Re-take - Useful Information for 2394 :

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Magnetic-characteristic . Circuit-breaker(s)

letter B , C , or D , represents a multiple of ( In ) When the current rises to thismultiple value , the magnetic operates instantaneously to open the trip operates instantaneously to open the contacts.

 

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Re-cap.

Firstly - ( Protective-devices in question ) The Regulations have stated the Facts .

533. p/139 . Devices for protection against Overcurrent :

533.1. General-requirements .
A device for protection against Overcurrent shall comply with one or more of thefollowing :

• BS-88 : Series
Appendix - 1 . p/277 . ( Normative)
BS-88: The term “ BS-88 : Series “ . when used in these Regulations . ( Means ) BS-88-1 , - 2 , - 3 .

• BS-646
Appendix - 1 . p/277 . ( Normative)
BS-646:1958 ( 1991 ) Specification .Cartridge-fuse-links . ( rated upto 5 amperes ) for a.c. & d.c. service .
BS-646: remains-current but the requirements for . type - B . fuse-links have been replaced by . BS-2950:1958

• BS-1362
Appendix - 1 . p/278 . ( Normative)
BS-1362: 1973 ( 1992 ) Specification for general-purpose-fuse-links for (Domestic & similar purposes ) Primarily - for use in plugs.

• BS-3036
Appendix - 1 . p/278 . ( Normative)
BS-3036: 1958 ( 1992 ) Specification . Semi-enclosed-electric-fuses. ( ratings up to 100- amperes & 240V to Earth .

• BS-EN-60898-1 . & - 2
Appendix - 1 . p/285 . ( Normative)
BS-EN-60898: 1991 . Specification . for circuit-breakers for overcurrent-protection for ( Household & similar installations ) Replaced by BS-EN-60898-1 : 2003 : but remains-current .

Appendix - 1 . p/286 . ( Normative)
BS-EN-60898-1: 2003 . Circuit-breakers for a.c. - operation .

Appendix - 1 . p/286 .
BS-EN-60898-2: 2001 : Circuit-breakers for a.c. & d.c. . operation
BS-EN-60898-2: 2001 . remains-current . ( It was withdrawn in error & has been reinstated )

• BS-EN-60947-2 . & - 3
Appendix - 1 . p/286 . ( Normative)
BS-EN-60947-2: 2006 . Circuit-breakers .

• BS-EN-60947-4-1 , - 6-1 & - 6-2
Appendix - 1 . p/286 . ( Normative)
BS-EN-60947-4-1: 2001 ; 2001 . Contactors & motor-starters - Electromechanical-contactor & motor-starters .

• BS-EN-61009-1 .
Appendix - 1 . p/287 . ( Normative)
Electrical-accessories.
Residual-current-operated, circuit-breakers with , integral-overcurrent-protection for (Household & similar uses ) RCBOs . General-rules . ( Making me Part-1 )

 

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Still some confusion with (IP - Codes ) in the Regulations’

The Regulation’s , have stated the facts . :svengo:
Note :
( Barrier or Enclosures ) are intended to prevent-contact with ( Live-parts ) Hand’s & finger’s

Barriers or enclosures . 416.2.

IPXXB :- denotes protection against - finger-contact-only
IPXXD :- denotes protection against - penetration by 1mm diameter-wires-only

IPXXB - IP2X
IPXXD - IP4X

X - Indicates no specified-protection .

First-numeral , Mechanical-protection .
Second-numeral . Liquid-protection .

The most commonly-quoted ( IP -Codes ) in the , 17[SUP]th[/SUP] Edition - 2008:2011:
IPXXB - IP2X
IPXXD - IP4X

2 ) Protection against ingress of large-solid-foreign-bodies .
- Protection against contact with live or moving-parts ( Inside the enclosure ) by fingers
- Protection against ingress of medium-size-solid-foreign-bodies

4 ) Protection against contact with live or moving-parts ( Inside the enclosure ) by Tools . wires or such objects of thickness greater than ( 1mm )
- Protection against ingress of small-solid-foreign-bodies

416.2.2. p/67 .
A ( horizontal-top surface ) Top of Consumer-unit . or enclosure which is readily-accessible , shall provide a degree of protection of at least IPXXD - IP4X

416.2.3.
A ( Barrier or enclosure be firmly secured in place ) & have sufficient-stability & durability to maintain the required-degree of protection . Etc

416.2.4. Where it is necessary to remove a ( Barrier or open an enclosure) or remove-parts of enclosure(s) , this shall be possibly-only

Your three-main-points , here .

