1 
 THE WEIGHTS AND MEASURES (ELECTRICITY METERS) RULES , 2015.  
ARRANGEMENT OF RULES  
PART I—P RELIMINARY Rule  
1.  Title.  
2.  Interpretation.  
PART II—U NITS OF MEASUREMENT AND STANDARDS . 
3.  Units of electrical energy.  
4.  Secondary standards.  
5.  Working standards.  
PART III—M ETROLOGICAL REQUIREMENTS OF METERS  
6.  Rated operating conditions.  
7.  Accuracy requirements.  
8.  Direction of energy flow.  
9.  Maximum permissible error.  
10.  Allowed effects of influence.  
11.  Allowed effects of disturbance.  
12.  Timing requirements for interval and multi-tariff m eters.  
13.  Meter marking.  
Rule  
14.  Protection of metrological properties.  
15.  Software identification.  
16.  Software and parameter protection.  
17.  Separation of electronic devices and sub-assemblies .  
18.  Data quality.  
19.  Data storage.  
20.  Data transmission and internal clocks.  
21.  Checking facility event recorder.  
22.  Display in a meter.  
23.  Test output.  
24.  Durability.  
PART IV—T YPE APPROVAL DOCUMENTATION AND  
IMPORTATION OF METERS  
25.  Meaning of “type”.  
26.  Application for “type” approval.  
27.  Importation of meters.  2 
 PART V—F UNCTIONS OF THE BUREAU . 
28.  Functions of the Bureau.  
PART VI—V ERIFICATION OF METERS  
29.  Inspector to verify meters.  
30.  Meter verification procedures.  
31.  Verification marks.  
32.  Sealing.  
33.  Inspector to apply Verification mark and seal.  
34.  Verification certificate.  
35.  Withdrawal of meter from service.  
PART VII—G ENERAL  
36.  Delivery or sale of meters.  
37.  Offences related to meters.  
SCHEDULES  
Schedule 1—Certificate of verification of working s tandard  
Schedule 2—Metrological requirements;  
Table 1- Rated operating conditions  
Table 2- Base maximum permissible error  
Table 3- Limits of temperature coefficient of error  
Table 4- Limit of error shift due to influence quan tities Table 5- Disturbances  
Schedule 3—Certificate to be issued by Inspector af ter meter verification;  
Schedule 4—Verification Fees   3 
 The Weights and Measures (Electricity Meters) Rules , 2015. 
(Under sections 22 and 43 of the Weights and Measur es Act, Cap.  103)  
IN EXERCISE of the powers conferred on the Minister responsible  for trade by sections 22 and 
43 of the Weights and Measures Act, Cap 103, these Rules are made this 22nd day of May, 
2015. 
PART I—P RELIMINARY 
1.  Title.  
These Rules may be cited as the Weights and Measure s (Electricity Meters) Rules, 2015.  
2.  Interpretation.  
In these Rules, unless the context otherwise requir es— 
“absolute error” means indicated energy value minus  the true energy value; 
“accuracy class” means a class of measuring instrum ents or measuring systems that meet 
stated metrological requirements that are intended to keep measurement errors or 
instrumental uncertainties within specified limits under specified operating 
conditions; 
“Act” means the Weights and Measures Act, Cap. 103;  
“active power” means the rate at which energy is tr ansported measured as the time mean 
of instantaneous power, which is calculated at each  instant as the product of voltage 
and current; 
“Authority” means the Electricity Regulatory Author ity established under the Electricity 
Act, 1999, Cap. 145; 
“auxiliary device” means a device within the meter that is not part of the basic metrology 
function; 
“base maximum permissible error” means the extreme values of the relative error of 
indication of a meter permitted by these Rules, whe n the current and power factor are 
varied within the intervals given by the rated oper ating conditions, and when the 
meter is otherwise operated at reference conditions ,   
“Bureau” means Uganda National Bureau of Standards established under the Uganda 
National Bureau of Standards Act, Cap. 327 ; 
“case” means the case of a meter that completely en closes it; 
“checking facility” means a facility that is incorp orated in the meter and which enables 
faults that would otherwise be significant faults t o be detected and acted upon in such 
a way that incorrect registration is prohibited or recorded separately; 
“consumer” means any person supplied or entitled to  be supplied with electrical energy 
for personal, industrial, commercial use but does n ot include a person supplied with 
electrical energy for delivery to another person; 4 
 “current” means the root mean square value of the e lectrical current flowing through the 
meter; 
“current circuit” includes the internal connections  of the meter and part of the measuring 
element through which flows the current of the circ uit to which the meter is 
connected; 
“current range” means the range of current, over wh ich the meter is designed to function 
within specified error limits; 
“defect” includes a departure of a meter quality ch aracteristic from its intended level of 
state that occurs with a severity sufficient to cau se the meter not to satisfy normal 
usage requirements; 
“direct connected meter” means a meter intended for  use by direct connection to a circuit 
or circuits being measured without the use of exter nal devices such as instrument 
transformers; 
“Director” means the Executive Director of Uganda N ational Bureau of Standards; 
“distributor” means a person who owns, operates, ma nages or controls distribution 
facilities for the movement or delivery of electric ity to consumers; 
“disturbance” means an influence quantity having a value within limits specified in 
accordance with these Rules, but outside the specif ied rated operating conditions of 
the meter; 
“electrical energy” means electrical energy when ge nerated, transmitted, distributed or 
utilised for any purpose except the transmission of  any communication signal; 
“electricity meter” means a de vice that measures t he amount of electric energy consumed 
by a residence business or an electrically powered device; 
“electrical energy meter” has the same meaning as e lectricity meter; 
“electromechanical meter” means a meter in which cu rrents in fixed coils react with the 
currents induced in the conducting moving element, generally a disk or disks which 
cause their movement proportional to the energy to be measured; 
“fault” means the difference between the error of i ndication and the intrinsic error of a 
measuring instrument; 
“frequency” means the frequency of the voltage and current supplied to the meter; 
“harmonic” means a part of a signal that has a freq uency that is an integer number multiple 
of the fundamental frequency of the signal, where t he fundamental frequency is 
generally the nominal frequency; 
“harmonic number” means an integer number used to i dentify a harmonic and is the ratio 
of the frequency of a harmonic to the fundamental f requency of the signal; 
“influence factor” means an influence quantity havi ng a value within the rated operating 
conditions specified in these Rules; “influence qua ntity” means a quantity that is not 
the measure but affects the result of the measureme nt; 5 
