Re-take - Useful Information for 2394 :

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Continuingwith the names .( Generic )

RCD- residual-current-device . This is a “ Generic-term “ for the entire-family ofRCDs

RCCB. -

RCBO- residual-current-breaker With Overcurrent-protection . this is basically an .Overcurrent-sensing-circuit-breaker - such as an ” circuit-breaker “
Withan RCD - added to it .

RCBO- it has two - functions .
-to provide protection against - Residual-currents .
-to provide protection against - Overload-current .

“ Generic-term “ for the entire-family of RCDs- RCBOs -Circuit-breaker & RCD .


(I always kick myself for not knowing what seems Obvious when Explained . )

RCBO- now we ask the Question . why is an RCD .placed in Table - 41.3.this Answer is simple !!! . you are using the ( Circuit-breaker side of the RCD )
for Maximum earth-fault-loop-impedance - ( Zs )
p.56. Regulations . reminds us . by defection . Overcurrent- characteristics . ◄ We can shut thebook on this one .

inthe Regulations - we use different RCDs . Basics . Additional-categories .

Typeof . protection-provided by RCD . ??? categoriesthat can be used .
Type- AC . device . which detect-pure . A.C. residual-currents Only .
Type- A . device . which detect residual-currentscomprising of pure - A.C. pulsating -D.C.
Type- B . device . which detect residual-currentscomprising of pure - A.C. rectified -A.C. & pure D.C.

2394: You don’t have to get lost in this matter . ▲

This Matter you will .need to understand - for your 2394 : Exams .
RCDsare divided in to ( Two-categories ) based on their ( Response-time ) to a .residual-current
(G ) - general - type . for yourexam-purposes’ “ Instantaneous “
Delay-response( S-type )

Shouldbe fairy-obvious with all your studying . “ Factors “ that we have to take intoconsideration - Rated-voltage : Load-current : Number-of poles ?? :Residual-currents : Etc .

Discriminationin term of ( IΔn) times .” tΔ“
ReminderP.26 : Discrimination . Ability of a “Protective-device . to operate in preference to another-protective-device . in SERIES .

ReminderP.25 : is by Definition - Circuit-breaker .
Wewill open this up .
Circuit-breaker- Device capable of making . carrying & breaking ( Normal-load-currents )
So-fault-conditions!! . Under-predetermined-conditions . ( Abnormal-currents . such as Short-circuit-currents ) ≈ ≈

RCDs- Leakage-current !! Nuisance-tripping .
Thismeans that for a . 30mA - RCD the standing-leakage-current . should not exceed. 10mA . given that a . 30mA - RCD may trip anywhere from . ( 15 / 30mA )
Inother words . 10mA - standing-leakage-current . will virtually-PRIME . the RCD to trip . & an Earth-fault-current.

Example . Under fault-conditions . !! .
Thesum of these Two-currents . is the residual-current - seen by the RCD . & if this current is greater than its . Rated-trip-current. as we know . RCD will Trip .

 

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GN-3. p.53
2394oint to Note . ( Ze at the Origin ) forDomestic-Installation in our case .

GN-3. reminds us .
ForLarger-installations with consumer-units . or distribution-boards - ( Not at the Origin ) therecan arise . confusion over the “ Term “ External-earth-loop-impedance( Ze ) & some prefer to Write orNote the . earth-fault-loop-impedance at the . ( distribution-board as Zdb ) as . Strictly-speaking . this value is not . External to the installation. Thus . the formula is denoted . ( Zs = Zdb + R[SUP]1[/SUP]+ R[SUP]2[/SUP] )

 

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2394: Where the Consumer-unit is at theOrigin of the Installation . Zs = Ze+ ( R[SUP]1[/SUP] + R[SUP]2[/SUP])
2395: Where the Distribution-board . is a sub-main somewhere Etc . Zs = Zdb+ ( R[SUP]1[/SUP] + R[SUP]2[/SUP])

 

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(As Many of our Learner-Colleagues on this forum . has said many a time )

2394: We can not take lightly . Testing & Inspection . there is no Quick-fix solution here . GN-3& BS-7671:2011 . by reading theses . They give you an Idea of thestructure involved . with . Testing & Inspection .

 

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Atyou disposal - GN-3 & BS-7671:2011: ( What youput in you’ll get Out )

p.34. RCD is defined - BS-7671:2011: as “ A Mechanical-Switching-Device “ orassociation of devices intended to cause the opening of the contacts when the .residual-current attains a given value under specified-conditions .

