Re-take - Useful Information for 2394 :

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Basics . 2394:

411.3.1.2. - Equipotential-bonding : (Making me Equal ) - “ Protective “

In each installation . main-protective-equipotential-bonding-conductor should be connected to themain-earthing-terminal for all .Extraneous-conductive-parts to create an( Equipotential-Zone ) being Metal - can make me a Conductive-part. under a fault-condition ( If ) it’s aProtective-Measure
- Water-installation-pipes . copper
- Gas-installation-pipes . copper

542.4. - ( MET ) main-earthing-terminals or ( bars )

542.4.1. - in every installation a ( MET ) shall be provided to connect the following to the (Earthing-conductor )
- Circuit-protective-conductor
( CPC - T&E) 2394: ( PE ) protective-earth . making me an . protective-conductor
- Protective-bonding-conductor(s)
Main-protective-bonding-conductor. Supplementary-protective-bonding-conductor . when required .
- Functional-earthing-conductor- if required . RCBO .

2394: the one you need is . Regulation - 544.1.2. Main-equipotential-bonding-connection to any Gas . & Water . or other services

 

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Do not mix up Circuit-breaker-side & RCD-side - to BS-EN-61009-1

Maximum-earth-fault-loop-impedance : Table - 41.3.
The Circuit-breakerside . BS-EN-61009-1 Overcurrent .32A - 1.44Ω .

 

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Maximum-demand is one of the . general-characteristics of aninstallation . that part - 3 of BS-7671:2008:2011: requires to be Assessed .
2394: from your point . Your assessing the .Maximum-demand for an installation of an - Individual-domestic-dwelling .
Maximum-demand - Regulation- 311.1.

Basics: To assess . maximum-demand - sufficient information is needed about the connected-load .
- Howthe Installation is likely to be used . &any allowance for . diversity that maybe applied .

( † ) it isimportant to ensure that your . consumer-unit are of sufficient-rating to take the total-load-connected to them without the application of any diversity .
Table- A2 ( * & † ) ◄ pointto note .

p..111 . O.S.G. - Allowance for diversity . Only be a guide . nominal-voltage 230V - rated-current-capacity 100A . Single-phase .

Question. you Maximum-demand of the installation is to be calculated . O.S.G. A2 . is tell us your - demand-factors

Allowance for diversity to be applied to an:

- Individual-household-installation . including Individual-dwellings of ablock . 2394 : - 100A .
- Small-shops. stores . offices & business-premises .
-Small-hotels . boarding-houses . guest-houses . etc .

(5)- Water-heater (( Instantaneous-type )) turn to . p.112 . ( * & † )
( * ) in contextan Instantaneous-water-heater . is considered to be a water-heater of anyloading which . heats-water-only while the tap is turned on & thereforeuses-electricity-intermittently .

- Individual-household-installation .
(9)- standard-arrangement of final-circuits . 100% of current demand of largest-point . which in our case - ( 100% is 32A )
40% of currentdemand of every-other-circuit .

(5) - Water-heater. (( Instantaneous-type * )) including-electric-shower-heaters . sometimesknown as - power-circuits . 100% . fl.of largest appliance

2394: plain-english - when you are designing an Installation it always means that . diversity must be taken into account . %

This is a Scenario Only . “ Please-read carefully “ You do Not use this Method ◄◄

To comply with . Regulation - 553.1.7. an adequate number of suitably-positioned socket-outlets areneeded for . mobile-equipment . without allowing for diversity a circuit having - ( ?? ) sixteen 13A socket-outlets. would have a potential-load of approximately - ( 208A ) This is unrealistically-large & exceededthe rated-current-capacity of the supply-providing . ( Your 100A )

To bring it back into line : 2394: So the load on the . socket-outlets-circuit(s) of a (Your Dwelling / Installation ) does NOT- depend on the numberof socket-outlets ( BUT ) on the particular-items of current-using-equipment . connected to them . twenty - 13A socket-outlets . simultaneously in use. ( diversity not all use at the sametime ) Conventional- 13A final-circuit(s)

 

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Usefuljunk . BS-EN-61009-1 .