- By the use of a key or Tool

► Safe-Isolation . re-cap

- After disconnection of the supply to live-parts , which the ( Barrier or enclosures afford protection )

- Restoration of the supply being-possible-only after replacement or reclosure of the ( Barrier or enclosures )

- Where an ( Intermediate-barrier providing a degree of protection ) of at least , IPXXB or IP2X prevents-contact with live-parts .

2392-10 / 2394 : By the use of a ( Key or Tool ) to remove the intermediate-barrier . ( Screwdriver )

Gentlemen:
Point to Note here . All it takes is little-pressure to hit (The Button ) THANK -YOU .
Even Amber has to go through BOOKS . GN-3 , 17[SUP]th[/SUP] Edition , O.S.G. & type up

 

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Inspection . Testing & Certification .

Two-types.

Initial-Verification. 2392-10
Is required for New-Work . & (Alterations & Additions )

Periodic-Inspection & Testing
Is required for ( Existing-installations ) & Initial-Verification. 2395

Regs. p/36 .
Verification :
All measures by means of which compliance of the electrical-installation with the relevant-requirements of BS-7671: are checked , comprising
Inspection
Testing
Certification

 

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2392-10. re-cap Appendix - 15 ( Informative) :icon_bs:
p/425- Ring & Radial-final-circuit .

Ring-final-circuit-arrangements. Regulation - 433.1.103 . p/81.

The load-current in any part of thecircuit should be unlikely to exceed for long-periods the current-carrying-capacity of the cable .

433.1.103. This can generally be achieved by :
i) Locating socket-outlets to provide reasonable-sharing of the load around the ring .

the only-mention of this is in Appendix - 15 . (ii) p/425 … comply with Regulation - 433.1.103
ii) Not supplying ( Immersion-heaters) comprehensive ( Space-heating ) or loads of a similar-profile from the ring-circuit .

iv) Taking account of the ( Floor-area ) being served . a limit of 100m[SUP]2[/SUP] has been-adopted . Etc

O.S.G.. p/177 H5 . re-cap
Water & Space-heating

Water-heaters fitted to storage-vessels to excess of ( 15- litres-capacity ) or permanently-connected-heating-appliances forming part of a comprehensive , Space-heating-installation ,should be supplied by their own-separate-circuit.

( Immersion-heaters ) 16A - circuit-breaker . & a 20A DP - switch .


Comment in ( GN-1 ) is ( Immersion heaters ) should Not be connected using a plug and socket-outlet , but a switched-cord-outlet-connection-unit complying with BS-1363-4 .

BS-1363-4. p/278 .
BS-1363-4: 1995 . Specification . for 13A fused-connection-units , switched & unswitched .

559.6.1.1. p/177. Connection to the fixed-wiring .
(vii) A connection -unit to BS-1363-4 . … 13A fused-connection-unit . We have the 16[SUP]th[/SUP] Edition . still out there .

Refer . Appendix - 15 fig 15B . p/426 .
Table 53.4.


Origin of an Installation : p/31
The position at which electrical-energy is delivered to an electrical-installation. 2392-10

 

