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

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2392-10: :aureola:

Statethree different types of Protective Conductorthat are commonly connected to the Main Earth Terminal ( MET ) of an Electrical Installation .

i)Earthing Conductor .
ii)Circuit Protective Conductor .
iii)Main Protective Bonding Conductor .

 

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Self-employed Electricians going to working in Industry . :crazy:

The Pop Up machines now come under the ( PAV ) Category ( Push Around Verticals )

Which also includes the ( 1a ) Category .This course can be done solely for these .

But be more advantageous for you to dothe ( 3a ) Category ( Scissor Lifts ) whichwould also cover you for using the ( PAVs ) and any in the ( 1a ) Category . proving that you have had “Familiarisation “ on them .

What your needing . ( PAL ) Powered Access Licence .
Type ( 3a / 3b ) ◄◄

IPAF : ( 1 person ) One Day Course .Training £ 228.00 – Vat paid

Lasts : 5 Years .

This will show you the Machines to Use . WWW.ipaf.org

 

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FourDocument that the ( Inspector ) may need to consult during the Inspection& Testing procedures . :vanish:

BS-7671:2008.
IET– Guidance Note – 3
IET– On – Site – Guide .
TheElectricity Safety Quality & Continuity Regulations 2002 .

 

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Inspection& Testing of Electrical Installations . :vanish:

Usingdiagrams to support your answer explain the three steps required to perform aContinuity of Ring Final Circuit Conductors Test.

Explainany precautions & checks you would make before starting the Test .

Using (- A Low résistance ohm-meter continuity tester will beused for this Test .

WithTest Leads & Probes conforming to HSE . GN-38
Beforeany measurements are taken the résistance value of the Test Leads .
&Probes are noted & this value is subtracted from any Test Results . Alternatively if the Test Instrument has anAuto null facility this should be applied before any measurements are recorded.
Withthe electrical installation safety Isolated& Proved Dead.

Indentify& disconnect the Line . Neutral . & CPCconductors of Ring Final Circuit at the Distribution Board .

Measure& Record the End to End résistance of the following.

Therésistance of the Phase to Line Loop = (r1 )
Therésistance of the Neutral to Neutral loop = ( r/n )
Therésistance of the CPC to CPC loop = ( r2 )

Thevalues of ( r1 + r/n ) & r2 willindicate whether the conductors are continuousor not .

A FiniteSmall reading will indicate the conductors are continuous .

A high Résistance value will indicatethe conductors are Open Circuit . or Faulty . orConductor terminations are loose .

TheLine & Neutral conductors both being typically 2.5mm[SUP]2 [/SUP] should have equal values of résistance:- Measured within 0.05Ω of each other .within 0.05Ω
Wouldalso apply if the Ring Final Conductors were larger ( 4.0mm[SUP]2 [/SUP] ) CPC being 1.5mm[SUP]2 [/SUP] . for
2.5mm[SUP]2 [/SUP] / 1.5mm[SUP]2 [/SUP] T&E - has a smaller Cross-sectional area than theLine 2.5mm[SUP]2 [/SUP] conductors . As suchthe CPC résistance will slightly higherthan the Line conductors’ .

2.5mm[SUP]2 [/SUP] / 1.5mm[SUP]2 [/SUP] T&E - The résistance of the CPC should beapproximately ( 1.67 times ) greater than the résistance of the Line conductors.
Performa quick calculation to check the Expected value of the CPC is approximately ( 1.67times ) larger than the Line Conductors .

 

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Whattype of Inspection & Tests . Will be required for the ElectricalInstallation within this building . ??

Forthe ( NEW ) Electrical Installation . an InitialInspection Test & Verification
Forthe ( Existing ) Electrical Installation . anPeriodic Inspection report & Test .

Listall the relevant documentation that need to be competed for this ElectricalInstallation . ??

( 2392-10 ) ► New ◄ Electrical Installation
i)Electrical InstallationCertificate .
ii)Schedule of Inspections .
iii)Schedule of Test results .

thistake you into 2391-10 ) ( Existing ) Electrical Installation
i)Periodic Inspection Report for an Electrical Installation
ii)Schedule of Inspections .
iii)Schedule of Test results .