 “initial intrinsic error” means the intrinsic error  of a measuring instrument as determined 
prior to performance tests and durability evaluatio ns; 
“inspector” means an Inspector of Weights and Measu res appointed under the Act; 
“interval meter” means an electricity meter which d isplays and stores the result as 
measured in predetermined time intervals; 
“intrinsic error” means the error of a measuring in strument, determined under reference 
conditions;  
“low current” means the lowest value of current wit hin the manufacturer’s specified range 
of current values at and above which the maximum pe rmissible error requirement is 
constant with regard to current variations;  
“maximum current” means the highest value of curren t at which the meter is specified by 
the manufacturer to meet the accuracy requirements of these Rules;  
“maximum permissible error” means the extreme value  of measurement error with respect 
to a known reference quantity value prescribed by t hese Rules for given 
measurement;  
“maximum permissible error shift” means the extreme  values of the relative error of 
indication of a meter permitted by these Rules, whe n a single influence factor is taken 
from its value at reference conditions and varied w ithin the rated operating 
conditions; 
“measuring element” means the part of a meter that transforms a current and voltage into 
a signal proportional to the power or energy; 
“meter constant” means the value expressing the rel ation between the energy registered 
by the meter and the corresponding value of the tes t output; 
“minimum current” means the lowest value of current  at which the meter is specified by 
the manufacturer to meet the accuracy requirements of these Rules; 
“multi-tariff meter or multi-rate meter” means an e lectricity meter intended to measure 
and display electrical energy where energy will hav e more than one tariff rate 
including a tariff rates determined by time, load o r some other quantity;  
“nominal frequency” means the frequency of the volt age and current specified by the 
manufacturer for normal operation of the meter; 
“nominal voltage” means the voltage specified by th e manufacturer for normal operation 
of the meter; 
“place on market” means making a meter available in  Uganda for an end user; 
“power factor” means the ratio of active power to t he apparent power ; 
“primary rated register” means a register where the  scale factor due to the used instrument 
transformer is considered such that the measured en ergy on the primary side of the 
instrument transformer is indicated; 6 
 “put into use” means the first use of a meter inten ded for the end user for the purpose, for 
which it was intended; 
“rated operating conditions” means a set of specifi ed measuring ranges for performance 
characteristics and specified operating ranges for influence quantities, within which 
the variations of operating errors of a meter are s pecified and determined; 
“reference condition” means operating condition pre scribed for evaluating the 
performance of a measuring instrument or measuring system or for comparison of 
results; 
“register” means part of the meter that stores the measured values; 
“register multiplier” means a constant with which t he register reading shall be multiplied 
to obtain the value of the metered energy; 
“relative error” means absolute error divided by th e true energy value, usually expressed 
as a percentage; 
“significant fault” means a fault greater than the value specified in these Rules; 
“starting current” means the lowest value of curren t specified by the manufacturer at which 
the meter should register electrical energy at unit y power factor and, for poly-phase 
meters, with balanced load; 
“static meter” means a meter in which current and v oltage act on solid state electronic 
elements to produce an output proportion to the ene rgy to be measured; 
“test output” means a device which can be used for testing of the meter, providing pulses 
or the means to provide pulses corresponding to the  energy measured by the meter; 
“transformer operated meter” means a meter intended  for use with one or more external 
instrument transformers; 
“transitional current” means the value of current a t and above which the meter is specified 
by the manufacturer to lie within the smallest maxi mum permissible error 
corresponding to the class index of the meter; 
“voltage” means root mean square value of the elect rical voltage supplied to the meter;  
“voltage circuit” includes the internal connections  of the meter, part of the measuring 
element and, in the case of static meters, part of the power supply, supplied with the 
voltage of the circuit to which the meter is connec ted. 
PART II—U NITS OF MEASUREMENT AND STANDARDS 
3.  Units of electrical energy.  
(1)  The units of measurement for the sale of electrical  energy shall 
be— 
(a)  the watt hour; 
(b)  the volt-ampere hour; or  7 
 (c)  the volt ampere reactive (var). 
(2)  Where the unit of measurement for the sale of elect ricity is the volt-ampere hour, 
vector addition shall be used to determine the tota l number of such units in a combination of 
polyphase circuits. 
(3)  The units of measurement for the sale of electricit y shall include multiples and 
submultiples of such units. 
4.  Secondary standards.  
(1)  The Director shall procure and cause to be maintain ed suitable secondary 
standards to which all electrical energy testing me ters shall be traceable. 
(2)  The Director shall cause the secondary standards, f or the time being, to be re-
verified by an electrical laboratory accredited for  such purposes at least once in every fifteen 
years. 
5.  Working standards.  
(1)  The Director shall procure and keep records of work ing standards of electrical 
energy testing meters for the use of inspectors in the exercise of their duties under these Rules. 
(2)  The Director shall maintain working standards for e lectrical energy testing 
meters and shall cause every working standard to be  calibrated at least once every twelve 
months and issue a certificate prescribed in Schedu le 1.  
PART III—M ETROLOGICAL REQUIREMENTS OF METERS 
6.  Rated operating conditions  
(1)  The rated operating conditions set out in Table 1 o f Schedule 2 to these Rules 
shall apply to the meters in the accuracy classes s pecified in rule 7(1) of these Rules. 
(2)  A meter shall not exceed the maximum permissible er ror for the specified class 
under rated operating conditions. 
7.  Accuracy requirements.  
(1)  A meter shall be designed and manufactured so that when exposed to 
disturbances significant faults do not occur. 
(2)  Where the checking facility detects and acts upon a  significant fault, the meter 
shall clearly indicate that such an event has occur red and the fault shall no longer be considered 
a significant fault after that. 
(3)  The manufacturer shall indicate the accuracy class of electrical energy meter  
according to internationally accepted standard. 