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Corrigendum - 2011

Smart meters and dumb fires

Smartmeter rollout
Oneadvantage of smart meters is that the suppliers will no longer have to employan army of people to knock on doors to physically inspect meters and ensurethat readings are accurate and no unauthorised tampering has taken place.
However,the supplier will need to mobilise legions of smart-meter installers. Most havereached the logical conclusion that they ought to retrain some of theirexisting meter operators, inspectors and readers. They are also advertising job vacancies specifying no experiencenecessary since you do not have to be a qualified electrician to replace anexisting meter with a smart one.
Extracts :
Othershave voiced concerns about the safety of the work being carried out. TheElectrical Safety Council (ESC), whose recommendations are supported by a rangeof industry bodies, wants an isolating switch built into smart meters. Thiswould allow contractors a simple and safe means of isolating the electricitysupply in UKhomes when necessary, such as for the replacement of a consumer unit.
Theonly way currently to isolate the supply is to remove the electricitydistributor's cut-out fuse but electricians are not authorised to do this. TheESC claims that efforts to provide such permission have been blocked by theelectricity supply industry.
Extracts :
Despitebeing unauthorised, many electrical contractors remove cut-out fuses whennecessary, as the legitimate alternatives cost time and money for bothcontractors' businesses and their clients, says the ESC.
Asan added safety measure, smart meters are being designed to give a ( last gasp' alarm signalif the supply to the meter is cut ) Thiswill immediately alert the authorities toany unauthorised removal of a cut-out fuse. ◄◄

http://eandt.------.org/magazi...y-of-our-own-homes.cfm


Question, how many training hours will beavailable to bring a ' Non-experienced ' person up to a ( Competent - Standard ?)

 

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2392-10 .

Earth-fault-loop-impedance: ( Circuit-loop-impedance )

All necessary safety-precautions must be taken . With any Testing .

This test has to be carried out on an Energized-installation.

The purpose of this test is to ensure that , in the event of a Line-to-Earth-fault.

Circuit-breaker: Enough-current will flow around the Earth-fault-loop-path . to operate the protection within a specified-time .

• The measured-value of loop-impedance is then compared with that given in the Regulations .

GN-3. p/83 . Earth-fault-loop-impedance-tester .. BS-EN-61557-3 .

This Instrument-functions by creating . an Earth-fault .
2392-10 : is connected to the circuit via a plug . in your case Only.
Or
By “ Flying-leads “ connected-separately to Line , Neutral , Earth .

p/84 . RCD Tester(s) BS-EN-61557-6
2392-10 : is connected to the circuit via a plug . in your case Only .
Or
By “ Flying-leads “ are need for Non-socket-outlets-circuit(s) that’s why you have , Three-leads on your Test-instrument . for Use OFF

 

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NewMicrosoft Words .
Microsoft Words 2003 .does not leave a double-cap when typing. scrambles it together . on down load to the forum
Notethatthe “ O.S.G. “ does not express any preference between ring-final or radial-circuit(s) Both circuits areavailable to designers for use on their systems as they see fit .
O.S.G. Table – H2.1 . p/174 . Ring / Radialcircuit(s) A1 , A2 , A3 .
Designer to develop final-circuit(s)covering different floor areas and using different ratings of protectivedevices if he determine that the current drawn by devices connected to thecircuit and the diversity in use between the devices would allow different circuitarrangements to be used
O.S.G. is a handbookthat contains information not in BS-2008:2011: O.S.G. remindsus . it is a meant as a handy notebook reference for Electricians . working on building sites

 

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p/174 . Plugs and Socket-outlets. PS just some facts .


Regulation 553.1.100 states: “ Everysocket-outlet for household and similar use shall be of the shuttered type and , foran a.c. installation , shall preferablybe of a type complying with BS 1363. ”


Socket-outlets in excess of 13A, e.g.
Industrial types to BS EN 60309-2, are industrialtypes to BS EN 60309-2, are available in current ratings of 16 , 32 , 63 , 125A, but are not intended for household orsimilar use. Generally, these socket-outlets do not incorporate an integralshutter system.

 

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Useful – Junk : Where did the “ Word “ ring-circuit come from . ????


The start of the “ Ring-final-circuit “


Post War Building Study No 11 .


