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

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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 )

 

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Whys?. We use 32A Ring Mains for Extra safety & part of the old standards for harmonisingwith the rest of Europe .

433.1.5 – follow Up .

2.5mm[SUP]2[/SUP] x ( 2 ) is 54A so with a balanced current in each Leg .the wires can handle 54A .

2392-10. You make up your on Mind on this Matter . ◄

Example- 4D5
ARing Final Circuit . has two 2.5mm[SUP]2[/SUP].cables . a 2.5mm[SUP]2[/SUP].cable is rated to carry ( 27A ) if & onlyif its clipped on the surface .
Itcarries less when its installed in walls . behind plasterboards . Etc

Each 2.5mm[SUP]2 [/SUP]will nevercarry the same amount of current different lengths on the legs gives different currentsin each leg . Using a conservative ( 2/3 ) of the total current in one leg . Thiscould mean ( 26.67A ) flowing through one ( 2.5mm[SUP]2 [/SUP]) whichis on the absolute limit of the cable even if the whole circuit was clipped onthe surface

 

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433.1.5.

i)Accessories to BS-1363 . may be supplied through a Ring Final Circuit – with orwithout Unfused spur .
ii)Protected by a ( 30 or 32A ) protective device [ complying with BS-EN 60898/ MCB . BS-EN 60947-2 / MCCB. or BS-EN 61009-1/ RCBO ] the rest I left out

ii)You need the manufactures data for these . They will have different characteristicsto BS-EN 60898.Different Circuit/ Breakers
will not come under you Verification . 2392-10 . New / Installation :26:

BS-EN 60947-1
BS-EN 60947-2 - ( Single –phase/ Three-phase ) 100A . 63A . 20A
BS-EN 60947-2 - ( Donot have Characteristics like MCBs you need toconsult the Manufactures ) – Make & Model .
BS-EN 60947-3 - Switch Disconnector / Isolator .

Look in the . O.S.G. P/57 – Bottom/ The Short-circuit capacity of devices to BS-EN60947-2 ( is as Specified by the Manufactures) BS-EN 60947-2 / Regulation(s) 433.1.5

UsefulJunk : MCBs / New

► BS-EN 60898. Time / Current Characteristics .
B(- range of trip ( 3 to 5 In ) Load type – Resistive .
Range(- Domestic . Heaters . Shower(s) . Cooker(s) . GeneralSocket Outlets . Etc

C(- range of trip ( 5 to 10 In ) Load type –Inductive . Etc
Range(- Motor(s). General lighting circuit(s) . Power Supplies .Etc

D(- range of trip ( 10 to 20 In ) Load type –High / Inductive .
Range(- Transformer(s). Motor(s) . Dischargelighting circuit(s) . Computer(s) Etc

UsefulJunk : MCBs / Old/ 3871 – Range . O.S.G. . P/57 3871 ◄◄

1 (- range of trip ( 2.7 to 4 In ) Load type– Resistive .
Range(- Domestic . Heaters . Shower(s) . Cooker(s) . GeneralSocket Outlets . Etc BS-1363

2 (- range of trip ( 4 to 7 In ) Load type– Resistive /Inductive .
Range(- Small Inductive . Switching Load(s) Lighting& Domestic circuit(s) . Etc

3 (- range of trip ( 7 to 10 In ) Load type– Inductive .
Range(- Motor(s) . General Lightingcircuit(s) . Supplies . Etc . I leaf out ( 4 )

Asa Designer .
2392-10 (- Installation(s) should be arranged so as toavoid Danger in the event of a Fault ( i ). & ( ii ) the facilitate safe operation . Inspection /Testing & Maintenance .
Yourcomply with Regulation - 314.1. (iii )

Notto confuse the “ Apprentices “ . :aureola:

BS-3871 .. ( Obsolete ) has been Replaced by ( BS-EN 60898 )
Theare still out There . 16[SUP]th[/SUP] Edition . O.S.G. P/57

ShortCircuit Capacity ( Icn ) – Amperes ( A ) MCBs / BS-EN 60898 .

TheWhy’s are coming out Now . ??
Regulation433.1.1. . Says that ( ALL ) conductor(s) mustbe protected a ( Fuse/Breaker ) to PROTECT the CABLE . should anOvercurrent flow .( Iz )

Circuitshould be wired with Copper Conductor(s) having Line & Neutral conductor(s)with a minimum ( C.S.A. ) 2.5mm[SUP]2[/SUP]. Such circuit(s) are deemed to meet the requirements of Regulation . 433.1.1.

Now(- ( IF) the CurrentCarrying Capacityof the cable is NOT less than ( 20A ) . &
Underthe intended conditions of Use . The load current in any part of the Circuit isUnlikely to exceed for long periods the current [ Current Carrying Capacity ofthe Cable ]

 

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Point to Note . Here . Amber . :welcome2:

Without any Thank You . I don’t know if am in the Right Direction .