8.  Direction of energy flow.  
(1)  The polarity of energy flow shall be defined by the  manufacturer’s connection 
instructions for the meter and shall be capable of bi-directional energy flow. 8 
 (2)  An electrical energy meter shall fall into one of t he following categories— 
(a)  single - register, bi-directional; 
(b)  two - register, bi-directional; 
(c)  single - register, positive direction only; or  
(d)  single - register, uni-directional.  
9.  Maximum permissible errors.  
(1)  The relative error for an electrical energy meter s hall be within the base 
maximum permissible error specified in Table 2 of S chedule 2.  
(2)  An electrical energy meter shall be able to carry t he imax continuously without 
an error larger than the base maximum permissible e rror for a meter of its class.  
(3)  The error shift due to continuous current at imax shall not be larger than fifty 
percent of the base maximum permissible error for t he relevant class.  
10.  Allowed effects of influence.  
(1)  The temperature coefficient of an electrical energy  meter that is operated at 
reference conditions shall fulfill the requirements  prescribed in Table 3 in Schedule 2. 
(2)  The variations of error when the load current and p ower factor are held constant 
at a point within the operating range with the mete r operated at reference conditions, and when 
any single influence quantity is varied from its va lue at reference conditions to its extreme 
values defined in Table 4 of Schedule 2 shall be su ch that the additional percentage error is 
within the corresponding limit of error shift given  in Table 4.  
(3)  An error shift larger than that prescribed in Table  4 in Schedule 2  shall 
constitute a significant fault. 
(4)  An electrical energy meter shall continue to functi on after the completion of 
each of these tests specified under this rule. 
11.  Allowed effects of disturbance.  
(1)  An electrical energy meter shall withstand disturba nce encountered under 
conditions of normal use. 
(2)  Where an electrical energy meter is operated under the conditions set out in 
Table 5 of Schedule 2 and no current is applied, a change in the registers or pulses of  the test 
output shall not be considered as a significant fau lt if the change in the registers or equivalent 
energy of the test output is less than: critical ch ange value= m . U nom .I max . 10-6 Kw. h 
Where m is the number of measuring elements 
12.  Timing requirements for interval and multi-tariff m eters. An interval electrical 
energy meter shall be able to measure and store int erval data for a minimum of thirty five 
days of thirty minute interval data. 
13.  Meter marking.  
(1)  The following information shall be marked on every meter— 9 
 (a)  the name of the manufacturer; 
(b)  the Unom; 
(c)  the Imax; 
(d)  the Itr; 
(e)  the approval mark; 
(f)  the serial number; 
(g)  the number of phases; 
(h)  the number of wires; 
(i)  the register multiplier, if other than unity; 
(j)  the meter constant or constants;  
(k)  the year of manufacture; 
(l)  the class index; 
(m)  the directionality of energy flow, if the meter is bidirectional or unidirectional but no 
marking is required if the meter is capable only of  positive direction energy flow; 
(n)  the meter type; 
(o)  the temperature range; 
(p)  the humidity and water protection information; 
(q)  the impulse voltage protection information; 
(r)  the fnom; 
(s)  the connection mode or modes for which the meter is  
specified; 
(t)  the connection terminals uniquely identified to dis tinguish between one terminal and 
another. 
(2)  The markings of the information specified in subrul e (1) shall be indelible, 
distinct and legible from outside the meter. 
(3)  The markings of meters intended for outdoor locatio ns shall withstand solar 
radiation and multiple values of Unom and fnom   shall be marked, if so specified by the 
manufacturer. 
(4)  Where the serial number of the meter is affixed to dismountable parts, the serial 
number shall be marked in a position where it is no t readily disassociated from parts 
determining the metrological characteristics of the  meter. 
14.  Protection of metrological properties.  10 
 (1)  The metrological properties of every meter shall be  protected. 
(2)  The means to protect the metrological properties of  a meter intended for outdoor 
locations shall withstand solar radiation. 
15.  Software identification.  
(1)  The software of an electrical energy meter shall be  clearly identified with the 
software version or another token. 
(2)  The identification may consist of more than one par t but at least one part shall 
be dedicated to the legal purpose. 
(3)  The identification shall be inextricably linked to the software itself and shall be 
presented on command or displayed during operation.  
(4)  For the purposes of identification under this rule,  an imprint of the software 
identification on the meter shall be an acceptable solution if it satisfies  the following 
conditions— 
(a)  the user interface does not have any control capabi lity to activate the indication of 
the software identification on the display or the d isplay does not technically allow 
the identification of the software to be shown; 
(b)  the meter does not have an interface to communicate  with the software identification; 
and 
(c)  after production of the meter a change of the softw are is not possible or only possible 
if the hardware or a hardware component is also cha nged. 
(5)  It is the responsibility of the manufacturer of the  hardware or hardware 
component to ensure that the software identificatio n is correctly marked on the meter. 
16.  Software and parameter protection.  
(1)  The legally relevant software of a meter shall be s ecured against any 
unauthorised modification, loading or change.  
(2)  Only those functions specified under these Rules sh all be allowed to be activated 
by the user interface and the activation shall be d one in such a way that it does not facilitate 
fraudulent use. 
(3)  The parameters that fix the legally relevant charac teristics of the meter shall be 
secured against unauthorised modification.  
(4)  The manner of verification of the parameter setting s of the meter shall be 
displayed in a conspicuous place. 
(5)  The parameters may be classified as— 11 
 (a)  unalterable, that is, the parameters have been secu red and cannot be easily accessed 
unless through a special operational mode; or  
(b)  settable, that is, the parameters can be accessed e asily by an authorised person such 
as the user or repairer. 
(6)  For the purposes of subrule (1), the zeroing of the  register that stores the total 
energy metered shall be taken as a modification of a device specific parameter.  
(7)  In these Rules, all software modules that perform r elevant functions or that 
contain relevant data domains form the legally rele vant software part of an electrical energy 
meter.  
(8)  The software modules referred to in subrule (7), sh all be made identifiable as 
prescribed under rule 15(1). 
