***Cont../ Useful Information for Electricians & Apprentices***

[amberleaf]

O.S.G.. The use of other methods’ of determining Maximum Demand is Not Precludedwhere Specified by the Installation Designer

FirstlyI make no Apologies for the Way am Writing on any Matters . it can be a first day Apprentice or some one Needing aJog of Memory .
Sowe are all in the Same Boat . “ To Learn “

For the Apprentices . The Day we stop learning is the Day we hang Upour Tool-Bag

CookerDesign Current Calculations

Thefirst thing you have to do is get Your Head around the Calculations !!

(From a Design point of View ) 2392-10

DomesticInstallation Oven(s) & Hob(s) are to be Calculated upon their MAXIMUM LOADING
Startwith a simple Calculation ( An Oven has a rating of 2kW ) 2000

(I = P/V ) Formula … I = 2000 ÷ 230V = 8.70A …. Weare Using the Unit Amps


2392-10/ Domestic Installation Oven(s)

Ovenhas 4 Rings ( 2 x 1kW ) & ( 2 x 1.5kW ) & Grill ( 2kW ) & Oven (3kW )

-Controlled via a CookerSwitch with a Socket outlet .

Asa Designer . we’ll have to Apply Diversity ??

Important )- Diversity allowance to be Applied to the FULL LOAD CURRENT for CookingAppliances .

TheO.S.G. is telling us . Purpose of the Final Circuit fed from theConductors )
O.S.G.Table 1B p/97 – column (3) Cooking Appliances → At the Top of the Page Note : Type ofPremises ( 2392-10 → Household Installations ) Domestic Installation(s)

DomesticInstallation(s) Only O.S.G. - 10A + 30% f.l – Full Load ) of connected Cooking Appliances in the Excess of 10A+ 5A if a socket-outlet is incorporated in the Control Unit . ( C.C.U. ) – 45A + 13A Socket Switched with Neon .

Fromyour point of View ( The First 10A ofthe rated current plus 30% of the reminder ( Plus) 5A if the Control Unit incorporates s Socket.

Calculations)- You bank “ Hold OFF“ the first 10 Amps of the Maximum Load Current )
The10A will be used at the End of the Calculations’

-So your Work out the Total Power Rating & then calculate the Full Load Current

Calculations)- Power = ( 2 x 1 ) + ( 2 x 1.5 ) + ( 2+ 3 ) = 10kW

I= 10000 ÷ 230V = 43.48A … round it up to the first four numbers43.47826087 ( 48 ) 43.48A

UsingDiversity allowance stated ↑↑ ( 43.48A sub 10A = 33.48A )

I= 33.48 x 30 ÷ 100 = 10.04A

Youradding the ( 5A ) for Socket outlet . I = 10A + 10.04 + 5A = 25.04A )- Asa Designer this is your Expected Current Demand .

Remember )- Supply Cables Rated to suit DesignCurrent ( Iz )

 

[amberleaf]

Scenario Only . This isonly an Example on the Wording that canbe Used :svengo:

-&-s. Section A . 2391-10 . :hurray:

Electricalinstallations require Inspection & Testing throughout their working life .

State( Three ) separate occasions when Inspection& Testing must be undertaken . Excluding Periodic Inspection .

New installations . additional work . alterations . minor works.

State( Three ) items of information that are required by a person undertaking the Inspection & Test ofan installation . Excluding information containedon diagrams . charts . or tables .

Maximum demand in amperes . number & type of live conductors. type of Earthing arrangement . thenominal voltage & frequency . prospective fault current & ( Ze ) external earth fault loop impedance . type& rating of the protective device .

State: the legal status for each of the following documents .

i)GS-38 / Non- statutory .
ii)GN-3 / Non- statutory .
iii)BS-7671 / Non- statutory .

State: Three different practical situations that may require the use of the sense oftouch during the Inspection process.

Feel for excessive heat from circuit breaker(s) or PVC/PVC .cable .
Feel for loose bolts connecting sections of cable trays .
Feel exposed bonding cable & clamps for ( Tightness )

List: Three items to be checked . as identified on the Schedule of Inspections .where fault protection is provided by automatic disconnection of supply ( ADS )

Check for presence of main bonding .
Earthing . circuit protective conductors .
choice & setting of protective devices .

 

[amberleaf]

State: Three requirements for test probes & / or lead as required by GN-38 . (2391-10 & 2392-10 here ) :hurray:

No more than 4mm exposed tip of probe 2mm – preferred .
Finger guards .
Fused test probe .
Leads long enough foe ( Safe Use ) leads in good order – No obviousdamage .

State: the correct instrument for conducting EACH ofthe following tests .

Continuity of the ring final circuit(s) – Low résistanceohmmeter . ( Ω )
External earth fault loop impedance on a ( TN ) system . Earth fault loop impedance tester .
Earth electrode résistance for a ( Generator installation ) . Earth electrode résistance tester .

Satewhy – for safety reasons .

a)Inspection must take place before testing (- Hazards such asexposed live parts . dangerous methods of erection & unexpected & dangerousenvironmental conditions .

b)BS-7671 identifies a sequence of tests tobe followed before the installation is Energised (- ifprotective conductor continuity is not confirmed then because this could be abreak or a loose connection there would be no point in insulation testing asthis would not go beyond the break

c)The installation polarity is checked when the supply is connected for the firsttime (- The supplier polarity could be reversed orthe electrician may incorrectly connect the tails ( in Reverse ) :svengo:

 

[amberleaf]

Statein the correct sequence the first FIVE teststhat would need to be undertaken on an ( A1 )Ring Final Circuit – during Initial Verification . :hurray:

GN-3 / p33 – 2.7.4.

i)Continuity of the protective conductors .
ii)Continuity of ring final circuit conductors .
iii)Insulation résistance .
iv)Polarity
v)Earth fault loop Impedance ( Zs )

Atthis point 2392-10 . You should get the book – GN-3 :bulb2:

( A1 ) O.S.G. – P/158

 

[amberleaf]

Rectification .