Please hit the ( Like Button ) it does help me OUT. PS. What’s a click on the Button . ( A Lot To Me ) :aureola:

 

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Apprentices (- Regulation . Chapter 31 – p/38

Purpose. Supplies & Structure .

312.3.1. Type of Earthing Arrangement .
Thetype of Earthing System to be used for installation shall be determined , due accountbe taken of the Characteristics of the source of Energy . &
Inparticular of any facilities for Earthing .

There Asking us . ??
:aureola: i) Will the Supply & Earthing arrangements will be Satisfactory.
ii) There may be a need to ( Alter ) the arrangementof the ( Installation )

Apprentices. Initial Verification “ is “ New Installation . ( your going down the Road of 2392-10 )

 

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2392-10(- Design & Verification . ( Full Title –Switch Disconnector ) :66:
Capableof Switching both Resistive & Inductive Loads.

Regulation. Table 53.2. ( Switching Devices) Isolation “ Wylex 100A “ on ConsumerUnit .

SwitchingDevices BS-EN 60947-3 . Yes[SUP]( [/SUP][SUP]1[/SUP][SUP])[/SUP]

Yes/ Function provided .
[SUP]( [/SUP][SUP]1[/SUP][SUP])[/SUP] Function provided if the device is suitable &marked with the symbol for isolation ( see BS-EN 60617 ) identity number S00288. )

( Switching Devices ) Isolation “ MK – Main Switch 100A “ on Consumer Unit .

EN-60947-3 ◄◄

Yes/ Function provided . Wylex
[SUP]( [/SUP][SUP]1[/SUP][SUP])[/SUP] Function provided if the device is suitable &marked with the symbol for isolation ( see BS-EN 60617 ) identity number S00288. )

Youare complying with Regulations . 17[SUP]th[/SUP]Edition 2008 .

 

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Useful Junk .

Cable Reference :

CC – Bare copper sheathed .
MI - Cable .
V – PVC covered .
M – Low smoke & fume . ( LSF ) materialcovered .

L – Light duty ( 500V )
H – Heavy duty ( 750V )

Hence– a two-core 2.5mm[SUP]2 [/SUP] light duty ( MI ) cable with PVC oversheath would be ?? ( CCV –2L . 2.5 ) Next time look at your Pyro Cuter Tool ??

MineralInsulated copper sheathed ( MICS ) Cable . “ Fire Alarms“ :66:

 

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UsefulJunk .

RingFinal Circuit : OneSolution . :aureola:

i)To indentify breaks in the Ring FinalCircuit & Interconnections across the Ring .
ii)Test with a Low Reading Ohmmeter between each ( L . N . & E . Leg ) &the corresponding terminal at the nearest socket .
- A Low value indicates the short leg .
- A High vale the Long Leg .

► Reading at Mid-Point = 30m of 2.5mm[SUP]2[/SUP]+ 30m of 1.5mm[SUP]2 [/SUP]--- 2

=30 x 0.00741 + 30 x 0.0121 ÷ 2 = 0.293Ω
[ 30x 0.00741 + 30 x 0.0121 = 0.5853 )- ÷ 2= 0.293Ω ]

ThisValue is ( R1 + R2) Ring Final Circuit .

30m/ half of - 15m

 

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UsefulJunk .

MainIsolation . 100A

TheMain Intake position . Domestic Installation . Usually as part of the ConsumerUnit . 2392-10 (- The means to Isolate the Supply to whole Installation .
Thereis a requirement to Ensure that such Isolation beAccessible :aureola:

Tomany times I,e seen them under Stairs incupboards’ . Etc

 

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UsefulJunk .

MCBs – are designed tooperate at No more than ( 1.45 ) times their rating :aureola:

 

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►Part P – ( BR ) 2006 p/134 – Note/ 3 :19:

“ Garages “
Are considered to be Unsuitable for standard main frequencyfluorescent fittings due to ( ► Stroboscope Effects ◄ ) with rotating equipment .