RCBOs- this devices are functionally-dependent on the . Line-voltage for thepurposes of detection & evaluation of leakage-current . & of interruption of the supply .

The product-standard for these . voltage-dependent-device therefore requires them to trip .automatically if the supply to the [ Electronic-circuit-fails ] otherwise this would prevent their operation in the . event of an Earth-fault . This

is particularly-important in the case of a . loss of Neutral. which would otherwise leave a potential of . 230V at the Load .

facts : This automatic “ Fail-safe “ trip feature is . afforded by the connection of the “ Devices “ Thin-white or cream-lead . to the[ Earthing-arrangement of the Installation ] the lead is often-referred to as . “ Functional-earth-lead “

but ) its sole-purpose is to . provide a [ Second-reference-point ] for thesupply to the - Electronic-amplifier .

as soon as the supply . Neutral is lost . the RCD is forced to Trip . it isfor this reason . that the lead should . Not be Cut-off or .Left-unconnected .

 

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2394: Trust-me . I’ve seen some daft thing in mydays .

[ Caution ] RCBOs

Inorder to prevent-damage to the [ Electronic-components ] & to avoid erroneous-test-results . Manufactures of [ Electronic-components-RCDs ] recommend that such devices . are disconnected whilst - ( IR ) Insulation-résistance-tests . are carried OUT . ◄◄

 

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Finally Put to REST . At . [ 2/ IΔn]

However. !! . this explanation may be of help.
Familiar-currents of . - 0.5 x IΔn . - 1 x IΔn . - 5 x IΔn . as applicable . should be all that are needed when testingRCDs in the vast-majority of installations. as is the case under the . 16[SUP]th[/SUP] Edition .

[ 2/ IΔn ] test would be needed . only in .exceptional-circumstances . but evenwhere this is the case . it does not . necessarily meanthat an RCD - test-instrument having . a [ 2/ IΔn ] test-setting is required .

Therumour seems to have originated from . Note-2 . of table - 41.1 of the 17[SUP]th[/SUP]Edition . which gives . maximum-permitted-disconnection-times. for final-circuits rated at . up to [32A ] The note states that .
“ Where compliance with this . Regulation is provided by an RCD . the disconnection-time in accordance with Table - 41.1 . relate to . prospective-residual-fault-currents . significantly-higher than the rated-operating-current . of the RCD - Typically - [ 2/ IΔn ] However - Note - 2 DOES not MEAN that a [ 2/ IΔn ] testis required .

Seeif you’d remembered - Part- 6 . of BS-EN-61557

2394 : The basic-requirement of the 17[SUP]th[/SUP] Edition - 2011: [ for Testing RCDs ] with atest-instrument . which must comply with . - BS-EN-61557-6 is thatit must be . Verified that therelevant-requirements of Chapter-41 are met - Regulations - 612.8.1. & 612.10 refer .

Theserequirements ( Depend-on ) whichType-of-electric-shock-protection . the RCD is being used to provide ??? .

Provide “ What “ We have . two-methods .

i). RCD - is being used to provide [ Fault-protection ]
ii). RCD - is being used to provide [ Addition-protection ]

i) . for an RCD - being used for [ Fault-protection ] it ( Must - be - verified ) bytest that the . device would operate within the .relevant-maximum-disconnection-time permitted by the 17[SUP]th[/SUP]Edition - 2011: if an . Earth-fault-occurred. in the circuit-protected by the device .