Apprentices. in the Regulation . Dead Testing

612.2.
612.2.1.
612.2.2.
612.3.
612.6 . By continuity methods

Testprior to the installation being Energised .

Sorryabout that my eyes get tired at thistime off night . Amber . ◄◄ :20:

Only when in Use . TT System .Earth electrode résistance . 612.7. ??

 

[amberleaf]

Part1

Important Announcement “ 2392-10 “ :46:
Goingfor your 2391-10 . is not a walk in the Park . It is not a Multi – Questions Testhere . I will Tax your Brain .

Mypoint of View here “ Amber “ . Getting a( Quick Fix ) does not help ( You ) in anyway to this Exam . 2391-10 .You have toStudy –BS-7671 / GN-3 :46:
Knowit inside OUT .

Whatis in a ( Question ??????? ) To many ( Implications ??????? ) jumpingover the garden wall . doesn’t mean it’s the shortest way .

State:

Two Test Methods to verify the continuity of the Protective Conductors . ( Question ) ◄◄
(- O.S.G. – p/80 . Three-steps Continuity of the Ring FinalCircuit Conductors . GN-3 – p36 .

Thisis a Quick Fix . ( Answers ) :20:
Method 1 (- Connect the Line ( R1to the CPC R2 at the distribution board ) measure résistance at the End of the circuit between( R1 & R2 ).
Method 2 (- Wander Lead method . ( R2 ) A → to → B . No breaks in cable / & theCable is Single . No / Parallel Paths .??

-&-sasked the ( Question ) Test Instrument to be Used to Conduct thisTest (- Low-Résistance Ohmmeter ) The correct Wording at all times . -&-s

Instrument(- Use a low-RésistanceOhmmeter for these tests – p/82 – 4.3. low-Résistance Ohmmeter

GN-3. The instrument used for low-Résistance Test may be either a Specialised low-Résistance Ohmmeter . or
TheContinuity range of an ( Insulation & Continuity Tester )◄◄ Wording . All in One Tester .

612.2.1 .
Thetest current may be ( D.C. or A.C. ) it is recommendedthat it be derived from a source with No-load voltage between ( 4V & 24V ) & ashort-circuit current not less than ( 200mA )

Instrumentsto ( BS-EN 61557- 4 ) will meet the above requirements .

 

[amberleaf]

Part2

SomeImplications . to Think about . Yeah :46:

Anyonecan make a mistake . even the most experienced of electricians . For this reason. all ( ElectricalInstallations ) alterations & additions should be Tested . Inspected& subsequently Certified ( Prior to handing over tothe Client for Use )

AsI have Explained this matter before . Reasons .
TheCertificate issued describes the ( Current Operating Parameters ) & will provide thebasis for any future alterations & additions to the Installation .

For-&-s point of View. You are giving a AccurateRepresentation of the Installation .
For-&-s point of View. The Test Instrument must . must be Accurate . (must be consistent )

 

[amberleaf]

Part3 .

Asa “ Inspector “

Thestart of your . Fundamental Principles . Requirements made in the Regulations . :hurray: :20:

BS-7671.Requires that every installation shall be ( Inspected &Tested ) to verify that the regulations havebeen met before being ( Put into Service ) following Regulations.

( T ) 134.2. Initial Verification. 134.2.1.
Duringerection & on completion of an Installation or an Addition or Alteration toan Installation . & before it is ( Put into Service) appropriate ( Inspection & Testing ) shall be carried out by ( Competent Persons ) to verify that the requirements of thisStandard have been MET .

( T ) 610. Initial Verification. 610.1.
EveryInstallation shall . during erection & on completion before being ( Put into Service ) be ( Inspected& Tested ) to verify . So far as isreasonably practicable . that the requirements of the regulations have been MET .

Precautionsshall be taken to avoid danger to persons & to avoid damage to property& installed equipment during ( Inspection & Testing )

( T ) 612. Testing . 612.1 InitialVerification .
Thetest of Regulations ( 612.2. to 612.13 )

612.2.1. – Continuity of the Protective Conductors’ ( Electrical Installations ) alterations & additionsshould be Tested . Inspected & subsequently Certified ( Prior to handing over to the Client for Use )

YourCertification . is your Compliance with Electricity at Work Regulation 1998 . ( ElectricalInstallations ) alterations & additions should be Tested . Inspected& subsequently Certified ( Prior to handing over tothe Client for Use )

Itis important that Electricians are not just able to ( Construct) They should also be able to ( Recognise ) Faults & take action .

-&-s. They are Asking the ( Big / Question ) Describe how to carry out ( CommonTests ) Soyou have to think like a Tester . at all times .
-&-s. Will be asking NEXT . Explain the NEED to comply with Test Values .

Itis Under Fault Conditions that Lives & Propertywill be at RISK . That’s why . BS-7671 Harp ON .

OldAmber is off on One AGAIN .

 

[amberleaf]

Am Sorry about the Break in the Forum . am having Problems with downloading . ◄◄◄

Iwill get Phil to down load something for me . tosee if its my Computer . ◄◄◄ :46: Amber

 

[amberleaf]

UsefulJunk .

BS-7671:2008.

Requiresthat the InstrumentsUsed for measuring Insulation Résistance mustbe capable of providing the Test Voltages stated

TestCurrent of ( 1mA ) instruments that are maintaining to ( BS-EN 61557) will satisfy the requirements ◄◄ What’s in a Number. Not a Multi/ Tester

It is Important that we read the Questions Carefully . -&- .We are all bad for not Look right . Yeah :46:

Insulation – Résistance . Ohmmeters .