“ Electrical-installations “ waspublshed in . 1944 Section 76 gavebirth to the “ Ring-final-circuit “


We recommend thatsmall-dwellings of the types considered should be wired with three-seprate-circuits for lighitng , cooking , & socket-outlets respectively , each controlled by a separate single-pole-fuse , it is proposed that all socket-outletsshould be supplied from a “ Ring-final-circuit “ which , starting and ending at the fuse-terminal at the consumer.s supply control will pass through each room in turn .in the small dwellings under consideration it is considered permissible to connect up to 20 of the proposed standed-socket-outlets onthe “ Ring-circuit “ At theconsumer.s supply control the “ Ring-circuit “ willbe fused for 30 Amperes , a currentwhich is unlikely to be exceeded in the conditions of ( Load-diversity ) metwith in small-dwellings , At each outlet position on the “ Ring-circuit “ itwill be necessary to provide , a cartrigde-type-fuse for local-protection With regards to the socket-outlet-circuit ,the recommendation to connect a number of standard-socket-outlets on a “ Ring-circuit “ represents a departure from existing practice as laid-down in the wiring-regulation ( Eleventh-Edition )


With “ Ring-circuits “ rated at 30A and up to twenty-socket-outlets connected to the circuit , it was therefore necessary to incorporate a fuse on the ( Appliance-sideof the Electrical-system ) this led to the deveopment of “ British-Standard “ 1363:1947 . Fused-plugs & Shuttered-socket-outlets , Introduced in 1947.

 

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No- Socket Covers are in sight .


- - - Updated - - -

Just some Facts . Shutter – Mechanism :

BS-1363 :
Accessories to BS-1363are made to exacting requirements so that the plug perfectly fits thesocket-outlet . when BS-1363 was definedin the 1940s the designers wanted to make sure that the socket-outletwas verysafe , The standard requires that an interlocking shutter suystem stop randomobjects from being inserted into the socket-outlet(s) be inserted a distanceof 9.6mm into the socket before it makescontact with any live parts , the shutter system will operate and open toexpose the Line & Neutral-connections only when a plug is inserted .


It is Actioned by :
- The earth pin of the plug
- Both the Line & Neutral pinssimultaneously
- All three pins ; first the Earth pin follwed by both the Line & Neutralpins simultaneously

BS-1363: Therefore , already incorporates a mechanisum which stops intentional andunintentional . Direct contact with ,Live parts
Shutter –Mechanism : ( Under Nornal-Conditiond ) Shutter – Open . Earth pin present .
Shutter– Closed . No Earth pin inserted .


British 13 Amp sockets have built in automaticshutters to protect against children poking things in.


UK law requires all sockets sold to conform to the current BS-1363 standard , this is what ensures yourchild’s safety.
It was originally introduced in 1947 as:British Standard 1363 : 1947 FUSED PLUGSAND SHUTTERED SOCKET OUTLETS.


Regulation 553.1.100 States: “ Every socket-outlet for household and similar useshall be of the shuttered type and , for an a.c. installation, shall preferably shall preferably be of a typecomplying with BS 1363. ”


Plug pin dimensions in BS-1363-1.
BS-1363-2 socket-outlets due to the fact that protectionagainst access to the live and neutral socket contacts is always provided bythe shutters.

 

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BS-7671:2008:2011: have stated theFacts . Requirements for Testing : 2392-10 /2394 . The Sequence of (Tests ) Regulation – 612 . p/190 . Lists the sequence in which ( Tests ) should be carried out . Colum – 5 .under 612.1. Note : if any ( Test ) indicates a failure to comply .That test and any preceding-test . the results of which may have beeninfluenced by the fault indicted , shall be repeated after the fault has beenrectified . BS-7671:2008:2011: have stated theFacts . 612.2 / 13 . Initial-tests should be carried out in thefollowing-sequence where applicable , before the supply is connected or withthe supply disconnected as appropriate .

- - - Updated - - -

BS-7671:2008:2011: have stated theFacts .

Requirements for Testing : 2392-10 / 2394 .

TheSequence of ( Tests )
Regulation– 612 . p/190 . Lists the sequence in which ( Tests ) should be carried out .

Colum– 5 . under 612.1.
Note : if any ( Test )indicates a failure to comply . That test and any preceding-test . the resultsof which may have been influenced by the fault indicted , shall be repeatedafter the fault has been rectified .

BS-7671:2008:2011: have stated theFacts . 612.2 / 13 .
Initial-testsshould be carried out in the following-sequence where applicable , before thesupply is connected or with the supply disconnected as appropriate .