(9)  Where the software modules that perform legally rel evant functions are not 
identified, the whole software shall be considered as legally relevant. 
(10)  Where a legally relevant software part communicates  with other software parts, 
a software interface shall be defined and all commu nications shall be performed exclusively 
through this interface. 
(11)  The legally relevant software part and the interfac e shall be clearly documented. 
(12)  There shall be unambiguous assignment of each comma nd to all initiated 
functions or data changes in the legally relevant p art of the software. 
(13)  Commands that communicate through the software inte rface shall be declared 
and documented. 
(14)  Only documented commands shall be allowed to be act ivated through the 
software interface. 
(15)  The manufacturer shall state the completeness of th e documentation of 
commands. 
17.  Separation of electronic devices and subassemblies.  
Metrologically critical parts of a meter shall not be influenced by other parts of the meter. 
18.  Data quality.  
(1)  The measurement value stored or transmitted in a me ter shall be accompanied 
by all relevant information necessary for future le gally relevant use. 
(2)  The data in a meter shall be protected by software means to guarantee the 
authenticity, integrity and, if necessary correctne ss of the information concerning the time of 
measurement.   
(3)  The software that displays or further processes the  measurement values and 
accompanying data shall check the time of measureme nt, authenticity, and integrity of the data 12 
 after having read it from the insecure storage or a fter having received it from an insecure 
transmission channel. 
(4)  The data shall be discarded or shall be marked “unu sable” if an irregularity is 
detected as a result of the checks carried out unde r subrule (3).  
(5)  Confidential keys used in the protection of data sh all be kept secret and secured 
in the electricity meter and the keys shall only be  input or read if a seal is broken. 
(6)  Software modules that prepare data for storing or s ending, or that check the data 
after reading or receiving belong to the legally re levant software part.  
19.  Data storage.  
(1)  All measurement data in a meter shall be stored aut omatically as soon as the 
measurement is concluded.  
(2)  Where the final value is from a calculation, all da ta that is necessary for the 
calculation shall be automatically stored with the final value.  
(3)  The storage device shall be sufficiently durable to  ensure that the data is not 
corrupted under normal storage conditions. 
(4)  There shall be sufficient memory storage for any pa rticular application. 
(5)  Stored data in a meter shall only be deleted when t he following conditions have 
been fulfilled— 
(a)  the transaction is settled; and  
(b)  the data is printed by a printing device subject to  legal control. 
(6)  Where the memory is full and the requirements under  subrule (5)  have been 
met, the memorised data may only be deleted under t he following conditions— 
(a)  the data shall be deleted in the same order it was recorded; and  
(b)  the deletion shall be automatic or if it manual, th e specific access rights shall apply 
before deletion. 
20.  Data transmission and internal clocks.  
(1)  The measurement of data in a meter shall not be inf luenced by a transmission 
delay. 
(2)  A measurement process shall be stopped to avoid los s of measurement data 
when network services become unavailable. 
(3)  The internal clocks in a meter shall be enhanced by  specific means such as 
software to reduce their uncertainty when the time of measurement is necessary for a specific 
field such as in an interval meter or a multi-tarif f meter. 13 
 21.  Checking facility event recorder.  
(1)  Where a meter is equipped with a checking facility,  the event recorder of the 
facility shall have enough room for at least one hu ndred events and shall be of a first-in-first-
out type. 
(2)  The event recorder shall not be changed or zeroed w ithout breaking a seal or 
without authorised access such as a password or a k ey. 
22.  Display in a meter.  
(1)  The indicating device in a meter shall be easy to r ead.  
(2)  The minimum height of the characters of measurement  results shall be four 
millimeters. 
(3)  Any decimal fraction shall be clearly indicated in the display. 
(4)  Any decimal fraction for a mechanical register shal l be marked differently. 
(5)  An indicating device shall not be significantly aff ected by exposure to normal 
operating conditions over the maximum duration of t he meter life time.  
(6)  Where a single indicating device is constructed to present multiple values, it 
shall be able to display the content of all the rel evant memories. 
(7)  For automatic sequencing displays, each display of register for billing purposes 
shall be retained for a minimum of five seconds. 
(8)  For multi-tariff meters, the register which reflect s the active tariff shall be 
indicated and shall be possible to read each tariff  register locally and each register shall be 
clearly identified. 
(9)  The register shall be capable of storing and displa ying an amount of energy that 
corresponds to the meter running at P=U nom. Imax. n for at least four thousand (4000) hours, 
where n is the number of phases. 
(10)  The retention time for an electronic register that has been disconnected shall be 
twelve months. 
23.  Test output.  
(1)  A meter shall be equipped with a test output for ef ficient testing. 
(2)  The manufacturer of a meter shall declare the neces sary number of pulses to 
ensure a standard deviation of measurement less tha n 0.1 base m.p.e. at Imax, Itr  and Imin. , 
where the design of the test output is such that th e pulse rate does not correspond to the 
measured power in every given relevant time interva l.  
(3)  The relationship between the measured energy given by the test output and the 
measured energy given by the indicating device shal l comply with the marking on the name-
plate. 14 
 24.  Durability.  
(1)  A meter shall be designed to maintain   adequate st ability of the metrological 
characteristics over a period of time specified by the manufacturer, if it is properly installed, 
maintained and used according to the manufacturer’s  instructions when in the environment for 
which it is intended. 
(2)  A meter shall be designed and manufactured such tha t significant durability 
errors do not occur and if they do occur, they are detected and acted upon through durability 
protection measures. 
(3)  A manufacturer shall provide at least one of the fo llowing forms of 
documentation for the durability of a meter— 
(a)  description of measures for durability enhancement or 
protection; 
(b)  documented experiences based on the operation of me ters of similar construction; or  
(c)  durability test procedure.  
PART IV—T YPE APPROVAL DOCUMENTATION AND IMPORTATION OF METERS 
25.  Meaning of “type”.  
(1)  All meters manufactured by the same manufacturer ma y form a type if they have 
similar metrological properties resulting from the use of the same uniform construction of parts 
or modules that determine the metrological properti es. 
(2)  A type may have several current ranges and several values of the nominal 
voltage and frequency, and include several connecti on modes and several ancillary devices. 