Apprentices / Insulation Résistanceshould have a High Value & therefore InsulationRésistance Meters must have the Ability to Measure HighRésistance Readings .
TheTest Voltage - then you go to Table 61 . p/158

Apprentices / ( MΩ )

 

[amberleaf]

Every Cable has Résistance . :38:

Thisone always comes around . One way or Another.

State: the effect EACH of the following would have onthe measured résistance of a conductor .

Increasein length – Increase résistance .
Decreaseis CSA - Increase résistance .
Increasein temperature - Increase résistance .

2392-10. you will get this in Exams .

A Prospective Fault Current Test . is to be carried out on a Single-phase electricalinstallation . STATE .

a)The two Tests which are to be Undertake .

Testbetween the ( Line ) & ( Neutral ) for the maximum ( PSCC )

&between the ( Line & ( Earth ) for the Maximum ( PEFC)

b)Which value from ( a ) above will be Recorded asthe ( PFC ) The highest value above . ◄

the Highest Readingsfrom the Two Test . One or the Other .

Apprentices. if we look at BS-7671 . 612.11 ( Live Test ) ≈

Itwill tell you ( PFC) firstly . BUT they are TwoTests to perform . ≈

i) Prospective Short Circuit Current (- ( PSCC) Line &Neutral .

ii)Prospective EarthFault Current (- ( PEFC ) Line & Earth

2392-10 . ifyou have Measured . you do not need to Calculate. :dots: Yeah

Apprentices. . if we look at Regulations p/341 .

Certification& Reporting - Schedule of Test Results . ( PFC– kA ) :icon_bs:

ii)Prospective EarthFault Current (- ( PEFC ) Line & Earth . Example .
Typeof Supply . TN-S / TN-C-S / TT .
YourEarth External to the Installation - ( Ze ) ( PEFC ) Line & Earth .

Apprentices. With this Test . You are looking for Parallel Path(s) . Yeah Earthing . ◄ ≈ :mad2:

 

[amberleaf]

TTSystem . 2392-10 . Learning Curve . to becoming 2391-10. Q/As to be Had Here . ????? :earmuffs:

Iwill bring this to your Attention . the Importance of GN-3 ◄ :speechless:

AnEarth Electrode Resistance Test .
Isto be carried out using an EarthElectrode Resistance Tester . 2392-10 ( is it D.C. or A.C. ? )
Statethe recommended . ?? ( You want to belooking in GN-3 – p/46 / 47 )

a)Soil conditions during testing . GN-3 p/46 . Attheir driest . ( To Record highest Résistance ) ………….. GN-3 / During Dry Weather .
Regulations .542.2.2.
Thetype & embedded depth of an Earth Electrode shallbe such that Soil drying & freezing will not ( Increase) its résistance above the required value .

b)Distance between an Earth Electrode which is (3m in Length ) & the furthest Test Spike .GN-3 . P/46 . ( 30m)
c)Minimum number of Test Readings required . 3 readings &record the average . Fig – 2.6 / 3 xSpikes .

GN-3 . gives Solutions.

Oneway . ? p/47 . if the temporary spike résistance is too high . measures toreduce the résistance will be necessary , such as driving the spike(s) deeperinto the ground .

TestMethod 1 . Before this Test is Undertaken . the EarthingConductor to the EarthElectrode mustbe Disconnected either at Electrode or at the MainEarthing Terminal
Toensure that all the Test Current passes throughthe Earth Electrode ALONE.

-&-s. Switch OFFSupply before Disconnecting the Earth .
-&-s. AFTER completion of Testing ensure that the Earthing Conductor is Reconnected.

So. A Quick Fix to Answers are not Enough . Yeah .

Earth Electrode Résistance . Transformer ? Generator ? Test Method 1 BS7671 – Mobile or Transportable Units . Example

P47– GN-3 . Earth Electrode for RCDs . ( Questionsyou have to ask yourself ????????? ) Not a Quick Fix toAnswers . Only

Earth Electrode for RCDs
Ifthe Electrode under Testis being used in conjunction with a residual current device the followingmethod of Test may ( Be Applied ) as an (Alternative to the EarthElectrode Résistance Test )

Getyour GN-3 Book . Solutions :speechless:

Wherethe Electrical Résistance to Earth are ( Relatively High& Precision is Not Required )

AnEarth Fault Loop Impedance Tester may be USED . ETC

GN-3 – ( Alternative for RCD protected TT /Installation ) Method2 . p/48

2392-10. A Loop Impedance Tester .is connected between the Lineconductor at the SOURCE of the TT /Installation & the Earth Electrode .

From-&-s point of View . The Impedance Reading taken is Treated as the Electrode Résistance .

AsGN-3 rightly put it . / Values above 200Ωmay not be stable . as Soil Conditions Changedue to FACTORS such as Soildrying & freezing .
:angelsad2:

 

[amberleaf]

Test Method 1 :

Uses the Line as areturn Lead . Otherwise known as . ( R1 + R2 ) Method

Most Common Method usedfor ( Final Circuit(s) …. Point to Note . Wording( Final Circuit(s) / Radial(s) / RingFinal Circuit
Line conductorruns alongside a Protective conductor .

Instrument to be Used . ( Low-résistance-ohmmeter )

Some Wording for -&-s . ( Low-résistance-ohmmeteris then connected at the Most / FurthestPoint of the Circuit . & a Readingis Obtained )
This Readingof the Line Conductor & the Protective Conductor & is given the Name ( R1 + R2 )

Sate : The scale to be Used . ( Ω )

Record ( R1 + R2 ) on the Schedule of Test Results .

