Draft of : 
 
Technical Standard for Prepayment Meter s 
 
 
 
 
Authority for Public Services Regulation  
 
Octo ber 2020  
 
 
 
 
 
     
 ii Technical Standard for Prepayment Meters v  1.2 CONTENTS  
  Page  
1. Introduction  ................................ ................................ ................................ ..........  1 
1.1 Purpose  ................................ ................................ ................................ ...............  1 
1.2 Scope ................................ ................................ ................................ ...................  1 
1.3 Interpretation  ................................ ................................ ................................ ........  1 
1.4 Definitions  ................................ ................................ ................................ ............  2 
2. Metrological Requirements  ................................ ................................ ...................  4 
2.1 Requirement to Use Approved Meters  ................................ ................................ . 4 
3. Compliance with Regulatory Requirements  ................................ ..........................  5 
4. Ownership of Prepayment Meters  ................................ ................................ ........  5 
5. Interface with Prepayment Financial System  ................................ ........................  5 
5.1 General Requirements  ................................ ................................ .........................  5 
5.2 Emergency Credit  ................................ ................................ ................................  7 
5.3 Requirements for Keypad Operated Prepayment Meters  ................................ ..... 7 
5.3.1  General token handling  ................................ ................................ ........................  7 
6. Power Consumption  ................................ ................................ .............................  8 
7. Load Switches and Auxiliary Switches  ................................ ................................ . 8 
7.1.1  General Requirements  ................................ ................................ .........................  8 
7.1.2  Direct Connected Prepayment Meters  ................................ ................................ .. 9 
7.1.3  CT Operated Prepayment Meters  ................................ ................................ ........  9 
7.1.4  Tamper Detection  ................................ ................................ ................................  9    
 iii Technical Standard for Prepayment Meters v  1.2 8. Communica tions  ................................ ................................ ................................ .10 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
     