(3)  For purposes of this rule, “same uniform constructi on” means the same 
construction of the measuring elements, the same co nstruction of metering software, the same 
construction of the register and indicating device,  the same temperature compensation 
mechanism, the same construction of case, mechanica l block and mechanical interface. 
26.  Application for “type” approval.  
(1) An application for type approval shall be accom panied by the following— 
(a)  the identification of the type including— 
(i)  the name or trade mark; 
(ii)  the type designation; 
(iii)  the versions of hardware and software; and  
(iv)  the drawing of name plate; 
(b)  the metrological characteristics of the meter inclu ding— 15 
 (i)  a description of the principle of measurement; 
(ii)  the metrological specifications; 
(iii)  any steps which should be performed prior to the te sting the meter; 
(c)  the technical specification for the meter including — 
(i)  a block diagram with a functional description of th e components and devices; 
(ii)  the drawings, diagrams and general software informa tion, explaining the 
construction and operation including interlocks; 
(iii)  the description and position of seals or other mean s of protection; 
(iv)  the documentation related to durability characteris tics; 
(v)  any document or other evidence that the design and construction of the meter 
complies with the requirements of these Rules; 
(vi)  the specified clock frequency. 
(d)  the user manual; 
(e)  the installation manual; 
(f)  a description of the checking facility; 
(g)  the software documentation including— 
(i)  a description of the legally relevant software and how the requirements are 
met; 
(ii)  a list of the software modules that belong to the l egally relevant part including 
a declaration that all legally relevant functions a re included in the description; 
(iii)  the description of the software interfaces of the l egally relevant software part 
and of the commands and data flows via this interfa ce including a statement 
of completeness; 
(iv)  the description of the generation of the software 
identification; 
(v)  the source code which shall be made available to th e Director, depending on 
the validation method chosen;  
(vi)  the list of parameters to be protected and descript ion of protection means; 
(vii)  a description of security means of the operating sy stem including passwords;  
(viii)  a description of the software sealing methods; 
(ix)  an overview of the system hardware with diagrams to  elaborate the system 
hardware; 16 
 (x)  the identification of legally relevant hardware and  that which performs legally 
relevant functions; 
(xi)  a description of the accuracy of the algorithms; 
(xii)  a description of the user interface, menus and dial ogues; 
(xiii)  the software identification and instructions for ob taining it from an instrument 
in use; 
(xiv)  a list of commands of each hardware interface of th e measuring instrument, 
electronic device or sub-assembly including a state ment of the completeness; 
(xv)  a list of durability errors that are detected by th e software and a description of 
the detecting algorithms; 
(xvi)  a description of data sets stored or transmitted, 
(xvii)  a description of fault detecting algorithms in the software and the list of faults 
that are detected; and 
(xviii)  the operating manual; 
(h)  the type test documentation, if the test is to be b ased on the existing type approval. 
27. Importation of meters.  
(1)  A person who imports a meter of the type that has a lready received approval 
outside Uganda, shall apply to the Director, and pr ovide the information specified in Schedule 
3. 
(2)  A person who imports a meter under subrule (1) shal l ensure that— 
(a)  the manufacturer of the meter has obtained quality assurance certification conforming 
to international standards; 
(b)  the manufacturer has at least five years of experie nce in the manufacture of the meters 
in question; 
(c)  the manufacturer has supplied such meters to a mini mum of five electricity 
authorities or utilities, out of which, at least th ree are from outside the country of 
manufacture; 
(d)  the manufacturer furnishes catalogues describing th e meter which shall include the 
type, model number, construction features, material s used, technical literature, 
dimensional drawings and the type-test certificates  conforming to International 
standards; 
(e)  two meter samples are submitted to the Director tog ether with the certificates;  
(f)  the type test certificate so furnished shall contai n results on the following tests— 17 
 (i)  test of mechanical requirements; 
(ii)  spring hammer test; 
(iii)  shock test; 
(iv)  vibration test; 
(v)  test of resistance to heat and fire; and  
(vi)  tests of protection against penetration of dust and  water. 
(3)  Proof of the requirements in subrule (2) shall be g iven to the Director, at least 
three months before importation of the meters comme nces. 
(4)  In the case of requirements relating to the tests u nder subrule 
(2)(f) , the proof shall indicate the following— 
(a)  the name, address and country of the resting Author ity; 
(b)  the date of testing; 
(c)  the name of equipment type tested; 
(d)  number of pages of the type test certificates; 
(e)  manufacturer’s identity or catalogue reference numb er; 
(f)  the basic parameters; 
(g)  the standard to which the meter was type tested; an d 
(h)  the comments and observation of the testing authori ty, if any. 
PART V—F UNCTIONS OF THE BUREAU 
28. Functions of the Bureau.  
The functions of the Bureau under these Rules are t o provide for— 
(a)  the specifications relating to design, composition,  construction and performance to 
which any meter or class, type or design of meter s hall conform before permission or 
approval as regards that meter or class, type or de sign of meter; 
(b)  the specifications relating to the installation and  use of any meter or any class, type 
or design of meter; 
(c)  the manner in which meters of any class, type or de sign, or in any circumstances, are 
to be tested, verified, sealed, reverified or resea led and the manner and circumstances 
in which such meters are to be stamped, re-stamped,  labelled, relabelled, tagged, re-
tagged or otherwise marked;  
(d)  the specification in which meters of any class, typ e or design, or in any circumstances, 
are to be tested, verified, sealed, reverified or r esealed and the manner and 18 
 circumstances in which those meters are to be stamp ed, re-stamped, labelled, 
relabelled, tagged, re-tagged or otherwise marked;  
(e)  the plans for the initial verification and re-verif ication of meters of any class, type or 
design;  
(f)  the fees and charges payable by any person for any certificate, inspection or service 
provided under these Rules.  
PART VI—V ERIFICATION OF METERS 
29.  Inspector to verify meters.  
(1)  A meter shall only be verified, sealed, re-verified  or re-sealed by an inspector, 
whether the meter is verified individually or stati stically after payment of the prescribed fees 
in Schedule 4.  