2394: the maximum-disconnection-time permittedby - 17[SUP]th[/SUP] Edition - for A.C. circuits of nominal-voltage ( Uo -230V to earth ) are . 0.2s . 0.4s . 1s . & 5s .
inour-case here . 2394 : [ 0.4s being the most common in TN- systems . and 0.2s in TT- systems ]

Table- 3A - Time / current performance -criteria for RCDs to BS-EN-61008-1 & BS-EN-61009-1 . p.295 .
givesthe . Maximum-tripping-times for most-commonly-used-types of RCD . atresidual-current of . [ 1 x IΔn. and 5 x IΔn ] asspecified in the relevant British-Standards . 2011:

Table- 3A - it can readily be appreciated from the Table . thatwhen [ Verifying] the operation of the RCDs . listed inthis table within disconnection-times of [ 0.2s- 0.4s . 1s or 5s ] either a - 1 -IΔn test or a 5 x IΔn ] test is always suitable .

1/IΔn test is suitable for . verifying theoperation of . [ Keep in mind here . am starting with . BS- ] ONLY .

BS-4293 - or BS-7288 .Non-delay RCD . within a disconnection-time of . [ 0.2s ]
Any- Non-delay RCD .referred to in the Table - 3A . within a disconnection-time of [ 0.4s ] or 1s or 5s .

5 / IΔn . testis suitable for verifying the operation of - Any-delay-type RCD .referred to table - 3A . within a disconnection-time of 1s or 5s .

BS-EN-61008-1: or BS-EN-61009-1: non-delay RCD . within adisconnection-time of [ 0.2s ]

Not for - 2394 :
Experienced-electricians. [ 2/ IΔn ] test would be . necessary [ Only ] in . exceptional-circumstances of . [ 1/IΔn ] may legitimately not be enough to trip an RCD .within the maximum-disconnection-time permitted by BS-7671: such as where a BS-EN- 61008-1 RCD isused in a circuit where adisconnection-time not exceeding [ 0.2s is required ] but the test -instrument will perform a [ 5 / IΔn ] test for the particular rating of RCD-concerned . some RCD test-instruments will only perform a [ 5 / IΔn ] test for RCDs of rated-residual-operating-current [ IΔn ] 30mA or less .

Wherethis is the case . sufficient-test-current to trip the RCD within the required-time may be obtained by setting the test-instrument to suit an RCD of ahigher-rated-residual-operating-current . than the RCD being-tested .

Example- if a 100mA - BS-EN-61008-1 .non-delay RCD was being tested to . verify operation within [ 0.2s ] thetest-instrument could be set to test - 300mA RCD at a current of . 1 / IΔn . this would be [ Equivalent ] to testing the 100mA - RCD . at three-times its rated-residual-operating-current [ 3 / IΔn ] as can be deduced from the Table - 3A . a test-current of [ 3 / IΔn ] would be suitable to [ Verify - operation ] of the device within [ 0.2s ] as this current-exceeds [ 2 / IΔn] the current that BS-EN-61008-1 requires to cause operation within a maximum of [ 0.15s ]

ii ) . 2394 : back to basic. An RCD used for . [ Addition-protection ] musthave a rated-residual-operating-current [ IΔn ] not exceeding - 30mA & an operating-time not exceeding [ 40mS ] at a residual-current of [ 5 x IΔn] Regulation - 415.1.1. refer .

Test-procedure was used in the 16[SUP]th[/SUP] Edition . now- 17[SUP]th[/SUP]Edition . for RCDs used for this purpose is . therefore still applicable - [ 0.5non-trip . Test followed by 1x . x 5 .

2394: just a reminder . 0.5 - ½ . x IΔn . Test should also be carried out . to check for .unwanted-tripping .

 

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2394:Initial-verification . ( T ) -&-s
134.2.1. During erection & on completion ofan installation . or an addition or alteration to an installation . & before it is put into service . appropriate . inspection & testing shall be carried out by .competent-persons to verify that the requirements of this . Standard have been met .

Appropriate-certification. shall be issued in accordance with . Section - 631 & 632 - Initial-verification.

632.4. ( T ) -&-s
Defects or Omissions revealed during . inspection &testing of the installation work covered by the . Certificate shall be made good before the Certificate is issued .

GN-3. just an Example .