 

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Twopossible conditions that may have an Effect on the Measured value of ( EarthFault Loop Impedance ) :vanish:

i)Ambient Temperature in the locality of thecables Under Test .
ii)The Actual Temperature of the Cables Under Test .

 

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Whatfunction does a Switch perform in the Circuit . :willy_nilly:

ASwitch ( Opens ) or ( Closes) an electrical circuit .

Ifthe Circuit is ( Open ) – NO electricityflows . “ Circuit is broken “

Ifthe Circuit is ( Closed ) - Electricity Flowsthrough the Circuit . 2392-10 ( Can we confirmPolarity ) “ Circuit is complete “

Sowhat is a Polarity Test .

Basicallyit is a Test that creates a Circuit using the Line conductor & the singlepole device in question . Breaking the circuit when Operating the device . means that the reading on theInstrument will Change .

&thus confirming that device must be connected in the Line Conductor .

Test to Ensure that all singlepole devices ( Fuses . Switches . & Circuit Breaker ) are connected inthe Line Conductor Only .


Switch: Permanent Live. Switch Live .

Switching T&E . You should sleeve the Blue Conductor / with brown sleeve .to say it is being used as a Switch Wire .

UsefulJunk .

Metal is Used in Switches because most Metals are Good Conductors of “ Electricity “

 

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DomesticInstallation

Whatis - Circuit Control from a Testers point of View ? :willy_nilly:

Itis Vital that any Circuit . NO matter its levelof complexity . ( Can be Controlled )

Asimple Switch :- allowing us to turn the CircuitOn or Off .

 

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Regulation/ Definitions – p/26 . Wording

Isolation :- “ Function “ .

Afunction intended to Cut Off for reasons of safety the supply from all . or a discretesection . of the Installation by separating the Installation or Section fromevery source of Electrical Energy .

Isolator :- “ Disconnector “

AMechanical Switching Device which . in the ( OpenPosition ) complies with the requirements specified for the Isolationfunction in part 2 of BS-7671 .

Note : it also States a“ a “ Isolator “ is otherwise known as an “ Disconnector “

 

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Sourceof Supply .

Oftena circuit is Thought of as being the ( Load )& the conductors supplying the ( Load )
InReality they are only ( Part of the Circuit ) inorder for Current to flow two conditions have to be met .

i)There has to be a ( Potential Difference ) applied across the circuit ( Voltage )
ii)There has to be a ( Complete Circuit ) “Circle “ for current to flow around .

A Source of Supply can be ( A.C. or D.C. )

 

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Apprentices.

Determiningthe Protective Device characteristics forCircuits . ??

ElectricalInstallation Design .
Allyou need to know is to use the given details to select the Appropriate Protective Device for a given circuit .

Themain formula we can start with .

Iz > = In > = Ib .

Ib (- design current of circuit ( A ) The loadto be connected to the circuit .
In (- Nominal current of the Protective Device ( A )
Iz (- Effective current carrying capacity ( A )

Thismeans that in every circuit at all times the current carrying capacity of thecables must be ( Higher ) than the highestpossible load current .
Also. the Protective Device rating must be ( Higher) than the load current but lower than the maximum current carrying capacity ofthe cable installed .

 

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As-&-s are touchy about RCDs .

AResidual Current Device ( RCD ) will . ??
i)Operate if a Short Occurs between Line & Neutral
ii)Operate if a Small Overload occurs .
iii)Operate if Line& Neutral are out of Balance . ◄◄ “ Resi/ dual “ . Two Words - Line & Neutral

 

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2392-10(- Q )- . An Overload Current is . ?? Regulation p/27 – A )- . An overcurrentoccurring in a circuit which is Electrically Sound . :6:

 

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Thetype of Fault which occurs when a Line conductorcomes in contact with a Neutral conductor is called? ( ShortCircuit Fault ) :willy_nilly:

 

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Regulation Red book 2008 : Chapter 53 :speechless:

Protection. Isolation . Switching . Control & Monitoring .

Regulation:- The “ Term “ Isolation & Switching – as used in BS-7671 ( Refers to four distinct functions )

i) Isolation
ii)Switching OFF for mechanical Maintenance .
iii)Emergency Switching &
iv) Functional Switching

Referto Table 53.2 – p/117

 

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2392-10:- “ Consumer Controlgear “ 530.3.4. :speechless:

ForInstallation with a 230V single-phase supplyrated up to 100A that are under the control of ( Ordinary Persons) should either .