(2)  A seal of any verified meter shall only be broken b y an inspector or a person 
authorized by an inspector in writing. 
(3)  A meter with broken seal shall not be put in use un til it has been verified and 
re-sealed. 
(4)  A licensee is responsible for each verified meter t hat is in use. 
(5)  A licensee shall keep a meter in good repair, and i s responsible for causing it to 
be verified from time to time in accordance with th e requirements of these Rules. 
(6)  Every licensee shall submit a meter to an inspector  for reverification at least 
once every five years.  
(7)  The licensee shall notify the Director two months b efore the due date of re-
verification. 
30.  Meter verification procedures.  
(1)  An inspector shall ensure that the test system or w orking standard used has 
sufficient accuracy to verify the meter and that it s calibration is valid. 
(2)  An inspector shall check that the meter under test is manufactured in conformity 
with the corresponding type approval documentation.  
(3)  The Director may authorize any inspector, in writin g, to verify any type or class 
of meters in accordance with international standard s in the absence of verification procedures 
in these Rules. 
(4)  A meter or type of meter verified in accordance wit h international standards 
under this rule shall be treated as if it were veri fied under these Rules. 
31.  Verification marks.  
(1)  A verification mark shall be applied to every meter  verified under these Rules. 19 
 (2)  A verification mark shall be applied either on the stamping plug or adhesive 
label of the meter and the following requirements s hall apply— 
(a)  the mark shall be easily affixed without affecting the metrological properties of the 
meter; 
(b)  the mark shall be visible without moving or dismant ling the meter when in use; 
(c)  the part on which the mark is located shall not be removable from the meter without 
damaging   the mark; and 
(d)  the size of the space intended to contain the marks  applied by the inspector shall not 
be less than 200 square millimeters. 
32.  Sealing.  
(1)  Every meter verified in accordance with these Rules  shall be sealed. 
(2)  Sealing may be mechanical or solid state, that is t o say, electronic seal or both 
mechanical and solid state, as the case may be. 
(3)  The Director may require that provision is made for  the sealing devices and 
parameters that have a metrologically significant e ffect and that determine the measurement 
result. 
33.  Inspector to apply verification mark and seal.  
Only an inspector shall apply a verification mark o r seal required to be applied to any meter 
under these Rules. 
34.  Verification certificate.  
An inspector shall issue a verification certificate  in respect of every meter that is verified and 
sealed in accordance with these Rules.  
35.  Withdrawal of meters from service.  
(1)  The Director may, by notice in writing to the owner  of any meter, require its 
withdrawal from service where the Director believes  that the withdrawal is necessary. 
(2)  A copy of the withdrawal notice shall be published in the Uganda Gazette or in 
a newspaper of wide circulation. 
PART VII—G ENERAL 
36. Delivery or sale of meters.  
A person shall not deliver, offer for sale, sell, p urport to sell, or put into use any meter unless 
that meter has been passed by an inspector as fit f or use for trade and bears valid verification 
marks indicating that it has been passed  as provid ed for under these Rules.  
37. Offences related to meters.  
(1)  A person who— 20 
 (a)  without authority makes, causes or procures to be m ade, or assists in making any 
certificate under these Rules or purporting it to b e a certificate so required or any 
stamp, seal, label, tag or mark prescribed for the purposes of these Rules or purporting  
it to be a stamp, seal, label, tag or mark; 
(b)  knowingly sells, utters or disposes of, lets, uses,  lends or exposes for sale any meter 
with any stamp, seal, label, tag or mark made or ob tained by means other than means 
provided for under these Rules; 
(c)  in relation to the administration of these Rules, k nowingly— 
(i)  makes any false representation; 
(ii)  makes or causes to be made any false entry in any r egister or record, 
(iii)  makes or causes to be made any false document or ma kes any alteration, false 
in a material particular, to the form of a copy of any document; or 
(iv)  produces or tenders any document containing false i nformation, 
(d) for a fraudulent purpose, repairs or alters, or  causes to be repaired or altered, or tampers 
with or does any other act in relation to a meter, or any wire leading to a meter, so as 
to cause the meter to register with an error or rep laces any meter with a meter likely 
to mislead,  
commits an offence. 
(2)  A person who contravenes sub-rule (1) commits an of fence and is liable on 
conviction to a fine not exceeding three currency p oints or imprisonment not exceeding 
three months or both. 21 
 SCHEDULE 1  
Rule 5  
CERTIFICATE OF VERIFICATION OF WORKING STANDARD  
I certify that the Working Standard meter with unde r listed particulars has this day been duly 
calibrated in my presence by comparison with the Re ference  
Standard in accordance with the Weights and Measure s (Electrical Energy Meters) Rules 2014.  
(a)  Manufacturer’s mark or name ………………………………………  
(b)  Accuracy class, type or design of the meter ………………… …….....  
(c)  Meter Serial Number………………………………………………..  
(d)  Previous Seal No. …………………………………………………….  
(e)  New seal No. ………………………………………………………  
(f)  Expiry date. ………………………………………………………….. (g) Next date  of 
calibration. …………………………………………….  
(h)  The errors, if any, of the meter at all points test ed……………………  
(i)  Signature…………………………………………………………. (j) Name 
…………………………………………………………………  
( In block letters )  
(k)  ( Executive Director of Uganda National Bureau of S tandards )  
  Dated this ……………day of ………………………., 20.......  
SCHEDULE 2  
Metrological requirements Rule 6(1)  
Table 1: RATED OPERATING CONDITIONS  22 
  
Humidity 
and water  
Connection 
modes  With respect to humidity, the manufacturer shall sp ecify the environment class 
for which the instrument is intended:  
H1: enclosed locations where the instruments are no t subjected to condensed 
water, precipitation, or ice formations;  
H2: enclosed locations where the instruments may be  subjected to condensed 
water, to water from sources other than rain and to  ice formations;  
H3: open locations with average climatic conditions .  
The manufacturer shall specify whether the meter is  intended for direct 
connection, connection through current transformers  or through current and 
voltage transformers.  
The manufacturer shall specify the connection modes , the number of measuring 
elements of the meter and the number of phases of t he electric system for which 
the meter is intended.  