GN-3- p59 .
BS-7671:2011:- 612.13.1.
TheRCD incorporates a check-button which should be tested on Quarterly-basis .

GN-3- p59 .
Integral-Test-Device.
Anintegral-test-device is incorporated in each RCD . This device enables the (Functioning of the mechanical parts of the RCD ) to be verified by pressing thebutton marked “ T “ or Test .

GN-3is telling us . 2394 : Operation of the integral-test device does “ NOT “ provide a means of Checking :

-The Continuity of the ( Earthing-Conductor ) or the associated .Circuit-Protective-Conductors - ( CPC )
-Any Earth-Electrode(s) or Other means of earthing .
-Any other-part of the associated . Installation-Earthing .
-The ( Sensitivity of the Device )

-&-s: The RCD - Test-button will ( ONLY ) operatethe RCD if it is ( Energized )


Forour Younger members . go into the forum with any Questions ( Big or Small )

 

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“ At Radom“

Example. O.S.G.- p.29. Typical-split-consumer-unit . TN- TT- Installation(s) 2394omestic-Installation . must be Class-11 Enclosures’ ( C/U)
Class-1. Exposed-conductive-parts . ( Metal ) Distribution board

Measurementof ( Ze ) the Origin of the Installation . 2394: “Example “
-As this requires the removal of Covers & the Exposed-conductive-parts. ( Isolation )Main-switch - ( 100A Isolator )

As 2394 ( Installer ) You are installing a . Class-11 Equipment . .Protection against Electric-shock . (Barriers or Enclosures .416.1. ) “ Domestic “ Ordinary- persons

 

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“At - Radom “

Protection: By definitions . of Persons &Livestock .

Part - 2 . BS-7671:2011:

p.23 . Basicprotection : Protection against . Electric-shock . under fault-free conditions.
p.27 . Electric shock: A dangerous physiological effect resulting from the passing of an .Electric-current . through a human body or livestock .
p.27 . Exposed-conductive-part : Conductive -part of equipment which can be touched &which is not normally live .“ but “ whichcan become live under fault-conditions .
2008 . Exposed-conductive-part : Conductive - part ofequipment which can be touched & which is not normally live .“ but “ whichcan become live when basic insulation fails .
p.28 . Extraneous-conductive-part: Conductive-part .liable to introduce a potential . generally Earth potential . & not forming part of the electrical installation .
p.28 . Faultprotection : Protection against Electric-shock . under single fault conditions.
p.30 : Live-part :A Conductor orConductive-part .intended to be energized in normal use . including a neutral-conductor “ but “by convention . not a PEN-conductor .
p.34 : Shock current :A current passing through the body of a person or livestock such as to . causeelectric-shock & having characteristics likely to cause dangerous effects .

-Existing on or coming from the Outside < Ex-tra-ne-ous . adjective .
Canbe confused : Extraneous . External . Internal .
-No forming an Essential or Part < Extraneous .( not forming part ofthe electrical installation )

AQuestion we must ask yourself . ( Can it ) Introduce apotential . Generally earth potential .
Extraneous“ because they do not comprise part of the Electrical Installation .

Wecan over look . the true meaning off . is it . Classed as an . Exposed-conductive-part .? as opposed to anExtraneous-conductive-part . ?
Todecide whether or not a specific item of “ Metalwork “ or Other “ Conducting material is an . Extraneous-conductive-part.

Mayby definition AS - 2011 :
p.28 . Extraneous-conductive-part: Conductive-part .liable to introduce a potential . generallyEarth potential . & not forming part of theelectrical installation .
thedefinition is considered in three portions .

i) . “ Conductive-part“
(in most situations . Only parts which are made of Metal need to be consideredas Conductive-parts )

ii) . “ Liable to introduce a potential . generally earthpotential .
( You are askingyourself . Sourceof Potential !! . potential whichis generally of interest is Earth-potential . Electrical-potential of “ The “Conductive mass of Earth .which is conventionally takenas Zero . this is normally the potential of an item such as a ( Metalpipe ) which is buried in the ground . Or . Structural steel column which is ina foundation in the ground .

iii) . “ & Notforming part of the Electrical Installation .

 

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Someof this stuff I have not brought up to 2012 .

SomethingI knocked up . ( Jan - 2012 ) 2394it will give you an Idea . some where to startto study .

Standards: Inspection & test shall be carried out in accordance with therequirements of the following . BS-7671:2011: including Guidance Note 3 : 2012.