 1 Technical Standard for Prepayment Meters v  1.2 1. Introduction  
1.1 Purpose  
The purpose of th is Technical Standar d is to establish the additional requirements for 
prepayment metering equipment which may be installed at LV customer  connections between 
networks of all licenced distribution companies and all network user s. 
1.2 Scope  
This Technical Standard applies to Prepayment Metering Equipment owned by the Network 
User  and/or the Distribution Company for the provision of an electricity connection at the 
premises of a Network User and the financial settlement for  electricity transferred . This 
Technical Standard applies to prepayment metering equipment and is in addition to all 
metrological requirements specified for the transfer of electricity from the networks of  Licensed 
Distribution Companies to network users in the Sultanat e of Oman.  
1.3 Interpretation  
In addition 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 stated 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 adv ance 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 da te 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 requiremen t 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 Prepayment Meters v  1.2 1.4 Definitions  
For the purpose of  these Regulations, the following definitions which, where appropriate have 
been taken from the International Electrotechnical Vocabulary as defined in IEC 60050 the 
following definitions which, where appropriate, have been taken from the International 
Electrotechnical Vocabulary as defined in IEC 60050 apply unless an alternative definition has 
been used in the IEC Standards specified in section 2.1.1.2 . In that cas e, the definition used 
in that IEC Standard shall also apply to the relevant section of this  Technical Standard : 
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 Ministry of Commerce, Industry and Investment Promotion  
APSR – means the Authority for Public Services Regulation  
Case  - (of an energy meter) means the set that comprises the base and the cover. [IEV 
314-07-17] 
Cover - (of an energy meter) means  the enclosure on the front of the meter, made either 
wholly of transparent material or of opaque material provided with window(s) through which 
the operation indicator (if fitted) and the display can be read.  [IEV 314 -07-16] 
Current Transformer -  means a n 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]. 
Customer  – means any person, corporate body, or company who has a connection or 
supply agreement with a Distribution Company for the provision of electricity.  
Display - (for static meters) means a device which displays the content(s) of (a) 
memory(ies) . [IEV 314 -07-11] 
Distribution Company  – means an entity holding a licence to distribute and/or supply 
electricity issued pursuant to the Sector Law . 
Maximum Current – means the highest value of current at which a meter meets the 
specified accuracy requirements . [IEV 314 -07-03] 
Meter Type  – means a particular design of meter, manufactured by one manufacturer, 
having:     
 3 Technical Standard for Prepayment Meters v  1.2 a) similar metrological properties;  
b) the same uniform construction of parts determining these properties;  
c) the same ratio of the maximum current to the reference current  
Note 1 – The type may have several values of reference current and reference 
voltage.  
Note 2 – Meters are designated by the manufacturer by one or more groups of 
letters or numbers, or a combination of lett ers and numbers. Each type has one 
designation only.  
Note 3 – The type is represented by the sample meter(s) intended for the type tests 
and whose characteristics (reference current and reference voltage) are chosen 
from the values given in the tables pro posed by the manufacturer. [IEV 314 -07-07] 
Memory  - (for static meters) means the element which stores the digital information 
representing the measured energy. [IEV 314 -07-10] 
Network User – is a generic term that includes customers, generators and other network 
operators using a network of a licenced network operator  
Operation Indicator  - means a device which gives a visible signal of the operation of the 
meter.  [IEV 314 -07-13] 
Rated Current  – means value of current in accordance with which the relevant 
performance of a transformer operated meter is fixed . [IEV 314 -07-02] 
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 b oth 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]    
 4 Technical Standard for Prepayment Meters v  1.2 Year  – means a calendar year according to the Gregorian calendar.  
2. Metr ological  Requirements  
2.1 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 shall be installed at any network connection point in 
Oman. It is not permitted to install meters and, where appropriate, metering 
equipment which otherwise meets the requirements of this or other technical 
standard s but has not been appro ved by MoCI IP.  
2.1.1.2  Meters and metering equipment shall, where appropriate, meet the requirements 
of the following international standards except where varied by this technical 
standard:   
a) IEC 62052 -11 – Electricity metering equipment (AC) – General requiremen ts, 
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 62055 -31 – Electricity metering – Payment systems – Part 31: Particular 
requirements – Static payment meters for active energy (classes 1 and 2)  
f) IEC 61869 -1 - Instrument transformers - Part 1: General requirements;  
g) IEC 61869 -2 - Instrument transformers - Part 2: Additio nal requirements for 
current transformers;  
h) IEC 61869 -3 - Instrument transformers - Part 3: Additional requirements for 
inductive voltage transformers  
i) IEC 61869 -4 - Instrument transformers - Part 4: Additional requirements for 
combined transformers; and  
j) IEC 61869 -5 - Instrument transformers - Part 5: Additional requirements for 
capacitor voltage transformers.  
2.1.1.3  All metering equipment shall be suitable for operation in the electrical system and 
environmental conditions specified in OES 11: General Specificati on for Electrical 
Materials and Equipment, except as modified by this or any other relevant technical 
standard.     
 5 Technical Standard for Prepayment Meters v  1.2 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 throughou t the 
manufacturing period.  
2.1.1.5  In addition to meeting the requirements of this technical standard, meters shall also 