• Comply with BS-EN 60439-3 & Regulation 432.1. of BS-7671.
• Be a Consumer Unit – incorporating components complyingwith BS-EN 60439-3

 

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Regulation Chapter 532 . :- Devices for Protectionagainst the Risk of Fire . :whatchutalkingabout

532.1.Where in accordance with the requirement of Regulation 422.3.9. it is necessaryto limit the Consequence of ( Fault Currents )in wiring system from the point of view of ( Fire Risk ) THE Circuitshall be either .

i)Protected by an RCD complying with Regulation 531.2. for ( Fault Protection ) &
- The RCD shall be installed at the ( Origin of the Circuit ) to be Protected . &
- TheRCD shall Switch all Live Conductors . &
-The rated Residual Operating Current of the RCDshall Not Exceed ( 300mA) ETC .

 

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Chapter537 . Isolation & Switching .

Isolation– ( 537.2.
Switchingoff for Mechanical Maintenance - ( 537.3.
EmergencySwitching - ( 537.4 .
FunctionalSwitching - ( 537.5.

Fire-fighter’s Switches – ( 537.6 . :speechless:

A Fire-fighter’sswitch shall be provided in the Low Voltage circuit supplying :

i)( Exterior ◄ ) electrical installationsoperating at a Voltage Exceeding Low Voltage . &

ii)( Interior ◄ ) Discharge lighting installations operating ata Voltage ( ExceedingLow Voltage )

(Temporary Installation ) Fire-fighter’s Switches – ( 537.6.1.

Forthe purpose of this regulation . An installation in a CoveredMarket . Arcadeor Shopping Mall is considered to be an (Exterior Installation )
• A Temporary Installation in a Permanent Building used for Exhibitions isconsidered ( NOT to be an Exterior Installation )

 

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“ Isolation“ :icon14:

Itemsto be Considered in Relation to “ Isolation “ devices.

• Number of poles to be “ Isolated“
• “ Isolation “ of groups &inconvenience .
• Devices designed and / orinstalled to prevent Unintentional or Inadvertent closure .
• “ Isolation “ devices to beClearly Indentified and Indicate the Installation or Circuit it Isolates .

 

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Isolationrequirements for ( TN-S ) Systems .

Single-phase. L ≈ N - Circuit Protective Conductor .

Three-phase. L1 . L2 . L3. ≈ N . - Circuit ProtectiveConductor .

 

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Emergency Switching :icon14:

Whatare the requirements for Emergency Switching in relation . to

• Full Load Current .
• Hand – held devices .
• Identification of Emergency Switching devices .
• Positioning & Accessibility .
• Positioning & Identification .
• Further Danger .

 

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Firefighters Switch :

A Fire-fighter’s Switch is a Device intended for Use by Fire Service . ( Although ) NotExclusively SO :speechless:

It’spurpose is to ( De-energise ) designated parts of an Installation . That operateat a voltage in ( Excess of Low Voltage ) Neon Lighting .

 

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2392-10: :speechless:

542: Earthing Arrangements .

542.1.General Requirements .
542.1.1.The Main Earthing Terminal . Etc
542.1.2. TN-S .
542.1.3. TN-C-S .
542.1.4. TT or IT .

Chapter54 . p/124
EarthingArrangements & Protective Conductors .

542- Earthing Arrangements . p/126
543- Protective Conductors . p/128
544- Protective Bonding Conductors . p/134 .

ProtectiveConductors .
Areconductors provided for the purposes of Safety . for some measures of Protection Electric Shock . Reg - p/27

Look– fig 2.1 / p32 . Earthing & Protective conductor .

 

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2392-10:

-&-s . Q ) How many Types of EarthingSystem are recognised by BS-7671:2008 . :icon14:

A) 312.3.1. p/38 :- Types of System are . [ TN-C : TN-S : TN-C-S : TT : IT :

 

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2392-10:

TheEarth Fault Loop Impedance ( Zs ) for a Consumer’sCircuit is determined by ? :icon14:

(R1 + R2 ) + Ze

Part 2 Definitions - P/36 :

 

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TheProspective Short Circuit Current at the Origin of the Consumer’s Installationmust be taken into account when ??
Selectingthe type of Overcurrent Protective Device to be installed .