Inspection& Testing . explains that . among other things . the purpose of periodic-inspection & testing is to provide .so far as is reasonably-practicable . for the identification of installation - defects & non-compliance withthe requirements of the Regulations -BS-7671: whichmay give rise to danger .

 

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Useful-junk.

Statutory-requirements. “ Socket-outlets “

Exceptin Scotland . There are no-statutory-requirements in the United-Kingdom regarding the “ Minimum-number “ of socket-outlets to be provided in a dwelling .
Exceptin Scotland - 1990 - Part Q .

O.S.G.- P.178 . Table - H7 . Gives - recommendations on the . [ Minimum-provision ] Twin-socket-outlets to be provided in homes .

 

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O.S.G.- A2 . Small-business-premise ..

Worked-example . Connected-loads . Diversity-factors . Calculation of Maximum-demand

Description- High-frequency discharge-lighting .
Number-ofpoints-served - 12 .
Connected-load. per-point . - 64 VA .
Total-connected-load of all points . 768 VA ÷ 230V = 3.34A .

Allowance for diversity - from Table - A2 - Type of premises !! . Small-business-premise . Etc . Lighting - 90% of the connected-lighting-load .
Resulting-contribution to maximum-installation-demand . - 3.00A

 

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Worked-example . Connected-loads . Diversity-factors . Calculation of Maximum-demand

Description- Instantaneous-water-heater .
Number-ofpoints-served - 1 .
Connected-load. per-point . - 2.5 kW .
Total-connected-load of all points . 2500W ÷ 230V = 10.87A .

Allowance for diversity - from Table - A2 - Type of premises !! . Small-business-premise . Etc . 100% - Fl . of largest plus 100% -Fl . of 2[SUP]nd[/SUP] largest - appliance plus 25% Fl . of remaining -appliances .
Resulting-contribution to maximum-installation-demand . - 10.87A

100%- Fl . Number-of points-served - 1 . 2.5kW . 2.500W ÷ 230V= 10.87A
100%- Fl . Number-of points-served - 2 . 2.5kW . 2.500W ÷ 230V= 10.87A

(FL ) denotes full-load .

 

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Whatis Overload-current .
Interms of the definitions given in .Part - 2 .

- Overload-current is . An overcurrent-occurring in a circuit which is . electrical-sound “
And.
Overcurrent - which is mentioned in the definition of overload-current . is . “ Acurrent exceeding the rated-value . forconductors the rated-value is the . Current-Carrying-Capacity “

Itshould be noted - that the term “ Overcurrent “ includes both . Overload-current and Fault-current.

 

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Circuit-breakers - BS-EN-60898 . some facts .

Where- BS-EN-60898 . circuit-breaker is to provide . Overload-current-protection .the requirements - Regulation - 433.1.1. condition (iii) are to be complied with . the current ( I [SUP]2 [/SUP]) causing the effective-operation of the protective-device . is not to exceed ( 1.45 - times ) the lowest current-carrying-capacities ( Iz ) of any of the conductors of the circuit .

BS-EN-60898- circuit-breakers have aconventional-tripping-time ( I[SUP] t [/SUP] ) which is equal to ( 1.45 / In ) . This means that the current ( I [SUP]2 [/SUP]) causing the effective-operation of the circuit-breaker is . ( 1.45 - times ) the nominal-current or current-setting ( In ) of the BS-EN-60898 . The term “ conventional-tripping-current “ meansthe same term “ current ensuring effective-operation ofthe protective-device “ whichis used in . Regulation - 433.1.1.

Therefore. where nominal-current or current-setting of a BS-EN-60898. circuit-breaker is selected such that - Regulation - 433.1.1. condition ( ii ) is met . then condition ( iii ) of the Regulation . will also be met . This is confirmed by Regulation - 433.1.100 .

Short-circuit-capacity:
A circuit-breakerconforming to BS-EN-60898 . which hastwo-defined . short-circuit-breaking-capacities ( Ultimate & Service )

Miniature-circuit-breaker- conforming to . BS-3871 . Part - 1. has only one . short-circuit-capacity . designated as its. “ Category of duty “ thisis marked on the device .