Wherea tester is offered with a free manufactures calibration certificate . this isissued at the time of manufacture & is valid from date the equipment is commissioned into Use .
May be Required : Calibration Certificates for alltest equipment used will be required at the start of the contract & as thecontract progresses .
Responsibilitiesof the Inspector .

GN-3 . is givesus . General Guidance .
Firstly. Inspection & . procedures &Acceptance Criteria .
Onits. Own Merits . Design Verification . which will result in Validation .

Instrument(s). that define how an “ Activity “ iscarried out in relation to a specific product . BS-EN- 61557 - ? . part ?
AcceptablePractices . Standard(s)) . Regulation(s)) . & Specification(s)). comply with regulatory procedures .

Manufactures.The responsibility for their conformity to an Agreed Specification .
Testrequirement : The stimulus . Measurement . power . load(s). any test equipmentor procedure essential to ( Validate ) proper operation of a device or somepredetermined design control or product specification definition .

Whatis the Difference between BS-EN-61010 : & BS-EN-61557 :

Firstly: Standards
Toensure the safety of the electrical installations & their safety during Testing .

BS-EN-61010 . Safetyrequirements for electrical Equipment for measurement . control &laboratory use . &
ThisStandard has been established with the aim to define the “ General Safety “ requirements for MeasuringInstruments .

BS-EN-61557 ;Electrical Safety in low voltage distribution systems up to 1000V A.C. &1500V D.C. , Equipment for testing . measuring or monitoring of protectivemeasures . this standard includes performance requirements & requirescompliance with BS-EN-61010 .

GN-3 – Verification .
ThisSeries of standards has been established with the aim of stipulation commonprinciples ( of features & safety ) for TestingInstruments used for electrical installations up to 1000V A.C. &1500 D.C. .

Series- BS-EN-61557 : Additional safety . Accuracy& Operation .
TheBS-EN-61557 . Standard is ( Divided ) into several parts .each of them dedicated to one measurement or argument as follows :

Firstly: Standard of
BS-EN-61557 . Part 1 : ? what does this mean .

Simple:
BS-EN-61557-1- ProtectiveMeasures . : ( Status/ Current ) Electricalsafety in low-voltage distributionsystems up to 1000V A.C. & 1500V D.C. You are addressing the issue of . Equipment fortesting .

BS-EN-61557: consistsof a number of parts . some of which are indicated .
Generalrequirements .

Terminologyfrom GN-3
“ Conformity “ – BS-EN-61557 . Part 1 . Generalrequirements :
“Conformity “ – BS-EN-61557 . Part 2 . Insulation résistance tester :
Verification– GN-3 - BS-EN-61557-2 .
“Conformity “ – BS-EN-61557 . Part 3 . Earth fault loop impedance ;
Verification– GN-3 - BS-EN-61557-3 .
“Conformity “ – BS-EN-61557 . Part 4 . Low résistance ohmmeter tester . ( résistance& continuity ) of earth connections & equipotential bonding :
Verification– GN-3 - BS-EN-61557-4 .
“Conformity “ – BS-EN-61557 . Part 6 . Residual current devices – ( RCD tester ) :Effectiveness off .
Verification – GN-3 - BS-EN-61557-6 .
“Conformity “ – BS-EN-61557 . Part 7 . Phase – sequence :
Verification– GN-3 - BS-EN-61557-7 .

 

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TestInstruments for Electrical Installation(s) :
Tocomply with Regulation 612.1. of BS-7671:2011 . test instruments must be selected according to therelevant parts of BS-EN-61557-1 or if not .they must provide an equivalent level of performance . BS-EN-61557 requirescompliance with the safety requirements of BS-EN-61010 .

Point to Note :Two or more of the functions of the above test Instrument(s) may be combined ina Single-Instrument . ◄► “ Point to READ “

Exams purposes : Standardsin force . this guide is intended for persons carrying out the Testing of Low-voltage installations .
Wewill focus on Various testing regimes & the stipulated values which these (Tests ) should deliver .

Weare now complying with . BS-7671:2011 :
Requirementsfor Testing an Electrical Installation .
ElectricalTesting & Measurement(s) .