  Meters may be categorized as follows:   
  No. of phases  No. of wires  No. of elements  
 single  two  1 
23 
  single  three  1 
 single  three  2 
 three  four  3 
 three  three  2 
 two  three  2 
Tilt_____  Mounting position as specified by the manufacturer ±3 degrees. If no mounting 
position is given, any mounting position is allowed .  
Harmonics  The voltage and current shall be allowed to deviate  from the sinusoidal form, as 
given by the requirements in Table 4 –‘Harmonics in  voltage and current circuits’  
The load balance shall be allowed to vary from full y balanced conditions to  
Load current in only one current circuit for poly-p hase meters and for single –phase Balance  
3- wire meters.  
Table 2: BASE MAXIMUM PERMISSIBLE ERROR AND NO LOAD   
REQUIREMENTS  
Quantity  Base maximum permissible errors(%) 
for meter s of class  
A B C D 
Current I where Itr ≤ I  ≤   Imax,      
and power factor variation 
from 0.8 to1 to 0.5 inductive  ±2.0  ±1.0  ±0.5  ±0.2  
Current I where Imin ≤I< Itr, at 
unity power factor  ±2.5  ±1.5  ±1.0  ±0.4  
Current I 
where Ist ≤I< 
Imin, at unity  
power 
factor  Direct 
connected 
meter  ±2.5 *Itr/(2 *I) ±1.5 *Itr/(2.5 *I) ±1.0 *Itr/(5 *I) ±0.4 *Itr/(5 *I) 
Transformer 
operated  
meter  ±2.5 *Itr/(2.5 *I) ±1.5 *Itr/(2.5 *I) ±1.0 *Itr/(5 *I) ±0.4 *Itr/(5 * I) 
No load  No significant metered energy as given by the 
corresponding test  
Table 3:  LIMITS OF TEMPERATURE COEFFICIENT OF ERRO R  
Influence quantity  Power factor  Limits for temperature coefficient (%K) for 
meters of class  
A B C D 
Temperature coefficient(%K), 
over any interval within the 
temperature range which is not 
less than 15 K and not greater  
than 23 K, for current  Itr ≤ I  ≤   Imax  1 ±0.1  ±0.05  ±0.03  ±0.01  
0.5 inductive  ±0.15  ±0.07  ±0.05  ±0.02  
Table 4: LIMIT OF ERROR SHIFT DUE TO INFLUENCE QUAN TITIES  
Influence 
quantity  Value  Test  
Schedule  Value of 
Current  Power 
factor  Limits of error shift(%) for 
meters of class  
    
     A B C D 
Temperature 
dependence  Over entire 
specified 
temperature 
range  Seventh  
Itr ≤ I≤ Imax  1 
±3.3  ±1.7  ±0.7  ±0.3  0.5 
inductive  
Load balance  Seventh  1 ±1.5  ±0.7  ±0.2  ±0.1  24 
 Current in 
only one 
current 
circuit  Itr ≤ I≤  
Imaxssss  0.5 
inductive  
Voltage 
variation  
Unom ± 10%  Seventh  
Itr ≤ I≤ I 
max  1 ±1.0  ±0.7  ±0.2  ±0.1  
0.5 
inductive  ±1.5  ±1.0  ±0.4  ±0.2  
841 
Frequency 
variation  
fnom ± 2%  Seventh  
Itr ≤ I≤ I 
max  1 ±0.8  ±0.5  ±0.2  ±0.1  
0.5 
inductive  ±1.5  ±0.7  ±0.2  ±0.1  
Harmonics          
in voltage and 
current 
circuits  D is 0 -40% I, 0-5 
%U Seventh  
Itr ≤ I≤ Imax  1 ±1.0  ±0.6  ±0.3  ±0.2  
Tilt  ≤ 3 degrees  Seventh  
Itr ≤ I≤ Imax  1 ±1.5  ±0.5  ±0.4  n.a  
Damp heat  Humidity class  Seventh  Itr ≤ I≤ Imax  1 ±0.2  ±0.1  ±0.05  ±0.02  
Severe voltage 
variation  0.8 Unom ≤  
U< 0.9  Unom  
1.1  U nom <  
U≤1.15  Unom  
U< 0.8  Unom  Seventh  
As 
defined 
in test  1 ±1.5  ±1  ±0.6  ±0.3  
+  10  to   -100  
One or two 
phases 
interrupted   
Seventh  As 
defined  
in test  1 ±4  ±2  ±1  ±0.5  
Sub -         
harmonics in 
the AC 
current 
circuit  Two periods 
on, two periods 
off  Seventh  As 
defined  
in test  1 ±3  ±1.5  ±0.75  ±0.5  
 
Influence 
quantity  Value  Test 
Rule  Value 
of 
Current  Power 
factor  Lim its of error shift(%) for 
meter s of class  
    
     A B C D 
Harmonics in 
the AC current 
circuit  Phase - 
fired t 90 
degrees  Seventh  As 
defined  
in test  1 ±1  ±0.8  ±0.5  ±0.4  
Reversed phase 
sequence  Any two 
phases inter-  
changed  Seventh  As 
defined  
in test  1 ±1.5  ±1.5  ±0.1  ±0.05  
Continuous 
(DC) magnetic 
induction of 
the external 
origin  200  mT 
at30mm  
from core 
surface  Seventh  As 
defined  
in test  1 ±3  ±1.5  ±0.75  ±0.5  
Magnetic          25 
 field(AC power 
frequency) of 
external origin  400A/m  Seventh  As 
defined  
in test  1 ±2.5  ±1.3  ±0.5  ±0.25  
Radiated RF 
electromagnetic 
fields  f=80 to  
6000 MHz ≤10 
V/m; 
Amplitude 
modulated  Seventh  As 
defined  
in test  1 ±3  ±2  ±1  ±1  
Conducted          
disturbances 
induced by 
radio frequency 
fields  f=0.15to 80  
MHz  
≤10 V/m; 
Amplitude 
modulated   
As 
defined  
in test  1 ±3  
±2  ±1  ±1  
DC in the AC 
Current 
circuit  Sinusoidal 
current, twice 
amplitude, 
half-wave 
rectified  I≤  
Imax / 2   
As 
defined  
in test  1 ±6  ±3  ±1.5  ±1  
High- order 
harmonics  Superimposed:  
0.02 Unom,  
0.1 Itr; 15 fnom to 
50 fnom   As 
defined  
in test  1 ±1  ±1  ±0.5  ±0.5  
Table 5: Disturbances  
 Disturbance 
quantity    Test Settings  Allowed effects  Limits of error shift(%) for meters 
of class  
A B C D 
Magnetic 
field(AC,power 
frequency) of 
external origin   1000 A/m,3 s  No significant 
fault as given by 
the corresponding  
test  - - - - 
Electrostatic 
discharges   6 kV contact 
discharge,8 kV 
air discharge  No significant 
fault as given by 
the corresponding  
test  - - - - 
Fast transients    Voltage and current  
circuits  
4 kV; auxiliary 
circuits 2kV  No significant 
fault as given by 
the corresponding  
test  6.0  4.0  2.0  1.0  
Voltage dips   Test (a): 30%,0.5 
cycles  
Test (b): 60%,1  
cycle  
Test (c): 60%, 25/30 
cycles  No significant 
fault as given by 
the corresponding  
test  - - - - 
Voltage 
interruptions    0%,250/300 cycles  No significant 
fault as given by 
the corresponding  
test  - - - - 
 26 
 Radiated, RF, 
electromagnetic  
fields   f=80 to 6000 
MHz,30 V/m, 
amplitude 
modulated, 
without current  No significant 
fault as given 
by the  
corresponding 
test  - - - - 
Surges on AC 
power lines   Voltage circuits: 
2 kV line to line. 