Advantages ( R1 + R2 ) readings can be used forworking out Our Earth Fault Loop Impedance Value ( Ω ) . ifwe decided NOT to measure it .
Advantages ( R1 + R2 ) Polarityof the circuit is also Obtained at the Same Time

Advantages ( R1 + R2 ) Polarity( By Continuity Methods ) :rockon:

 

[amberleaf]

Useful Junk .

“ Earth Résistance “is the Résistance of soil to the passage of Electrical Current .

“ Earth “ is arelatively poor conductor of Electricity compared to Normal Conductor(s) likeCopper . :dots:

Practical “ Earth Electrode“ that provides a ( Low-Earth-Résistance )is not always easy to Obtain .

State : When you find that your Earth Electrode resistance is NOT Low-enough . there are several ways you can improveit .
State : Two methods .

•lengthen the Earth Electrode in the Earth .
• Use multipleRods .

( R ) Résistance ( a ) is the cross-sectional-area of the path … (Ra ) . PS. This is my Own Conclusions . Amber . :icon_bs:

17[SUP]th[/SUP] Edition .

( Ra ) is the SUM of therésistance of the Earth Electrode & the Protective Conductor connecting it to the ( Exposed-conductive-parts) in Ohms .

 

[amberleaf]

Two Methods are given in IEE Guidance Note 3 …. ( TT Systems )

Inspection & Testing for measuring the ( Résistance of Installation Earth Electrodes )

Test Method 1 . Before thisTest is Undertaken . the Earthing Conductor to the Earth Electrodemustbe Disconnected either at Electrode or at the Main Earthing Terminal
Toensure that all the Test Current passes through the Earth Electrode ALONE.

Test Method 1 :

Which ( ONLY ) the ( Résistance ) of the Electrode & the Earthingconductor connected to it are Measured .

Used where a ( High Level ofAccuracy ) & where Low Valuesof Electrode Résistance to Earth are Required .

Test Method 1 :

Involves the Use of a ( ProprietaryTest Instrument )
Regard to Electrode TestInstruments . ?? Proprietary make of Instrument with a ( Three or Four) Terminal arrangement should be used in order that the résistance of the Test leads& Test Electrode may be Evaluated . ( D.C. ) batteries or rechargeable .

How to Remember (- TT Systems - Test Method 1: ←→ ( Résistance ) :6: :willy_nilly:

 

[amberleaf]

Two Methods are given in IEE Guidance Note 3 …. ( TT Systems )

How to Remember (- Test Method 2: ←→ ( Impedance ) :6: :willy_nilly:

Test Method 2 :

Which the ( Impedance )of the ( Whole Earth Fault Current Part is Measured )

& is taken to be the ( Résistanceof the Electrodes ) This Method is Used. ( High Level of Accuracy is NOT StrictlyRequired ) ◄◄ :6:

Test Method 2 : ▼▼▼
Involves the use of a ( EarthLoop Impedance Tester ) GN-3

 

[amberleaf]

2392-10 : Division of Installation .

If we look atRegulation 314.1. :coolgleamA:

The Choice is Your as Designer(s) .

314.1 . does not mention . Thata Ring Final Circuit should be the Automatic Choice for Socket – outlets

• Ring Final Circuit .
• Radials

 

[amberleaf]

Apprentices

Important to remember that where a Residual Current Device does not ( Incorporate OvercurrentProtection ) A Circuit Breakermust be Used . :gettree:

 

[amberleaf]

Something I knocked up . ( PIR ) one day ??

Regulations . 612.2.1. ( R2 ) Continuity of ProtectiveConductor(s) . :banghead:

Apprentices .

There’s to much writtenabout Ring Final Circuits . Method 1

Method 2 (- usesthe Wander Lead or ( R2 ) Method

Mainly used on MainProtective Bonding Conductor .

Reason : You must Confirm the Continuity of Main Protective Bonding Conductor . ( A ◄► B )

Firstly : Permission beforehand as this may have SafetyImplications . “ IMPORTANT “

i) Safe Isolation . before you begin .
ii) Disconnect any Parallel Paths . This can be done byDisconnecting ◄► MainProtective Bonding Conductor . from the ( MET)
iii) Disconnecting ◄► MainProtective Bonding Conductor . from BS-951/ Earth Clamp .

-&-s . Null the leads . Why ?? . Wander Lead will add aconsiderable résistance to your Instrument .
-&-s . Instrument does NOT have a Null function . Subtract the résistancefrom the Actual Reading .

-&-s . Readingcan be recorded as the Résistance of the ( CPC / R2 ) on the Schedule of Test Results . Example .Regulation . p/341 . Continuity ( R2 * / Ω ) Dead Test

Remember (- -&-s . to Reconnect Parallel Paths . )

-&-s . Earthing Clamps must conform to BS-951 / “Safety Electrical Connection – Do Not Remove “ Etc

Remember . Anything to do with Earthing . -&-s are allover you like a Bad Rash . Yeah :gettree:

 

[amberleaf]

Apprentices : amUsing the Wording to help you Understand someConcepts of Earthing . Regulation .P/32 . fig2.1 :26:

From the ( Service Cut-out ) 16.0mm[SUP]2 [/SUP] → Earthing Conductor to the → ( MET ) → 10.0mm[SUP]2 [/SUP] → Gas / Water (- MainProtective Bonding Conductor .

Safety EarthConnection . Do Not Remove .

TT System (- EarthingConductor from the ( MET ) → Earth Electrode .
TT System ( MET ) → 10.0mm[SUP]2 [/SUP] → Gas / Water (- MainProtective Bonding Conductor .

541.13. Warning Notices : Earthing & BondingConnections

SafetyElectrical Connection . Do Not Remove .