comply fully with the requirements of the Technical Standard for Metering Systems 
and be installed, operated and maintained in accordance wit h the requirements of 
the Regulation for Installation and Maintenance of Metering Systems . 
3. Compliance with Regulatory Requirements  
3.1.1.1  All prepayment meters shall be capable of installation, operation maintenance and 
replacement i n accordance with the Supplier ’s or Distribution Network Operator’s 
Late Payment Code of Practice (as appropriate) . 
3.1.1.2  All prepayment meters shall be capable of meeting the requirements of the 
permitted tariff (as defined by the Sector Law) that is applied at the premise at which 
the mete r is installed.  
4. Ownership of Prepayment Meters  
4.1.1.1  Prepayment meters installed on consumers’ premises in Oman shall be provided 
by the licenced distribut ion network operator . Where an installed prepayment meter 
is not already the responsibility of the relevant network operator, responsibility for 
its ongoing maintenance as a metrological device and as a payment mechanism 
shall be assumed by the relevant network operator.   
5. Interface with Prepayment Financial System  
5.1 General Requirements  
5.1.1.1  Prepayment meters installed on consumers’ premises must be compatible with the 
financial transaction  system established by the licen sed distribution network 
operator  who will specify the type of token that the meter must be able to accept  in 
a Code of Pract ice describing its pre -payment meter services, made available to all 
users of pre -payment meters  and approved by the Authority for Electricity 
Regulation, Oman.   In this context, a token includes the provision by any means of 
a code to be entered using a k eypad associated with  the prepayment meter  and 
also an electronic signal sent to the prepayment meter by a remote device .  
5.1.1.2  Where a virtual token is sent directly from the financial transaction system to the 
meter via a communications channel, the meter mus t be capable of informing the    
 6 Technical Standard for Prepayment Meters v  1.2 financial transaction system that the purchase of another token will soon be 
required.  
5.1.1.3  Where a virtual token is sent directly from the financial transaction system to the 
meter via a communications channel to a meter whose loa d 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.  
5.1.1.4  Prepayment meter s shall be compatible with the Standard Transfer Specification  
and capable of operating in the STS consumption (kWh) and STS monetary 
currency unit modes as set by the licenced distribution network operator  and 
implemented in such a manner that the security of the system at least matche s the  
requirements for the use of a cryptographic algorithm using a 128 -bit DecoderKey 
outlined for the use of the Standard Transfer Specification supported by IEC 62055 -
41:2018 . When operating in monetary currency mode, the currency shown shall be 
Omani R ials and Baisas.  
5.1.1.5  When operating in either consumption or monetary currency mode, the meter shall 
be capable of operating a monthly based step  (or block) tariff.   
5.1.1.6  When operating in either consumption or monetary currency mode, the meter shall 
be capable of operating a tariff that includes a daily standing charge. It shall be 
possible for this charge to be set to zero.  
5.1.1.7  Where a prepayment meter incorporates a specific debt collection facility, debt 
collection shall cease when the agreed debt amount has been de ducted from the 
available credit.  
5.1.1.8  Meters shall show energy consumed as one of the register displays. When 
operating in consumption mode it shall also show kWh credit remaining and, when 
operating in the monetary currency mode it shall also show financial c redit 
remaining.    
5.1.1.9  Meters shall be capable of holding a minimum of  two complete tariff programs with 
individual start dates. A tariff change shall be implemented automatically on the 
start date with the tariff program that is not in use being available to be overwritten. 
The tariff program that is in use shall be overwrite protected.  
5.1.1.10  Where a tariff update  is sent directly from the financial transaction system to the 
meter via a communications channel, the meter must be capable of informing the    
 7 Technical Standard for Prepayment Meters v  1.2 financial tr ansaction system that  the tariff has been updated and shall, without 
prompting, send an information message confirming the tariff in use and the 
updated tariff with their  start date s. The unprompted confirmation shall be sent [24] 
hours following receipt o f the tariff update message.  
5.2 Emergency Credit  
5.2.1.1  On expiry of all prepaid credit, the meter shall operate according to a preprogramed 
emergency credit regime until a credit token is next applied to the meter.  
5.2.1.2  Emergency credit shall be made available consistent with the Supply Terms for pre -
payment meters approved by the Authority for Electricity Regulation, Oman and 
described in a Code of Practice relating to pre -payment meter services prepared 
by the licenced distribution network operator and approve d by the Authority for 
Electricity Regulation, Oman. This Code of Practice  may specify times when 
emergency credit is to be made available and times when it is not. They may also 
include different requirements for the application of emergency credit to vul nerable 
customers that are different from those generally applied . 
5.2.1.3  When emergency credit is used in accordance with the appropriate Code of 
Practice , the load switch shall open and it shall not be possible for it to be closed 
until after additional credit is applied.  
5.2.1.4  When a credit token is applied to a prepayment meter from which emergency credit 
has been utilised, the credit shall be first used to repay the emergency credit facility 
and restore its availability.  
5.3 Requirements for Keypad Operated Prepayment  Meters   
5.3.1  General token handling  
5.3.1.1  During input the numbers entered shall be shown on the meter display , scrolling 
from right to left, with such spaces or other symbol as shown on the paper or 
electronic message provided to the customer added automatically.  
5.3.1.2  The maximum delay for accepting the input of the next digit shall be  20 seconds. 
After that time the display shall return to the default display and the token entry 