4 kV line to 
earth. Auxiliary 
circuits: 1 kV 
line to line, 2 kV 
line to earth.  No significant 
fault as given 
by the 
corresponding 
test.  - - - - 
 
Disturbance 
quantity   
Test Settings  Allowed effects  Limits  of error shift(%) for 
meters  of class  
A         B        C           D  
Damped  
oscillatory waves 
immunity   Voltage circuits:  
Common  
model 2.5  kV 
Differential 
model 1.0 kV  No significant 
fault as given 
by the 
corresponding 
test.  - - - - 
Short time 
overcurrent   
Direct connected  
meters: 30. I max, 
Transformer 
operated meters:  
20. I max   No significant 
fault as given 
by the 
corresponding 
test. No 
damage shall 
occur.  Transf ormer o perated  
1.0  0.5  0.05  0.005  
Direct  connected  
1.5  1.5  0.05   
Impulse voltage   
Refer to Rule  No significant 
fault as given 
by the 
corresponding 
test. No 
damage shall 
occur.  - - - - 
Earth fault   
Earth fault in 
one phase  No significant 
fault as given 
by the 
corresponding 
test. No 
damage shall 
occur.  1.0  0.7  0.3  0.1   Operation of 
auxiliary devices   
Auxiliary devices 
operated  
with   I=Itr and Imax  No significant 
fault as given 
by the 
corresponding 
test.  1/10  of base 
m.p.e.  ½ of base 
m.p.e.  
Vibration   Vibration in the 
three  mutually 
perpendicular 
axes  No significant 
fault as given 
by the 
corresponding 
test.  1/10 of base 
m.p.e  ½ of base 
m.p.e.  
Shock   
Refer to test Rule  No significant 
fault as given 
by the 
corresponding 
test.  1/10 of base 
m.p.e  ½ of base 
m.p.e.  
Protection  
against solar 
radiation   
Refer to test Rule  No alteration in 
appearance or 
impairment in 
functionality, 
metrological 
properties and 
sealing  - - -  -  
 Disturbance 
quantity    Test Settings  Allowed effects  Limits of error 
shift(%) for 
meters of class   
A B C D 
Protection  
against  ingress 
or dust   
Refer to test Rule  No interference 
with correct 
operation or 
impairment  
of safety, 
including 
tacking along 
creepage 
distances.  - - - - 
Extreme 
temperatures   
Refer to test   
Rule  No significant 
fault as given 
by the 
corresponding 
test.  1/10 of base 
m.p.e.  ½ of ba se 
m.p.e.  
Humidity and 
water   
Refer to test   
Rule  No significant 
fault as given 
by the 
corresponding 
test.  - - - - 
 
SCHEDULE 3  
Rule 27  
APPLICATION FOR PERMISSION OR APPROVAL TO IMPORT ME TERS  
Subject to Rule 29, any person with an intention to  import meters into Uganda shall apply to the Direc tor, indicating the following 
particulars.  
1.  An application for permission or an approval referr ed to in Rule 29 of these Rules, shall be made in w riting to the Director 
and shall contain the following information:  
(a)  the name and principal place of business of the app licant;  
(b)  information sufficient to describe clearly the desi gn, composition, construction and 
performance of the meter or the class, type or desi gn of meter, to which the application relates;  28 
 (c)  data that indicate whether the meter or the class, type or design of meter to which the application re lates meets all 
applicable requirements of these Rules, and specifi cations.  
(d)  where the manner of installation or use affects the  performance of the meter or meters of the class, t ype or design to 
which the application relates, the manner in which the meter or each meter of the class, type or desig n is to be installed 
and used;  
(e)  a copy of any promotional material, instructions an d other information distributed or intended for dis tribution to 
purchasers or prospective purchasers of the meter o r the class, type or design of meter to which the a pplication relates; 
and  
(f)  such additional information in respect of the meter  or the class, type or design of meter that is nece ssary for the 
purposes of the application.  
2.  An applicant shall make available to the Director o ne or more meters of the class, type or design of m eter to which the 
application referred to relates, and shall also mak e available such equipment, material and services a s are required to inspect 
and test the meter or meters.  
3.  Where the Director grants an approval under these R ules, he or she shall specify in writing in the app roval, any conditions 
to which the approval is subject.  
 
SCHEDULE 4  
Rule 29 Verification Fees  
Location of Meter  Total Verification Fees-Shillings  
In House (New Meters)  8,000  
In Service (In Field)  25,000