Wherepracticable Main Protective Bonding Conductor . to the Gas services in abuilding should be made within .
[600mm of the Meter on the Consumer Side ] :speechless:

O.S.G.P/27 (- Main Protective Bonding Conductors are required to connect the followingMetallic Parts to the ( Main Earthing Terminal) 411.3.1.2.
Extraneous-conductive-part : A Conductive part such as a Metal Pipe . ( LIBLE )to introduce Earth Potential into the Building.

MainProtective Bonding Conductor is the Electrical Interconnection between the MainEarthing Terminal & the incoming Metallic Services : Water / Gas .

TN-C-S. Earthing arrangements .

Regulations544.1.1. p/134 . & Table 54.8 / p134

IETwiring regulations – 17[SUP]th[/SUP] Edition . The required size of the Main Bonding Conductor is ( 10.0mm[SUP]2 [/SUP] ) for supplieswith a Neutral Conductor of ( 35.0mm[SUP]2 [/SUP] ) or Less

Becauseof this You will be required to use ( 10.0mm[SUP]2 [/SUP] ) Single Core Earth Cable toconnect both the Incoming ( Water pipe ) & the Incoming ( Gas pipe ) to theMain Earthing Terminal inside the Consumer Unit . ( CU )

 

[jeremy]

I've skimmed through the last few pages, mostly initially with a "WTF" expression, which then becomes an "AAAAH, I get it". I thank you.

 

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2392-10:

Q)- A single-phase circuit using 2.5mm[SUP]2 [/SUP] single-core PVC cables in conduit supplies adesign current of 20A .
If the cables are 15m long & have a rated voltage drop of ( 18mV/A/m ) the actual VoltageDrop will be . ????

A)- ( 18mV/A/m ) x 20A x 15m ) ÷ 1000 = 5.4V

2392-10: -&-s

Duringthe Testing Line of an Electrical Installation .Which Test would be carried out first . ????

612.2.1– Continuity of Protective Conductors . ◄
612.3.– Insulation Résistance . ( IR )
612.6. – Polarity .
612.9.– Earth Fault Loop Impedance .

 

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Megger ( 1552 / 1553 ) :speechless:

SetUp :

RCD Touch Voltage selection ( To select either 25V or 50V )

1 )With the instrument turned OFF . hold down the Yellow test button & turn the left hand rotary switch to any ON position .
2 )Keep the button held down until the instrument displays the “ SET “ Warning .
3) Now release the TEST button .
4) Pressthe TEST button again to view the currentsetting for the Touch voltage .
Thedisplay shows the touch voltage limit . 50V

Note: The MFT can also display the measuredTouch Voltage on a bar-graph display .

Ifthe touch voltage display is Active . a bar-graph display will also appear .

5) Press the ORANGE( buzzer ) button to change the touchvoltage limit setting . 25V / 50V
6) Press the BLUE (RCD ) button to turn the bar-graphdisplay ON or OFF .
7) Press the TESTbutton to exit from the set-up menu .

 

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Isolation& Switching : :49:

537.2.1. Every circuit shall be Isolated from the Live Supply.

Threepoints of Isolation .
Origin– 537.1.4.
DistributionBoards – 537.2.1.1.
FinalCircuits – 537.2.1.1.

MustIsolate all ( Phases) but not necessarily the Neutral– No link in CPC
Note (- 537.2.1.7.
Isolationat the Origin .

TN-S Phases or Lines & Neutrals
TN-C-S Phases only but both Lines & Neutral where access is Obtained by UnskilledPersons – 537.1.4.
TT- Both Line & Neutral .

 

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Isolation& Switching : :49:

537.4.2.8.
Plugs& Sockets are NOT suitable for EmergencySwitching .

 

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MainElements of Circuit design for conventional Circuits . :juggle2:

•Determine Design Current . actual flow of current through the cables ( Ib )less diversity where appropriate .
•Select type & size of protectivedevice ( In )
•Apply any correction factors to reduce self heating of cables ( It )
•Select type & size of cable fromAppendix 4 ( Iz )
•Determine whether volt drop is satisfactory for Length . Loading & routingof cables .

Note (- 2392-10
Inmost practical applications where an Installation already exists you may havethe choice of Type but only Size .

ApplyingElectrical Design . Cable Sizing .