aborted without changing the validity status of the token . 
5.3.1.3  After token input the display shall show the status of the token entry  by displaying 
a message within the capability of the display for between 3 and 5 seconds showing 
that the token :    
 8 Technical Standard for Prepayment Meters v  1.2 a) Has been acce pted and its validity cancelled;  
b) Has been rejected with its validity unchanged;  
c) Has already been used;  
d) Is too old to be able to be validated;  
e) Has not been successfully added to the meter because it would breach the 
credit limit of the meter. In this case, the validity of the token must be 
unchanged.  
5.3.1.4  Where a token is rejected, a delay before a reinput should be introduced after the 
third attempt. The period of the delay should increase on each further failed attempt 
until a delay period of up to 25 minutes is reached. The delay period shall be reset 
once a quiescent time of 50 minutes has elapse d. 
5.3.1.5  When a token is accepted, the exact amount of credit shall be added to the 
appropriate register(s) of the prepayment meter . In all other circumstances no 
change shall be made to any of the settings or data of the meter.  
6. Power Consumption  
6.1.1.1  Maximum power consumption of prepayment meters shall be 3 W and 10 VA . The 
power source shall be the voltage circuit on the network side of the metering 
element.  When a polyphase meter is operated on only one or two phases, the total 
consumption of the meter in each of those phases shall not exceed these same 
amounts.  
6.1.1.2  Short -term increases in consumption due to the reading/writing of a token or the 
operation of a contactor are permitted. Where the meter is fitted with a token carrier 
acceptor and the token carrier can be retained in the payment meter, then the power 
consumption requirements shown in section 6.1.1.1  shall also be met with a normal 
token carrier retained in the meter  in quiescent operation.  
7. Load Switch es and Auxiliary Switches   
7.1.1  General Requirements  
7.1.1.1  Prepayment meters shall have a minimum of two auxiliary switches that comply 
with the requirements of IEC 62055 -31 and mirror the operation of the load switch.     
 9 Technical Standard for Prepayment Meters v  1.2 7.1.1.2  The meter shall display the status of the load switch (and/or auxiliary switches) and 
record the number of openings in a billing period and the time and duration of each 
opening. Where m eters provide data to the financial system via a c ommunicat ions 
channel this inf ormation shall also b e transferred.   
7.1.2  Direct Connected Prepayment Meters   
7.1.2.1  Load switches that are part of direct connected prepayment meters shall comply 
with the requirements of IEC 62055 -31. The utilisation category shall be indelibly 
marked 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.  
7.1.3  CT Operated Prepayment Meters  
7.1.3.1  The c ustomer  shall provi de an appropriate load switch operated by a signal within 
the operating capability of the auxiliary switch es and capable of meeting the load 
breaking and fault making requirements of the location at which it is installed.  
7.1.3.2  An appropriate load switch shall m eet the performance requirements for load 
switches contained in the same case as a prepayment 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 installed.  
7.1.3.3  The load switch shall be constructed such that it cannot be dismantled without the 
breaking of a seal applied by the distribution company.  
7.1.3.4  All terminations of the control and load circuitry associated with the load switch shall 
be protected by terminal covers of a type that can be sealed by the distribution 
company.   
7.1.4  Tamper Detection  
7.1.4.1  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 prepayment financial s ystem, 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.  
7.1.4.2  Where a load swi tch 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    
 10 Technical Standard for Prepayment Meters v  1.2 permits access to param eters and settings or a separate password specifically 
allocated to control of the load switch as determined by the distribution company.  
8. Communications  
8.1.1.1  In addition to the requirements of the Technical Standard for Metering Systems the 
prepayment function ality shall be locally available using the specified 
communications interfaces  with the same protection requirements that apply to 
other metrology parameter settings .  
8.1.1.2  Where in house units are employed to provide information to a consumer or to allow 
the input of information to manage a prepayment arrangement, the communications 
system employed shall be designed and operated to ensure 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.  
8.1.1.3  The meter shall only provide the scheduled information to the in -house unit. The 
meter shall only accept requests for the scheduled information and information 
required to man age the prepayment arrangement. Except for entering credit tokens 
in the in house unit that has the effect of providing credit to the prepayment meter, 
it shall not be possible to program either the in -house unit or the meter parameters 
using the communica tions link between them.  
8.1.1.4  Where the meter provides signals that are intended to operate devices via the IoT, 
these signals shall be communicated via the In -House Unit which shall operate as 
a communications hub. The communications link between the meter an d the In -
House Unit shall meet the requirements specified in section 8.1.1.2 .  
8.1.1.5  Where a virtual token and/or tariff update message is sent directly from the financi al 
transaction system to the meter via a communications channel , communication 
between the meter and the financial transaction system shall, in addition to the 
permitted communication between AMR Systems and meters with load switches as 
specified in the Te chnical Standard for Metering Systems,  be limited to:  
a) Amendment of tariff parameters as established in section 5.1.1.9 ;  
b) Acceptance and application of an electronic token ; 
c) Token purchase information as established in section 5.1.1.2 ; and  
d) Confirmation of tariff update as established in section  5.1.1.10 .    
 11 Technical Standard for Prepayment Meters v  1.2 8.1.1.6  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 financial transaction system .  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
[End of Document]