 

[amberleaf]

Final Circuit for Lighting . Loop-in method is Usedfor wiring a ( Final-Circuit ) for Lighting . :thinking:

 

[amberleaf]

The Magnetic Mechanism usesa solenoid with an Iron piece . Etc .Used for ( Short-Circuit Currents / Fault Protection )

• Thermal Mechanism .
This mechanism uses a ( Heat Sensitive Bimetal Element) it is Used for ( Overload Circuit Protection )

Advantages . Immediate indication of ( Fault Current) by Identifying which circuit the ( Fault )occurred on
Advantages . Reclosing can be Effected at Once after the ( Faulthas been Cleared )

 

[amberleaf]

Apprentices : Learning Curve . Point to Note :

RCDs . Because the RCD trips in milliseconds ( mS ) 30 / milliamps. ( mA )

Regulation . Definitions – p/29 ( RCCB ) :speechless:

• The Short Circuit doesNOT Produce an Imbalance between the Line & Neutralcurrents in the ( RCCB ) They are still out there on the 16[SUP]th[/SUP]Edition .
• The ( RCCB ) does Not Incorporate an OverloadFunction .

UsefulJunk :

MCB – The difference being it has Three-States in can be . ( OFF) → ( ON ) → ( Tripped )
CircuitBreaker : is designed with a ( Switch ) in orderto Turn a Circuit – ON / OFF .

(can be used for Isolation / FunctionalSwitching ) Table 53.2.

 

[amberleaf]

Miniature Circuit Breaker . ( MCB) :earmuffs:

AdvantagesCan operated by Hand or Automatically .

• The Automatic Operationis done by Using . Magnetic or Thermalmechanism

 

[amberleaf]

Thisis a Sub-Board . ( Main Board is Isolated / LockedOFF ) :speechless:

ThisTest in done on the 16[SUP]TH[/SUP] Edition ( No- RCDs ) … Just Main Switch 100A . Example

Insulation Résistance Test (IR )

Example(- 6 / Way

ThirdTest:

Dead Test /Safe Isolation procedures should be carried out . Priorto Testing

Thiscan be carried out at the Main Switch ( 100A ) at the Distribution Board . being Tested

Youmust Insure that the ( Switch ) in the ( On-position ) with allthe ( Circuit breaker(s) for all circuits to be Tested .

indoing this . ( You must Insure that – all Lamps / Dimmer switches or Appliancesare RemovedPrior toTest

theTest is carried out between the ( Line & Neutral ) Usingan Insulation Résistance Tester / set on( 500V / MΩ. Scale )

•500V Scaleis Applied / A reading should be Greater that (≥ 999 . is Obtained )
TheTest is then carried out On .

theTest is carried out between the ( Line & Earth ) Using an InsulationRésistance Tester / set on ( 500V / MΩ . Scale )
•500V Scaleis Applied / A reading should be Greater that (≥ 999 . is Obtained )

TheTest is then carried out On .

theTest is carried out between the ( Neutral &Earth ) Using an InsulationRésistance Tester / set on ( 500V / MΩ . Scale )
•500V Scaleis Applied / A reading should be Greater that (≥ 999 . is Obtained )

Thisproves that the ( Line & Neutral ) arenot Touching .
Thisproves that the ( Neutral & Earth )arenot Touching .
Thisproves that the ( Line & Earth ) are not Touching .

(No Breakdown of the a ConductorInsulation ) -&-s

MCBs/ Red or Green indicator provides Immediate Visual Indication of Devices
ForIsolation Functions (- Green / OFF . Red / ON .

 

[amberleaf]

Inspection& Testing , before an Installation is Fully Commissioned is a Critical Task. :53:

“ Visual &Testing “
:juggle2:
Apprentices & 2392-10 . Ring Final Circuit .

This is just the same as if you where doing it onConsumer Unit ( DEADTEST )

On Industrial Premises’ .

When doing Insulation Resistance Testing on a Ring Final Circuit it have to “ Be “ Individually . ( IR ) as it is NOT Possible to carry out InsulationResistance on Industrial Installation as a Hole ’ . Yeah

Firstly . Ring Final Continuity Checks .

This is done by disconnection of Both Ends of the Line ( Neutral &Circuit Protective Conductor ) from the Board.

Continuitycan be Checked for Each Conductor .

Check : Null out yourLeads / Megger 1552 .

Step - 1. Line to Line . 0.26Ω . ( Lower )
Step - 2 . Neutralto Neutral . 0.26Ω . ( Lower )

Step – 3 . CPC to CPC . is aReduced Cross-Sectional Area its Résistance . ( Which then is “ Higher “than the Phases0.33Ω .) being/ Line / Neutral

Next Step .
( DB ) “ Distribution Board “Cross/ Connect . Neutral to Line. Vice. Versa
( DB ) “ Distribution Board “Cross/ Connect . Line toNeutral

The Résistance of the ( Line& Neutral Résistance at any SocketOutlet ) Readingshould be the Same . ? 0.15Ω

• IndustrialInstallation / Wired in Single(s) Core Cables “ Same Size “ ???
• If Readings ( Increase ) from point of supply . You may have ( Mixed ) up the Line& Neutral Conductors . off the Two Legs of the Ring .

Double Check (- The Readings should be ??

Line :0.26Ω
Neutral: 0.26Ω + ( 0.26Ω + 0.26Ω = Combined 0.52Ω )

¼ Combined : 0.13Ω

“ Spurs “ will give a SlightlyHigher Reading(s) it will give the Résistance of the Spur Conductors’ .

Next Step . ( Final )
( DB ) “ Distribution Board “Cross/ Connect . Lineto CPC . Vice. Versa … Readings / ( R1 + R2 )
( DB ) “ Distribution Board “Cross/ Connect . CPCto Line .

The Résistance of the ( Line& CPC Résistance at any Socket Outlet ) Readings / ( R1 + R2 ) Polarity checked at this Stage . as well as Visual Inspection on Terminals .