LoadCurrent ( I ) & design current ( Ib )
Effectivecontinuous current flow through a circuit
-Basic Calculation : P = V . I or I = P/V

Whencalculating Design Current with inductive loading & where there isinsufficient information available apply a factor ( 1.8 ) to the power consumption . App 1 – Table1A O.S.G. note 2 - I = P x1.8 / V

Alternatively. if the powerfactor is known then apply ( P = V x I x Cos Ø or P = √3 x V[SUP]L [/SUP]x I[SUP] L [/SUP] x Cos Ø )

ApplyingElectrical Design . Cable Sizing .

DesignCurrent ( Ib )
Maximum Demand 311.1. ( MD )

Diversitymay be taken into account when determining MaximumDemand
Diversity– O.S.G. Appendix 1 . Table 1A . 1B .

Point to Note : Not all circuits run at their full powerrating .
CookerCircuit - Minus first ( 10A ) then 30% of the rest add( 10A ) to the Total + 5A for Socket / Outlet .

LightingCircuits :
Domesticlighting ( 66% ) is assumed to be on Continuously .

PowerCircuits :
1[SUP]st[/SUP] Circuit = Full Rating . 2[SUP]nd[/SUP] Circuit 40% & all Other Circuits . ◄◄

Diversity applies to groups of circuits or / & cables supplying groups of circuitssuch as a Sub-mains distribution boards .

 

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560.7. Circuits for SafetyServices shall be Independent of Other Circuit . :vanish:

Does NOT include Smoke Alarms & Emergency Lightingthat are ( Battery Powered ) & supplied by a ( Charging Circuit ) i.e. Lights .

 

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AppropriateBritish Standard or do a “ Risk Assessment“ :35:

• SafetyServices to be Installed to allow adequate duration equipment to be suitable tolast for the duration of Escape .
•560.5.3. – Continual ( IT ) insulation monitoring devices that give an Audibleor Visual indication of the first fault in the System .

Selection& Erection (- Safety Services . :rolleyes4:

Classification of a SafetySystem .

i)Non-automatic supply .
ii)Automatic – Self Starting .

AutomaticSupply is Classified by the following time it takes to get ( Fully Operational )

- No breaks – UPS .
- Very short breaks - < 0.15s
- Short breaks - > 0.15 < 0.5s
- Lighting breaks - > 0.5s < 5s .
- Medium breaks - > 5s < 15s
- Long breaks - > 15s .

 

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Ido fell the Humble MCB is in theBackground now . The RCD has taking Front Row . :aureola:

TimeDiscrimination :

Isachieved by delaying the Opening of the ( RCD or MCB ) upstream ( RCD or MCB ) untilthe downstream ( RCD or MCB ) has Opened & cleared the Fault .
Thetotal clearing time of the downstream ( RCD or MCB ) MUSTbe LESS than the time setting of the upstream ( RCD or MCB ) & the upstreammust be able to withstand the Fault Current for the time setting period .

Thereforethe upstream ( RCD or MCB ) must be acategory which has been designed & tested for this purpose .

MCBs- To determine timediscrimination it is only necessary to compare the Time / Currentcharacteristic curves of the Two Devices to ensurethat NOoverlap Occurs .

RCBOs – have taking a primaryrole in Industry now - RCD/MCB . ( B & C . curves ) C forLighting . B forPower .

 

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2392-10: Your first role is a Designing . second is Electrician . :aureola:

Forthe Protection of Lighting Circuits the “ Designer “ must select the CircuitBreaker with the Lowest Instantaneous trip current compatible with the inrushcurrents likely to develop in the circuit

 

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Whatis an Insulation RésistanceTest ( IR ) :aureola:

AnInsulation Résistance Test measures the total Résistance of a products’ ( Cable) Insulation System(s)
Itis also useful test to perform when doing preventative maintenance on ( Cable ) overtime .

Whatis an Insulation RésistanceTest ( IR )
Measuring& Recording long term Stability of Insulating Materials over time .

InsulationRésistance Testing . as a Tester . – The Test results can provide usefulinformation about a ( Cable Integrity ) & can yield clues when itsInsulation should be Replaced .

 

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InsulationRésistance (- 2392-10 . from -&-s point of View . :aureola:
InsulationRésistance measurement is preformed inorder to ( Assure Safety ) against ElectricShock through Insulation .