 

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2394: If in doubt the O.S.G. will simplify , p.151.

Fundamentally. Two-types of form are recognisedby. BS-7671 .

- Certificate are issued for . New-installation-work . Q) . whatwould I be . - ( EIC ) Electrical-installation-certificate .
-Reports are issued for . inspections of Existing-installations . Q) . whatwould I be . -( EICR ) Electrical-installation-condition-certificate.

G2- Certification : Watch your . Wording . in Exams

Two-types of certificate for . ( New-work ◄ ) . are recognised by. BS-7671 .

Q). what would I be . ( New-work ◄ ) - ( EIC) Electrical-installation-certificate.
Q). what would I be . ( New-work ◄ ) - ( MEIWC ) Minor-electrical-installation-work-certificate .

(EIC ) Electrical-installation-certificate. is “ Safety-certificate “ :aureola:

 

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2394: learning-curve . what is Testing & Inspection . all about .

( Private-landlords) I’ve waited 5-years before anything was done .
Soyou can see I think there money crabbing **** .

That’swhy I’ll fight all the way . on this . matter .
The landlord . sent round . a ( Plummer ) to check my Electrics . AM - PART-P . Qualified . I politely told him to get the hell out the House . :6:

I issuedan Certificate . with major-faults on it 3/half years ago . (Dusty-bin got it )

I’ll kill two-birds’ with one stone here .

Firstly: 27/9/12 . N***** - Inspector . because it is an Exiting-installation .he used an . Domestic-electrical-installation-condition-report .
Time on site . 3/half hours . because of . ( LIM ) limitations ◄ . this will --- up on your Exams Etc .

12- faults . 8 - CI . 4 - C2 . Unsatisfactory . oneor more issues of safety have been identified .

O.S.G. - p. 152 . will simplify .

Unsatisfactory . oneor more issues of safety have been identified .
Where an unsatisfactory . result has been recorded . C1 and / orC2 - observations will have beenincluded indentifying the reason(s) for the result . Once the report has been issued by the ( Inspector ) the ( Onus is then placedon the Client to Act ) in responseto the ( Observation - recorded)

C1 - Danger-present . Risk of injury . Immediate remedial-action required .
C2 - Potential-dangerous- Urgent . remedial-action required .

C1 - Where danger currently-exists . & an immediate-issue of safety is apparent .
C2 - Not immediately-dangerous but a . dangerous-condition could occur due to a fault .

p.153. G3.3 - Dangerous-situation . ( learning-curve )
The Inspector is advised to exercise-judgement to secure the area & inform the ( Client . **** ) immediately . followed up inwriting . Once permission has been obtained . the danger should be removed .

Exercise-Judgement whichthe Inspector . did . - Hecould shut down the problems . without . turning of 4 - circuit-breakers . ( I only have 6 - way )

Judgment- day tomorrow . ( Will make eye contact )

 

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2394: It’s all in the books . ( Addition or Alteration ) ◄► ( Existing-circuit ) Not a New-circuit . “ it’s all in the Wording “

(MEIWC ) Minor-electrical-installation-work-certificate. Regulations. GN-3 .

O.S.G.p.151. simplified .
The Minor-electrical-installation-work-certificate. is intended to be issued where more significant-installation-work. is undertaken .

- Adding lights to a . lighting-circuit .
- Adding socket-outlets to a ring-final-circuit.
- Rerouting an ( Existing-circuit)
-Replacing an ( Existing-shower ) with alarger-power-rating of unit . PS. You have to check the size of cable . is it . 6.0mm[SUP]2 [/SUP] / 10.00mm[SUP]2 [/SUP]
-Replacing circuit-breaker(s) with . RCBOs where there is a difference of . Overcurrent-type . ( replacing - characteristics type C or B )

in each case . the characteristics. of the circuit are likely to have been altered . whether it’s the . ( addition ) ofextra-load or changes to the original . earth-fault-loop-impedance.