The reading should be the Same ( ¼ Combined Résistance : ofthat of the Line &CPC .
Spurunits will be Slightly Higher .

The Highest Reading Obtained . will be Recorded . ( R1 + R2 ) Schedule of TestResults. ( Line / 0.22Ω + Neutral / 0.23Ω) R2 – CPC /0.3 . ( R1 + R2 ) 0.52Ω

Whilst the Ring Conductors are Disconnected it make sensethe do Insulation Résistance Test . at this Point .

 

[amberleaf]

2392-10 / Some Regulation for Installing a ConsumerUnit : The WHY.S :speechless:

416.2. - Note : Barriers or Enclosures are Intended to prevent ( Contact with Live Parts )

(- Cable Entry Sealed to ( IP4X ) 416.2.2.Horizontal Top Surface of a Barriers or Enclosures .

(- Enclosures Sealed to ( IP2X i.e. BLANKS FITTED )

ii) After disconnection of the Supply to ( Live Parts ) againstwhich the Barriers or Enclosures afford ( Protection ) Restoration of theSupply being possible ( ONLY ) after
replacement orReclosure of the ( BARRIER or ENCLOSURES ) Etc .

(- Sufficient Space to allow Cables to Bend into Devices .
MechanicalStresses . 522.8.3.
The ( Radius ) of every ( Bend ) in a wiring systemshall be such that conductors or Cables do not suffer ( Damage & Terminals are NOT Stressed )

Plain English(- Such that Conductors’ & Cables shall NOTsuffer Damage )
:13:
This is Whatyour Assessor is Looking for . - (- Cables Sheaths NOT stripped Outside ofEnclosures . 526.9.

Cores of ( Sheathed Cables ) from whichthe Sheath has been Removed & Non-sheathed cables at the termination ofConduit . Ducting or Trunking shall be Enclosed as required by Regulation .526.5.

(- EnclosureMaterialAppropriate to the Environment . 522.6.1.
Wiring Systemsshall be selected & Erected so as to Minimize Mechanical Damage . e.g. .damage due to Impact . Abrasion . Penetration . Compression or Tension . DuringInstallation .

( T ) (- Diagrams “ must be Provided .514.9. / 514.12.1.
A legibleDiagram . Chart or Table or equivalent form of information shall be providedindicating in particular . ( Circuit Detail Labels )

(- Unit Adequately Fixed . 416.2.3.
A Barrier orEnclosure shall be Firmly Secured in Place . ETC

Division ofInstallation . 314.1.
InstallationCircuit Arrangement . 314.4.
Protected byAppropriate Devices . MCBs – 433.1.1. / Protection by One Device ( iii )

514.8.1.Identification of a Protective Device : MCB .
A ProtectiveDevice shall be arranged & Indentified so that the Circuit Protected may beeasily Recognised .

511.1 ) Complieswith the relevant requirement of the applicable British Standard / Harmonised Standard .
510.2. ) ManufacturesInstructions are followed .

TheProtective Devices in the Consumer Unit are adequate for the Prospective FaultLevel . Conditional rating . ??
313.1/ 512.1.2. ( ii )

TheRating of the MainSwitch or Circuit Breaker is sufficient for the Likely Electrical Load .512.1.2. ( i )

The( Tails ) between the Consumer Unit & the (Meter ) → or DNO / Isolating Switch . ( Note– An Isolator is often Not Installed bythe Distributor ) O.S.G. p/15
Adequately( Sized ) & Protected against Mechanical Damage .
523.1. )
522.6.1) AG
522.8.1.) AJ .
433.1.1.)

 

[amberleaf]

FirstAmendment - Deleted by BS-7671:2008 . Conduit/ 514.2.1. :50:

Orange as a means of identification of an electrical conduit has beendeleted

 

[amberleaf]

( If ) / FaultCurrent ( A ) Example : V / Z – 230V ÷ 0.32Ω = 718.75A . :gettree:

 

[amberleaf]

Wire Résistance :

What affects the Résistance of a Wire . :15:
Answer : ConductiveElectrons moving through thewire bang into Electrons attached to Atoms . “ Facts “ This converts some ofthe Electrical Energy to Heat .

The effects the Résistance in Wires :

Length :
Cross-sectional area :
Material : ! Copper .
Temperature : °C

 

[amberleaf]

Electrical Connections - Regulations. 526.1

Conductor terminationsare properly secure ( Tight ) withintheir terminals :speechless:

 

[amberleaf]

Apprentices :

RCDs / are NOT designed to break the ( High ShortCircuit Currents ) Which may Occur in Domestic Wiring Installations &must be Used with an Over-Current Protection Device “ Such as MCB “

RCD reacts to currentleaking from Line to Earth & an MCB reacts to Excessive Current . :icon14:

RCCBs . Residual Current Circuit Breakers /Which provide Earth Fault Protection only .
RCBOs . Residual Current Circuit Breakers / WithOverloadProtection : Which provides Earth Fault . Overload & Short-Circuit Protection

Apprentices : What is an RCBO - RCD / MCB .
RCD – Side Earth Fault . reactsto current leaking from Line to Earth / Faults

RCBOs . if welook at an ( RCBO ) B / Curve 30mA
RCBOs . if welook at an ( RCBO ) C / Curve 30mA

RCBOs .Respond to both ( A.C. ) & Pulsating ( D.C..) Residual Currents &are Manufactured to Comply with BS-EN 61009-1

Manufactured(- The Single Module ( RCBO ) is an Electronic Unit designed specificallyfor fitting into ( Plastic & Metal ) & Distribution Boards to give ( Earth Leakage Protection ) to an IndividualCircuit .
:earmuffs:

 

[amberleaf]

2392-10:

UsefulJunk . RCBO. :speechless:

Thethin white wire ( Earth Cable ) is purely there as a ( Back Up ) incase of a Loss of Neutral .