 

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ContinuityFunctions. :aureola:

Apprentices(- ParallelRésistance Paths - Interferingcurrent in measured circuit will influence the TestResults.

From-&-s point of View (- “ Nulling“ / Test Leads Résistance beforeperforming Continuity Measurement

When measuring Insulation Résistance betweeninstallation conductors all Loads must bedisconnected . ( & all SwitchesClosed ) Mains Voltage Switched OFF

“Functionality “

Regulation 612 – BS-EN 61557.

ElectricalSafety in Low-voltage distribution systems up to 1000V. A.C. & 1500V . D.C. .
Regulationsp/31 ( Low . Exceeding extra-low voltagebut not Exceeding 1000V . A.C. & 1500V . D.C. . between conductors.
Equipmentfor Testing . Measuring or Monitoring of Protective Measures .

Thecircuit under test must be Switched OFF .de-energised & Isolated before test connections are made when carrying outInsulation & Continuity Tests .

612.2. & 612.2.1.
Continuityof Protective Conductor(s) & Main Protective Bonding Conductor of New orModified Installation(s) must be verified before carrying out an Earth FaultLoop Impedance . or RCD test .

 

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Loop Impedance .:aureola:

Isa Live Test. which is carried out on a circuit to check the Résistance of the Line conductor to Earth.

Thisshows if the current created under Fault Conditions will trip the MCB .

Apprentices: Refered to as Earth Fault Loop Impedance .
-&-s . Extremely Important Test to verify the System is Safe.

TheEarth Loop Impedance test measures therésistance of the path that a ( Fault Current ) would take between Line & Protective Earth
Thismust be low enough to allow sufficient current to flow to trip a MCB

 

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2392-10. :aureola:

InterpretingResults & taking Remedial Action .
“Remember “ that it is NOT sufficient just to carry out TESTS & Record the Results .

Knowledge of Regulations . & of how to Interpret results . is alsorequired to ( Ensure the Installations ) Safetycharacteristics are within the prescribed limits .
Example(- An excessive Earth Loop Impedance value should . (Prompt an Investigation ) into its CAUSE

Asa “ Inspector “ Remedial Action should then be carried Out .& the Installation Retested .

Inspectionis the Vital Initial Operation . Testingsupports the Inspection :dupe:

 

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Workingmy way around the 17[SUP]th[/SUP] Edition :aureola:

Making you aware of Residual Current Devices .

RCDs as General Protection . ( “ Meanings “ )

►►► Protection from ( Faults ) Earth Faults currents . Shock protection ◄◄◄ :50:

531.2.1.– A residual current device shall be capable of disconnecting all the Line conductors of thecircuit at substantially the same time .

531.2.2.– The Magnetic circuit of the transformer of a residual current device shallenclose all the Live conductors of the protectedcircuit . The associated conductor shall be outside the Magnetic circuit .

531.2.3.– The residual operating current of theprotective device shall COMPLY with therequirements of Section 411 as appropriate to the type of System Earthing.

531.2.4.- A residual current device shall be so SELECTED & the ELECTRCALCIRCUITS so SUBDIVIDED that any protective conductor current whichmay be expected to OCCUR during normal operationof the Connected Load(s) Will be Unlikely to Cause unnecessary tripping of the Device .

531.2.5.– The USE of a residual current device associatedwith a circuit normally expected to have a protective conductor shall NOT be considered SUFFICIENT for Fault protection if there is NO such conductor . EVENif the rated residual operating current ( I∆n ) of the device does not EXCEED 30mA .

 

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Workingmy way around the 17[SUP]th[/SUP] Edition – Selection & Erection / Part 5

Making you aware of Effects of External Influences - ( HEAT ) :66:

Protectionof Wiring Systems by :-
-Shielding .
- Distance.
-Type of Wiring .
-Changing or Reinforcing type of Insulation .

522.2.2.– Extra insulation – ( Lighting )
522.3.- ( IP )rating for Ingress of Water .
522.4.- ( IP )rating for Ingress of Dust & Particles .
522.5.– ( Corrosion) from liquids . Electrolytic Action from dissimilar metals .

Hi. K

 

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Workingmy way around the 17[SUP]th[/SUP] Edition – Selection & Erection / Part 5

Making you aware of “ Connections “ :aureola:

526.1.Connections
- Durableelectrical continuity .
- Adequatestrength .
- Protection.

