shall not give access to 
any wider communications system to which the meter is connected.  
2.8.1.3  Meters shall also be capable of connecting directly to a remote communications 
carrier via a suitable communications module to  GSM/GPRS, PLC , PSTN and RF 
carrier systems . Access to the communications module shall not permit the 
transmission of data to the carrier system unless first polled by the remote device . 
2.8.1.4  AMR systems using class 2 meters shall be based on PLC, GPRS or I oT cloud 
based wireless services. The use of private (point -to-point) radios, drive by reading, 
and walk by reading is discouraged, unless necessary to establish GPRS or I oT 
based communications in a specific location due to low signal strength.  The use of 
local data concentrators is permitted only where PLC systems are used.  
2.8.1.5  Communications systems shall be designed and operated to en sure the protection 
of data and meet cyber security requirements specified by APSR  that are no less 
rigorous than would be developed by following the requirements of the ISO/IEC 
27001 suite of standards .  
2.8.2  Permitted Communications with AMR System  
2.8.2.1  Where a me ssage is sent directly from the AMR system to the meter via a 
communications channel , communication between the meter and the AMR system 
shall be limited to:  
a) Communications initiated by the meter without password:  
i. Alarms generated by the meter;  
ii. Provision o f confirmatory messages as per section 2.8.2.3 ; 
b) Communication controlled by Meter Reading Password : 
i. Provision of meter readings;  
ii. Interrogation of a larms generated by  the meter;  
c) Communication controlled by Meter Setting Password : 
i. Provision of details of setting parameters;  
ii. Modification of setting parameters ; 
d) Communication controlled by Load Switching Password :    
 13 Technical Standard for Metering Systems v 1. 1 i. Opening of the Load Switch where fitted ; 
ii. Priming Load Switch for local closing . 
2.8.2.2  Before acknowledging and acting on any such electronic transmission, the 
prepayment meter shall:  
a) Establish that the communication has entered the meter by the expected 
mechanism;  
b) Establish that the necessary identification of the source of the communication 
has been accurately demonstrated;  
c) Establish that the communication is a permitted communication;  
d) Establish that the appropriate password for the instruction type has been 
provided.  
In the event that the communication fails any one of the necessary proofs of 
accuracy, the meter shall not react to the receipt of any such message but shall 
send an alarm to the AMR system.  
2.8.2.3  Where a validated instruction to change meter parameters or to c hange the position 
of a load switch is received by the meter then, without prompting by the AMR 
system, the meter shall transmit a confirmatory message of the receipt of such a 
message 24 hours following its validation. The confirmatory message shall eithe r 
include all relevant details or force the AMR system to initiate an interrogation.  
2.8.3  Communications Module Location  
2.8.3.1  Where provision for a communications module is required, the case should contain 
space for the installation of the specified communication  modules. This space shall 
not conflict with the space intended for other purposes and shall be located either 
under the terminal cover or below a special cover, but not within the area protected 
by the calibration seal. It shall be possible to fit a termi nation seal to this cover.  
2.8.4  Communication with In -House Units  
2.8.4.1  The meter shall be programmed to only provide the scheduled information to the 
in-house unit. The meter shall only accept requests for the scheduled information. 
It shall not be possible to prog ram either the in -house unit or the meter parameters 
using the communications link between them.  
2.8.4.2  Where the meter provides signals that are intended to cause the operat ion of 
customer’s  devices via the IoT, these signals shall be communicated via the In -   
 14 Technical Standard for Metering Systems v 1. 1 House Unit which shall operate as a communications hub. The communications link 
between the meter and the In -House Unit shall meet the requirements specified in 
section 2.8.1.4 . 
2.9 Alarms and Indications  
2.9.1.1  All meters shall maintain an event log of at least 100 events of the following types:  
a) Low Battery ;  
b) Physical tampering attempts;  
c) DC Magnetic induction > 200 mT;  
d) Detected meter error ;  
e) Meter setting changes including changes to parameter settings;  
f) Loss of voltage (by phase) ; 
g) Phase/neutral inversion;  
h) In the case of unidirectional meters – reverse power flows;  
i) In the case of polyphase meters, phase currents in different directions .  