The Good News . Unfortunatelyits Not Possible to ( Disable ) or ( By-pass ) the RCD functionon a RCBO .

 

[amberleaf]

2392-10 Practical Assignment ( -&-s Exam : To be Used only for MinorElectrical Work which ( Does Not ) include the (Provision of a New Circuit ) :53:

2392-10
Completionof Minor Electrical Installation Works Certificate .

The Minor Works Certificate is intended to be Used for Additions & Alterations toan installation that Do Not extend to the provision of a New Circuit .
ThisCertificate may also be Used for the Replacement of Equipment suchas Accessories or Luminaries.

2392-10 p/336 .
Appropriate Inspection & Testing . should always be carried out ( Irrespective ) of the extent of the Work Undertaken .

• Part / 1 : Description of Minor Works .
( 1 / 2 ) The Minor Works be so described that the workthat is the subject of the Certification can be ReadilyIndentified .
1) Description of the Minor Works .
2)Location / Address .

4)Regulation ( 120.3& 120.4 ) Nodepartures are to be ( Expected Except in most UnusualCircumstances ) Regulation 633.1.
Part4 (- I/We Certify that the said works donot impair the safety of the existing installation . Etc .

• Part / 2 : InstallationDetails .

2) The method of FaultProtection must be clearly indentified .
“ System “ Earthing Arrangement. TN-C-S . TN-S . TT .
Automatic Disconnection of thesupply using ( Fuse . Circuit/Breaker . RCD .

4)if the Existing Installation ( LACKS ) either aneffective means of Earthing or Adequate Main Protective Bonding Conductor . this must beclearly stated . Regulation . 633.2.
EarthingConductor : Distribution / MET – 16.0mm[SUP]2 [/SUP] ???
RecordedDepartures from ( BS-7671:2008 ) May constitute( Non-compliance) with the Electricity Safety . Quality & Continuity Regulations 2002 ( asamended ) or the Electricity at Work Regulation 1989 .

2392-10 as a Tester .
It is Important that the client is Advised Immediately in Writing .

Commentson ( Existing Installation ) including adequacyof Earthing & Bondingarrangements . Regulation 131.8 .

• Part / 3 : Essential Tests )

Therelevant provisions of ( Part 6 ) Inspection & Testing of BS-7671:2008 / Red cover .

Mustbe Applied in Fullto all Minor Works .
• Here’s you Example . Where aSocket outlet is added to an Existing circuit it is Necessary to . ??

i)Establish that the Earthing Contact of the Socket outlet is connected to the ( Main Earthing Terminal )
ii)Measure the ( Insulation Résistance ) ofthe circuit that has been added to . & establish that it complies with ( Table 61 of BS-7671:2008)
iii)Measure the ( Earth Fault Loop Impedance ) toestablish that the Maximum permitted Disconnection Time is NOTExceeded .
iv) • Here’s you Example . )- Check that the Polarity of the Socket outlet is Correct .
v)if the Work is Protected by an ( RCD ) verifythe Effectiveness of the ( RCD )

• Part / 4 : Declaration .

1/ 3 ) : The Certificate shall be madeout & signed by a ( Competent Person ) I respectof the Design . Construction . Inspection & Testing of the Work .
1/ 3 ) : The ( CompetentPerson ) will have a sound knowledge & experience relevant to thenature of the Work undertaken & to the Technical standards set down in ( BS-7671:2008) be fully ( Versed in the Inspection & TestingProcedure ) contained in the Regulations &Employ adequate ( Testing Equipment )

2)When making out & signing a form on behalf of a Company or other Businessentity . State for whom they are Acting. :34:

 

[amberleaf]

2392-10:
DirectMeasurement of ( Zs ) can only be made on a LiveInstallation . ( Live Test ≈ ) :speechless:

Neitherthe ( Connection ) with Earthnor Main Bondingconductors are ( Disconnected ) The reading given by the ( Loop Impedance Tester ) will be Less than ( Ze) + ( R1 + R2 ) because of ) Parallel Earth Return Pathsprovided by any Bonded Extraneous-conductive-parts.

 

[amberleaf]

TheExternal Impedance ( Ze ) be measured using (Earth Loop Impedance Tester ) :svengo:

TheMain Switch is opened & made secured to disconnect the Installation fromthe source of supply .
The( Main Earthing Conductor ) is disconnectedfrom the ( Main EarthingTerminal ) & the measurement made between( Line ) & ( Earth) of the supply .

Pointto Note : ( Ze ) is Measured using an Earth FaultLoop Impedance Tester at the ( Origin of the Installation )

Pointto Note : GN-3 : ( 3) p/50
542.4.2.(- The impedance measurement is madebetween the Line of the Supply& the means of Earthing with the ( Main Switch Opened ) OR
Withall ( Circuits Isolated )

From-&-s point of View .
Careshould be Taken to Avoid any Shock Hazards’ to the Testing Personnel & otherspersons on both whilst establishing contact .

Note : -&-s (- Parallel Paths . Yeah . 610.1. :nono:
Note : -&-s (- Themeans of Earthing must be DISCONNECTED from theINSTALLATION Earthed Equipotential Bondingfor :nono:
Note : -&-s (- Ensurethat the EARTHING CONNECTIONS has been REPLACED before RECLOSINGthe MAIN SWITCH . ◄◄ :nono:

 

[amberleaf]

2392-10 Practical Assignment ( The Regulation are Reinforcing this Matter ) Not – Energised Yet ) Dead / Testing . :hurray:

2392-10: Notes on Schedule of Test Results . p/341 . Learning Curve . :46:

1)Type of Supply isascertained from the distributor or by ( Inspection)
2)( Ze ) at origin .
Whenthe maximum value declared by the Distributor is( Used ) the effectiveness of the Earth must be Confirmed ( Bya Test )
Ifmeasured the MainBonding will need to be ( Disconnected )for the Duration of the Test. ◄► ( ONLY )

3)Prospective FaultCurrent ( PFC )The value ( Recorded ) is the Greater of Either the ( Short-Circuit Current ) OR
TheEarth Fault Current ( The Highest on the Schedule of Test Results ) -&-s . 2392-10 . Exam :driving:

4)Short-circuit capacity of the device is noted .