2392-10. Domestic Installation(s) Yeah :50:

 

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Workingmy way around the 17[SUP]th[/SUP] Edition – Selection & Erection / Part 5

Making you aware of “ Methods& Selection of Connection(s). :yawn:

“ ElectricalConnections “ :aureola:

- Conductor& Insulator materials .
-Number & Shape of wires forming the Conductor .
-C.S.A. of conductor .
-Number of conductors Connected Together .
-Temperature of Joint for normal Operation .
-Prevent mechanical movement under Vibration .

 

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Workingmy way around the 17[SUP]th[/SUP] Edition – Selection & Erection / Part 5

Making you aware of “ Accessibility“ :aureola:

Everyconnection shall be Accessible for Inspection
- Exceptions include . ◄◄ :50:

- Designedto be Buried .
- Compound resin Joint .
- Connectionto Floor / Ceilingheating Elements .
-Soldered . Welded . Brazed . Compressed Joints . or appropriate compressiontool .

 

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Workingmy way around the 17[SUP]th[/SUP] Edition – Selection & Erection / Part 5

Making you aware of “ Installation CircuitArrangements “ Part – 3 & 5 :dupe:

Thenumber of circuits & outlets per distribution board will be .

520.3. FundamentalPrinciples . :freak:

i)Cables & Conductors .
ii)Connections . Terminations & Joints.
iii)Supports & Suspensions .
iv)Enclosures & Protection against External Influences .

OvercurrentProtection – Chapter 43 .
Isolation& Switching – Section 527 .
Currentcarrying capacity of the conductors – Section 523 .
ExternalInfluences – Chapter 52 . 522 . App 5

CableSelection Overview .

Therequirements are :-
Thecable supplying the Load should be able to carrythe current to the Load safety . after takinginto account Diversity . without the cable Overheating– 523 . App 4

Protective Devices should beable to provide protection for the cable from Excess Current – 432. 433 .

TheLength of the cable is Limited to Ensureadequate voltage supplies the Load . 525.

MaximumLoop Impedance of a circuit is Low enough to ensure disconnection within timesspecified by Table 41.1.

( 0.4 - TN ) & (0.2 sec - TT ) for all circuits 32A ( FinalCircuits Not Exceeding 32A ) P/46
(5 sec disconnection time ) for Sub –main distribution circuits . Etc .

 

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2392-10: Protection against Shock .

Two Important Measurements mustbe taken to prevent this hazard . :50:

i) Impedance of acircuit conductors is kept to a minimum . The Earth Fault LoopImpedance under Fault Conditions .
ii) Overcurrent device protecting the circuit isselected to rapidly disconnect an Earth Fault .

 

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Room Thermostat should belocated in the part of the house where people spend the most time . it shouldbe ( 1.5m. ) above floor level .
( 0.5m away from an outside wall ) :aureola:

Relevanttests of Regulation – 612.2. to 612.13 .Example Continuity of Protective conductors & Earth Fault Loop Impedance .Applicable to parts of the system(s) such as room & cylinder Thermostats .motorized valves & programmers .

( YES ) Automatic Disconnection of Supply ( ADS ) is acommonly – used protective measures against Electric Shock in such systems .The Continuity of the protective conductorsto each point should be confirmed . This value of ( R2 ) or ( R1 + R2 ) may be used to estimate the Maximum EarthFault Loop Impedance of each control circuit for Verification Purposes . Insulation Résistancetests should also be carried out . precautions having been taken to avoiddamage . to any Electronic Components . The test results should be recorded on a Schedule oftest results .

Regulation. 411.3.1.1. – 411.3.2. – 612.9.

 

[amberleaf]

DoesBoiler pipework need to have Main Protective Bonding Conductor for ElectricalSafety Reasons . :dupe:

Thereis “ NO SPECIFIC “ requirements for Boiler pipework to be SupplementaryProtective Bonding Conductors .
However:- Such bonding may called for in the Boiler Manufactures . in which case BS-7671:2008 .requires those Instructions to be followed ( Regulation 510.2. refers )
Anystated requirements for Additional Bondingthat is considered to be Unnecessary should be queried with the Manufactures Concerned. & Amended Installation instruction requested .