 

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Inadequate testing of the power circuit , by relying solely on theuse of a voltage tester, commonly known as a ‘ Volt-stick ’ :13: Test before you touch – prove and verify the supply is de-energised by using appropriatetest methods and approved testinstruments, to test for the absence of voltage on ( All conductors ) including the Neutral-conductor ‘Volt-stick’ Thesetypes of testers must ( Not be relied upon ) toprove isolation in all circumstances.
Do We . !!
When ( Voltage testers ) are used to prove de-energisation, they must betested for correct operations immediately before use, and again immediatelyafter use – particularly if the test result indicates zero voltage – to confirmthat the instrument is still working correctly. :6:

 

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Useful-junk TheTerms .Exposed-conducting-parts & Extraneous-conducting-partswere first introduced into the 15[SUP]th[/SUP]Edition of the IEE Wiring Regulations Note: also that the current through the body is detrrmined notby the . RCD – sensitivity but by the , Voltage & Circuit-resistancee. Body-resistance RCDrated at 30mA will provide degree of protection . ( Additional ) ------ specify the use of . 30mA RCDs in most instances to give enhanced safety . The 15Edition required these to tripin . 40mS or less with a leakage-current of . 250mA Whereasthe 16[SUP]th[/SUP]Edition stipulates that the device should trip within . 40mS at aleakage of 150mA

- - - Updated - - -

Useful-junk

The Terms . Exposed-conducting-parts& Extraneous-conducting-parts werefirst introduced into the 15[SUP]th[/SUP]Edition of the IEE Wiring Regulations

Note : also that thecurrent through the body is detrrmined not by the . RCD – sensitivity butby the , Voltage & Circuit-resistancee . Body-resistance

RCD rated at 30mA willprovide degree of protection . ( Additional)
The IET specify the useof . 30mA RCDs in most instances to give enhanced safety .

The 15Edition required these to tripin . 40mS or less with a leakage-current of . 250mA

Whereas the 16[SUP]th[/SUP]Edition stipulates that the device should trip within . 40mS at aleakage of 150mA

 

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As Electricians, Have you ever beenAsked ??? ( 1000 – times ) Why doRCDs sometimes trip Unnecessarily
Residual current devices (RCDs ) are usedextensively in installation to provide (Fault-protection ) & ( Additional-protection ) againstelectric-shock
Since the introduction of the 17[SUP]th[/SUP]Edition of the IET Wiring Regulations most, if not all final circuits in a newor re-wired installation in domestic premises to be provided with , ( Additional-protection by an RCD ),having a rated residual operating current ( I∆n ) of 30mA and an operating timenot exceeding 40mS , at 5 I∆n
While RCDs provide an ( Enhanced Level ) ofShock-protection, precautions should be taken to avoid , Unwanted-tripping ofthe devices on healthy circuits, Repeated unwanted tripping is likely to damageuser confidence in RCDs, and has been known to result in them being bypassed byfrustrated consumers.
Unwanted tripping of RCDs can be caused bythe current that may flow in the protective-conductor of circuit supplying certainitems of Class-1 earthed-equipment during their normal operation, Such items includeequipment-incorporating :
• Electrical noise – ( radio-frequency ) suppression filters, such aspersonal computers’, hi-fi equipment, TVs, DVDs, & the like .
• Heating-elements, such ascookers, water-heaters or radiant-heaters Etc .
• Motors, such as fridges &Freezers ( Common )
To avoid unwanted-tripping, RCDs shouldbe so selected and circuits so subdivided that any protective-conductor currentexpected to occur during normal operation of the Load(s) will be unlikely tocause tripping of the device.
Facts :That product standards permit certain equipment, such as personal computer’s tocreate up to 3mA of leakage currentin the protective-conductor
In order to minimise the risk ofunwanted tripping of RCDs, the number of items of protective-conductor-currentgenerating equipment per circuit, and the number of circuits’ served by eachRCD, need to be sufficiently small .
Tripping of an RCD may result if thetotal protective-conductor-current in the circuit(s) it serves exceeds ( 50% )of it’s rated residual operating current, that is ( 15mA for a 30mA device )