( T ) The following Tests . Where relevant . shallbe carried out in the following sequence .

612.2.1. Continuityof Protective Conductors . including Main& Supplementary Bonding . ( When Required ) Etc
-&-s. Every Protective Conductor – should be Tested to verify that it is ( Continuous& Correctly Connected )

6)Continuity :
Where( Test Method 1 ) ◄► is Used enter the MeasurementRésistance of the Line Conductor plus the ( Circuit Protective Conductor ) - ( R1 + R2 ) look. GN-3
Duringthe Continuity Testing ( Test Method 1 ) ◄ The following ► ( Polarity Checksare to be Carried OUT )
( Polarity / i) Every fuse & single-pole control &protective device is connected in the Line conductorONLY . ► ( 612.6. )
( Polarity / ii) Centre-contact bayonet & Edison screw lampholders have outer contact connected tothe ( Neutral Conductor ) ► ( 612.6. )
( Polarity / iii) Wiring is correctly connected toSocket Outlet & similar accessories . [ Compliance is to be Indicated by a ( Tick )column / 11

( R2 ) is recorded in Column 7 . ( I put this in for Apprentices / ( PIR ) Wander Leads . Methods . 612.2.1.

Where( Test Method 2) is used . The maximum values of ( R2 ) isrecorded in column 7 . ( Get yourself acopy of GN-3 ) it Helps a Lot .

8)Continuity of the Ring Final Circuit Conductors . 612.2.2.
A testshall be made to ( ►Verify ◄ ) the Continuity of ( EACH) conductor including the ( Protective Conductor) of every Ring Final Circuit .

► 9) 10 ) Insulation Résistance .( IR )
Allvoltage ( Sensitive Devices ) to be Disconnected ◄◄612.3.3. plus – Note
Ortest between ( Line & Neutral ) connected together & Earth . TheInsulation Résistance between ( Live Conductors ◄►) Column 9 / Line / Earth – 10

 

[amberleaf]

WordingRectified ( Sorry) ◄◄◄ :rolleyes2:

2392-10 Practical Assignment ( The Regulation are Reinforcing this Matter ) Not – Energised Yet ) Dead / Testing . :juggle:

( T ) The following Tests . Where relevant . shallbe carried out in the following sequence .

612.2.1. Continuityof Protective Conductors . including Main& Supplementary Bonding . ( When Required ) Etc
-&-s. Every Protective Conductor – should be Tested to verify that it is ( Continuous& Correctly Connected )

6)Continuity :
Where( Test Method 1 ) ◄► is Used enter the MeasurementRésistance of the Line Conductor plus the ( Circuit Protective Conductor ) - ( R1 + R2 ) look. GN-3
Duringthe Continuity Testing ( Test Method 1 ) ◄ The following ► ( Polarity Checksare to be Carried OUT )
( Polarity / i) Every fuse & single-pole control &protective device is connected in the Line conductorONLY . ► ( 612.6. )
( Polarity / ii) Centre-contact bayonet & Edison screw lampholders have outer contact connected tothe ( Neutral Conductor ) ► ( 612.6. )
( Polarity / iii) Wiring is correctly connected toSocket Outlet & similar accessories . [ Compliance is to be Indicated by a ( Tick )column / 11

( R2 ) is recorded in Column 7 . ( I put this in for Apprentices / ( PIR ) Wander Leads . Methods . 612.2.1.

Where( Test Method 2) is used . The maximum values of ( R2 ) isrecorded in column 7 . ( Get yourself acopy of GN-3 ) it Helps a Lot .

8)Continuity of the Ring Final Circuit Conductors . 612.2.2.
A testshall be made to ( ►Verify ◄ ) the Continuity of ( EACH) conductor including the ( Protective Conductor) of every Ring Final Circuit .

► 9) 10 ) Insulation Résistance .( IR )
Allvoltage ( Sensitive Devices ) to be Disconnected ◄◄612.3.3. plus – Note
Ortest between ( Line & Neutral ) connected together & Earth . TheInsulation Résistance between ( Live Conductors ◄►) Column 9 / Line / Earth – 10

 

[amberleaf]

Polarity: Red Cover .2008 .

A SatisfactoryPolarity Test . may be indicated by a Tick incolumn 11 . – p341.

( PIR ) / 2391-10(- Only in a Schedule of Test Results associatedwith a ( Periodic InspectionReport ) is it acceptable to record IncorrectPolarity .

2392-10. When your doing a New Installation / Initial Verification . you have Checked Anything. New Design . Yeah . :13:



Polarity: Red

 

[amberleaf]

FunctionalTesting . ?? :13:

TheOperation of RCDs . & RCBOs shall be tested by Simulatinga Fault Condition .

i)Independent of any Test Facility in the device .Record operating time . column 13. RCDtime . x1 / mS
ii)Effectiveness of the Test Button must beConfirmed . GN-3

FunctionalTesting ?? . 14 . Other . x5

 

[amberleaf]

:leaving:2391-10:

14. All switchgear & Controlgerar Assemblies . Drivers . Control & Interlocks .
Mustbe operated to ensure that they are Properly Mounted . Adjusted . &Installed .

Satisfactoryoperation is Indicated by a TICK . column 14