2.9.1.2  All meters shall maintain a separate event log of at least 100 events of the type of 
software upgrade conducted in accordance with the requirements of section 2.6. 
2.9.1.3  In the case of all meters which are remotely read, the meter shall force the delivery 
of all alarm and indication data as part of the first normal reading following 
occurrence and weekly thereafter for as long as the situation continues.  
3. Load Switches and A uxiliary Switches  
3.1.1  General Requirements  
3.1.1.1  Where specified, meters shall have a fault making/load breaking load switch and a 
minimum of two auxiliary switches that comply with the requirements of IEC 62055 -
31 and mirror the operation of the load switch.  
3.1.1.2  It shall be possible for the load switch (and associated auxiliary switches) to be 
controlled by remote signals from the AMR system. Whether this facility is utilised 
shall be one of the parameters available to be set by the distribution company.  
3.1.1.3  Where a close signal  is sent from the AMR  system to a meter whose load switch is 
in the open position, the contactor shall not close until a local action is taken – either 
by pressing a physical pushbutton on the meter or by sending a close signal from 
a local control  unit in the charge of the customer .  
3.1.1.4  The meter shall display the status of the load switch (and auxiliary switches) and 
record the number of openings in a billing period and the time and duration of each    
 15 Technical Standard for Metering Systems v 1. 1 opening. Where meters provide data to the AMR  syste m via a communications 
channel this information shall also be transferred.  
3.1.2  Direct Connected Meters  
3.1.2.1  Load switches that are part of direct connected meters shall comply with the 
requirements of IEC 62055 -31. The utilisation category shall be indelibly mark ed 
on the meter. The person responsible for the installation of a prepayment meter 
shall ensure that meter is capable of meeting the load breaking and fault making 
requirements of the location at which it is installed.  
3.1.3  CT Operated Meters  
3.1.3.1  The customer shall  provide an appropriate load switch operated by a signal within 
the operating capability of the auxiliary switches and capable of meeting the load 
breaking and fault making requirements of the location at which it is installed.  
3.1.3.2  An appropriate load switch s hall meet the performance requirements for load 
switches contained in the same case as a meter as specified in Annex C of IEC 
62055 -31 modified as appropriate for the maximum load current and prospective 
fault current at the location at which it is to be i nstalled.  
3.1.3.3  The load switch shall be constructed such that it cannot be dismantled without the 
breaking of a seal applied by the distribution company.  
3.1.3.4  All terminations of the control and load circuitry associated with the load switch shall 
be protected by te rminal covers of a type that can be sealed by the distribution 
company.  
3.1.4  Tamper Detection  
3.1.4.1  In the event that meter tampering is detected, in addition to the display of an alarm 
condition and the transfer of any alarm sent to the metering management  system, 
the load switch shall open. Where tampering is detected outside normal working 
hours, the distribution company may specify that opening of the load switch will be 
delayed until the start of normal working hours on the following day.  
3.1.4.2  Where a load s witch opens as a result of the detection of an incidence of meter 
tampering, it shall only be possible for the switch to be closed following the entry of 
a password directly at the meter. The password shall either be the password that 
permits access to par ameters and settings or a separate password specifically 
allocated to control of the load switch as determined by the distribution company.     
 16 Technical Standard for Metering Systems v 1. 1 4. Power Quality measurements  
4.1.1.1  Where APSR  so directs, the metering service provider or network operator shall 
ensure tha t the installed meter is capable of measuring, recording and delivering 
power quality measurements by the same mechanism as the meter is read.  
4.1.1.2  Where an installed m eter is capable of providing instantaneous power quality 
measurements, these shall be downloaded at routine meter reading, in the case of 
meters that are read remotely, and, in the case of meters that can only be read 
locally, in the event that any network user connected to the same primary substation 
complains about power quality.   
4.1.1.3  The met er shall be capable of displaying instantaneous values of:  
a) Frequency;  
b) Phase voltage;  
c) Current per phase  
d) Power factor;  
e) V to I phase angle per phase; and  
f) Phase rotation.  
4.1.1.4  Power Quality measurements shall be accurate to within  ± 1%. 
 
[End of Document]