612.2.1.– Continuity of the protective conductors . including main & supplementarybonding :
612.2.2.– Continuity of the ring final circuit conductors :
612.3.– Insulation résistance of the electrical installation : Scope of Test . Limits– Table 61 .BS-7671:2011. Measuring Instrument(s) BS-EN-61557-2
•Basic protection by a barrier or enclosure . provided during erection ( generally determined by visual inspection ) Regulation. 612.4.5.
612.6.– Polarity :
612.7.– Earth electrodes résistance . when required : or - where the electrode is part of theinstallation .
Alternatively: for TT system the installation . Earthelectrode résistance may be approximately measured with the incoming supply .energized & main switch Off . using an Earth fault loop impedance testinstrument .
612.9.– Earth fault loop impedance :
BS-EN-61557 . Part 6 .Effectiveness of residual current devices ( RCD ) in TN- : TT- systems .
GN-3to BS-7671:2011 :
RCDsused for :
1)protection against fire . 612.8.
2)Fault protection . or 612.8.1. (a) & ( b)
3)Additional protection . 612.10.
612.10.– Additional protection :
WhereRCDs are required for additional protection . the effectiveness of automaticdisconnection of supply by RCDs shall be verified usingsuitable Test Equipment according to BS-EN-61557-6
Inspection / Visual checking shall be donefirst before any measurement . RCDs . 612.11.
– ( PFC )
612.13. – Functional testing :


- - - Updated - - -

Functionaltesting of RCD – using test facility indevice . 612.13.1.
Functionaltesting of switchgear & controlgearassemblies . drivers . control & interlocks . 612.13.2.
Verificationof voltage drop . note : this is not normally required initial verification . 612.14.

Verification:

Orderof Test(s) for the initial verification of an installation as “ Required “ by Regulation – 612.1.BS-7671:2011 :
Requiresthat . ?
-Test results are compared with relevant “ Criteria “
-Test that “ Indicates “ a failure to comply withthe “ Criteria “ is repeated after the fault is rectified.” Together withany preceding test influenced by the fault “

Testsmust “ NOT“ be carried out until inspection has been completed . as required byRegulation . – 611.1. - Disconnected from thesupply .

Orderof Tests . Where relevant . to be carried out ( Before) the supply is connected or with the supply disconnected as appropriate .
Orderof Tests . Where relevant . to be carried out ( After ) the tests . have been completed& the supply connected .- “installation been Energized “

“Installation been Energized “ RCD usedfor :
-Protection against fire . – 612.8 .
-Fault protection . Or .

612.8.1.- (a) (2) TN- system .
(2). Verification of characteristics & / or the “ Effectiveness “ of the associated protective device . Thisverification shall be made :
-for overcurrent protective devices . by ( Visual Inspection ) short-time orinstantaneous tripping setting for circuit-breakers . Etc .

Complying: for RCDs by ( VisualInspection ) & Test .
Conducting. Inspection & Testing .
“ Visual Inspection “ fundamental principles . we are Complyingwith . Measureof Protection for Safety

VisualInspection is “ ExtremelyImportant “ & should alwaysprecede Testing . the purpose of the visual inspection is to confirm thefollowing aspects of any installation .
-The “ Effectiveness “ of Automaticdisconnection of supply by RCDs shall be “ Verified “ using “ Using suitabletest equipment according to BS-EN-61557-6 .
Regulation– 612.1 . to “ Confirm “ that the relevantrequirements in Chapter 41 are Met .
Chapter 41 .Protection against Electric-shock .
Additionalprotection . – ( ADS ) 612.10 . “ Verification “
Ofthe “ Effectiveness “ of the measuresapplied for additional protection is fulfilled by ( VisualInspection ) & Test .
WhereRCDs are required for additional protection . the “ Effectiveness “ of automatic disconnection of the supply byRCDs shall be Verified using ( Suitable Test Equipment ) according to BS-EN-61557-6 . See Regulation 612.1. to ( Confirm) that the relevant requirements in Chapter 41are Met .

itis important that all ( Measuring Instruments )& monitoring equipment used for above tests comply with the Series . BS-EN-61557-?

 

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The disconnection times required by Chapter 41 . shall be Verified .
TT– system : 612.8.1.
2)Verification of the characteristics & / or effectiveness of the associatedprotective device . This verification shall be made :
forRCDs .by visual inspection & Test . the effectiveness of automatic disconnection of the supply by .RCDs shall be verified using suitable test equipmentaccording to ( BS-EN-61557-6 ) see regulation 612.1. toconfirm that the relevant requirements in Chapter 41 are met .

UsefulJunk : RCDs : Why’s & How’s 312.2.1.1. -
Thetest parameters detailed in Appendix 3 . arein accordance with the requirements of the relevant . ProductStandard – BS-EN-61008 part 1 &BS-EN-61009 part 1
whichsatisfy these requirements . “ as we known them as “ BS-EN-61008-1 & BS-EN-61009-1

Verification: All measures by means of which compliance of the electrical installation withthe relevant requirements of BS-7671:2011. are checked . comprising Inspection. Testing . & Certification .

Instrumentaccuracy . calibration . re-calibration .
Provedaccuracy & consistency of test instrument(s) during lifetime is requiredfor “ Verification “ purposes .

GN-3 : Accuracy . Instrument(s) must be designed &approved according to the BS-EN-61557 . Standards

ValidCalibration of the Instrument :
-New instrument must be provided with a “ ValidCalibration Certificate “ from the manufactures.
-Calibration Certificate “ from accredited laboratories are the most valuableones .


- - - Updated - - -

Accreditedlaboratories are subjected to a very strict control . their results can beconsidered as Accurate & traceable .

UsefulJunk : ( Marked on your Tester )

Reason’s◄► Overvoltage’s Protection Categories for Installation Testers .
Overvoltageprotection category as defined in BS-EN-61010-1 – Line to Earth .
Cat11 – 600V . Transient test voltage .4000V
Cat111 – 300V . Transient test voltage .4000V
Cat111 – 600V . Transient test voltage .6000V
Cat1V – 300V . Transient test voltage .6000V .
Cat111 – 1000V . Transient test voltage .8000V
Cat1V – 600V . Transient test voltage .8000V

ElectricalEquipment :
Anyitem for such purposes as generation .conversion .transmission . distributionor utilisation of electrical energy . such as machines . transformers .apparatus .
( Measuringinstruments ) protective devices . wiring systems .accessories & luminaries .

CompetentPearson :
Aperson who possesses sufficient technical knowledge & experience for thenature of the electrical work undertaken . & is able at all times toprevent danger . & where appropriate injury . to themselves & others .


- - - Updated - - -


Testing:
Implantationof measures to assess an electrical installation be means of which its ( Effectiveness is proved ) this include ascertainingvalues by “ means of appropriate measuring Instruments “ where measured values are ( Not detectable by Inspection alone )

InterpretingSpecifications. You as the User / Inspector(s) must determine whichspecifications are relevant to the Application BS-EN-61557. interpretationof performance specifications .
Manufacturer specifications are used for a givenmeasurement application . BS-EN-61557.

Supplierclearly has responsibilities for specific design . work functions onInstruments . specified requirementsplaced on the potential market functional & operational requirements .

Designvalidation goes beyond the purely technical issues of verifying that the deignoutput meets the design input . & isintended to ensure that the product meets User requirements .

GN-3 - Establishing an effective method of proving theaccuracy of test instrument(s)is of paramount importance .
BS-7671:2011: offersno guidance as to the method that should be employed to ensure consistency& accuracy other than requiring that the results of Testing are comparedwith the relevant criteria .

“ But “ it is a requirement to comply toRegulations’. It quite clearly states in the Regulations what the minimum performance that is expected from your Testers.

Sequenceof Tests :
Testingof Electrical Installation(s)can be divided into two distinct part(s)
Teststo be carried with the supply disconnected .
Teststo be carried out before the supply is connected .

 

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Question!!

Whichever Instrument(s) we are using at the time ??
Itis the responsibility of the User . ( One Operative) to ensure that the system provides confidence in the Test Results used toVerify or confirm the Safety of an Electrical Installation .

When submitting an Instrument for calibration . the User should ask to beAdvised if it was found to be Inaccurate.

Conformity with the requirements of this standard is checked bycarrying out all applicable test(s) .

-European Standard EN-61010-1 : has the status of a British Standard .BS-EN-61010-1 .

BritishStandards to which Reference is made in the Regulation. Appendix 1 . ( Normative ) p.288. – 612.1. / 621.3.

 

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Theverification of the effectiveness applied for Additional Protection isfulfilled by Visual inspection & test . where RCDs are required for Additionalprotection .
theeffectiveness of automatic disconnection of the supply by RCDs shall beverified using suitable test equipment according to BS-EN-61557-6 :
seeregulation 612.1. to confirm that the relevant requirements in Chapter 41 areMet .

LegalRequirements : ( Facts )

TheElectricity at Work Regulations – 1989 . are theprincipal legislation relating the Electrical Testing Activities .

Regulation4 (3) requires that “ Work on or near to an electrical system shall be carriedout in such a manner as not to give rise so far as is reasonably practicable .to danger “
Regulation14 . places a strict prohibition on working on or near Live conductors unless :
a)it is unreasonable for the equipment tobe dead .
b)it is reasonable for the work to take place on or near the Live conductor ;&
c)Suitable precautions have been taken to prevent injury .

Scopeof the Work is to give a “ Professional Opinion“ of the installation condition by carrying out ( Visual Inspection(s) & Instrument testof these parts of the installation which areaccessible .

TheIntention of the Regulation(s) . is to provide an Undertaking . therequirements of which are set down in the :
Electricityat Work Regulation . 1989 .
BritishStandards . No – BS-7671:2011 : as amended .
IET. Guidance Note 3 Inspection & Testing :incorporating Amendment No – 1:2011 .

Inspection:
Inspectioncomprising careful “ Scrutiny “ of every Installation .

 

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Ramp ( Time ) Testing :
Thegradual increase of voltage from zero potential over a period of time . ( Step ) that iswhy we see . bars ( Step) showing on or Megger 1552 .
-“ Ramp Test ” ) . measures the RCD trip current . the ramp test displays theactual trip current on all RCD ranges instead of trip time . ( Ideal for identifying nuisance tripping RCDs )
Ramptesting : for measuring the tripping level in mA.

TheNature of the Regulations is that they must state all facts .


- - - Updated - - -

□Tips : Do not exceed 4mm with minimum of exposedmetal 2mm preferred . for this reasonSafety 2394 :
Caps: for megger 1552 .
Testprobes have removable Caps . “ reasons “ used for Live tests minimum ofexposed-metal 2mm preferred .
Tipsdo not exceed 4mm . Dead Tests .

 

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UsefulJunk : “ Making you Aware “

TestInstrument Manufactures will ( State ) to which Standards their Instrument(s)conform . BS-EN-61557

GN-3– 2011: Test instruments & Equipment . - Instrument Standard : Instrumentaccuracy % : ( Parts – BS-EN-61557-? )

BS-7671:2008:2011: to comply with Regulation . 612.1. (Testing )Measuring instrument & monitoring equipment & methods shall bechosen in accordance with the relevant (Parts – BS-EN-61557-? ) or if not . they must provide an equivalent of performance( BS-EN-61557 ) requires compliance with the ( Safety requirements ) of ( BS-EN-61010 )

BS-7671:2008:2011: does NOT require regular “ Calibration of Test Instruments “ However . inorder to maintain confidence in the ( Accuracy of the Test Instrument(s) forInitial Verification . & Condition reporting purpose . ( EIC ) & EICR )those ( Responsible for Testing ) should put in place an affective system toconfirm & record their continuing accuracy & consistency . so thatremedial action can be taken without delay if there is any indication that theinstrument is no longer sufficiently Accurate .

Itis important to be confident that the ( Test Instrument ) are accurate &remain consistent . Instruments ( May ) become inaccurate for a number of reasons.

Dowe take for granted the Test Instrument !! ( Abuse / Stress / Storage )

GN-3– 2011. Environment Condition(s) Why’s & How’s
Testers– has been designed to perform tests & measurements in a Dry-environment .( Basic-standards’ )
-Protective degree . IP-40 / 45
-Overvoltage . Test instruments must be of a category appropriate to the “Overvoltage’s “ likely to be Encountered
No we are not taking about the BS-7671:2008:2011 : here . ( Safe guards theOperator ) the Tester itself .
-Operating temperature ?? without moisture condensation ??

Incorrectmeasurement results . ?? How do we Know .
GN-3– 2011 . put the Question to Us .
Recognisable( Abuse ) to the Instrument due to ?? . Prolonged storage ?? . under Improperconditions .
Recognisable( Abuse ) to the Instrument due to ?? . Extraordinary transportation ( Stress )
□Many Instrument(s) are now provided with a cushioned box . to help them against( Mechanical Damage )
□Frequently transported from Site to Site . ( Abuse / Stress )

GN-3-2011 : p.82 .
Example. taking into Account Ambient environmental & usage factors as appropriate.
GN-3-2011 : Q) if an Instrument is leftin ( Storage ) at a constant temperaturein a Dry-environment for long periods ?? & is used Infrequently .
Ifan Instrument is roughly handled & is regularly transported & stored in( Vehicles ) how many times do we dump it in the Van . rushing to get home??

Service& Calibration .
Tomaintain the specified accuracy of the measurement results . the Instrumentmust be re-calibrated at regular intervals . either the Manufactures or anAuthorised dealer .
Recommenda re-calibration period of one year . am working of the Manufacturesinstructions .

 

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Low-résistance– Insulation résistance
GN-3:-2012 . Two or more of the functions of the above test instrument(s) MAY be combined in a Single-Instrument .