[ Fluorescentlamp with ( High frequency electronic ballastsubstantially reduce this RISK . ]

 

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Inductive Loads .
Motors: Discharge lighting – Metal halide : Fluorescent or Neon:beatnik:

PartP /Building Regulation – p/15 – look in Chapter 10. 117 :19:

►The ABC,s of the BuildingRegulation . ( BR)

Part ( A ) “ Structure“ Where the positioning of ( Holes in a Joist ) Depths of chases in a masonry wallare affected .
Part( B ) “ Fire Safety “ Considers ( Smoke Alarm Systems ) & what must be done tomaintain any ( Fire Barriers ) That have been ( Breached during Work ) in a Dwelling .
Part( C ) “ Résistance to Passage of Moisture “ Looks at the ( Ingress of Moisture ) through a wall & therequirement to limit moisture build up .
Part( E ) “Résistance to Passage of Sound “ Oftenoverlooked when fitting equipment in ( Ceilings &Walls ) The sound barrier is to be maintained .
Part( F ) “ Ventilation “ Requirements for fitting of Ventilation in certain roomswithin a dwelling & the required amount of ( AirFlow ) -&-s. Big / Time ◄
Part( L ) - ( L1A & L1B ) “ Conservation of Fuel & Power . This covers both ►New& Existing dwellings ◄ for fitting orrecommending a certain amount of ( Low-energy light fixtures )

L1A / ► New Dwellings . L1B / ► Existing Dwellings .

Part( P ) – Electrical Safety ( P1 )
“Access to & use of Buildings “ Heights of Switches . Socket outlets &other equipment .

p/133. Part ( L ) – Fixed Internal Lighting . -&-s .
► One energy efficientlight fitting per four ( Fixed light fittings ) read Note[SUP]2[/SUP][SUP] [/SUP] below . Whichever is the Greater .
►one per 25m[SUP]2[/SUP] of floor area ( excluding garages ) Note[SUP]2 [/SUP]&Note[SUP]3 [/SUP]. Whichever isthe Greater .

Note[SUP]1 [/SUP].Note[SUP]2 [/SUP]. Note[SUP]3[/SUP]. p/134

 

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Rectification . in Wording . :43:

p/15- Building & Structures . with regards to SocketHeight as ( Part M ) sorry not Part P . Small Overpart on mySide .

TwoPart’s - Part / P . ( P1) “ Meaning “ Electrical Safety ( Firstly )

Part/ M . Heights of Switches. p.137 / 450mm . 1200mm

Kitchen Installation (- p/61

Rememberthat . in the ( BR) Kitchen is defined in the Building Regulations . as a room or part of a room ( -&- ) Specialinstallations . Special locations& Kitchens . p/59

( Not in Regulations BS-7671:2008 / Kitchen as Speciallocations )

 

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To Overcome Thermal Insulation Issues . 17[SUP]th[/SUP]Edition 2008 .
:beatnik:
Isi t permissible to design a Ring Final Circuit using 2.5mm[SUP]2[/SUP]cable protected by a ( 20A ) protective device .

( Yes ) if the effective CurrentCarrying Capacityof the cable is at Least ( 12.5 amp –20A x 20/32 ) So as to effectively have the same “ Deemed to comply status “
As regulation(s) give to ( 30A & 32A Ring Final Circuits )

 

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Useful Junk .
:19:

Youare Advised that it is ( Unlawful ) under the Electricity at Work Regulations 1989.

Towork on any Electrical Installation in the UK . unless you are a “ Competent Person “ ◄

TheElectricity at Work Regulations 1989 . requires persons to be Competent to prevent Danger& Injury . ( You will see this in the Regulations )
NoPerson should be Engaged in any work activity Unless . He or She possesses suchTechnical Knowledge or Experience . or is Supervised as appropriate for theWork .

TheMemorandum Qualifies Technical Knowledge or Experience as being .

i)Adequate knowledge or experience .
ii)Adequate experience of Electrical Work .
iii)Adequate Understanding of the system being worked on & practical experienceof that ( Class of System)
iv)Understanding of the Hazards that may arise during the work & thePrecautions . That . should be taken .
v)Ability to recognise at all times . whether it is Safe for Work to continue . Etc .

Useful Junk .
:19:

Copper isUsed for Underground Cabling in the transmission & Distribution Systems or (Where Weight is not an Issue ) right down toDomestic Supply ( Due to it’s LowResistivity )

 

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Firstly am NOT a Tutor . Amber .

I can offer some Guidance Only.

Amonly using this as One Example . Can you be Asked this on 2391-10 . Exams?? ( A /B ) :willy_nilly:

Explainthe Terms : 2391-10

a)Main Earthing Terminal .
b)Main Protective Bonding Conductor .
c)Exposed – Conductive – Part .

a)Main Earthing Terminal . 17[SUP]th[/SUP] Edition . p/26
TheTerminal or Bar providedfor the connection of ( Protective Conductors )including Protective Bonding Conductors . &conductors for ( Functional Earthing ) if any .to the Means of Earthing .

b) Main Protective Bonding Conductor . 17[SUP]th[/SUP]Edition . p/32
► Electrical Connection maintaining various ( Exposed Conductive Parts ) at Substantially the same Potential .

2391-10(- This involves joining together ( Metalwork )that is or may be Earthed so that it is atthe ( Same Potential) to prevent “ Danger “ Electrical Shock“ . frombetween those pieces of Metal as the Earth systemhandles a Fault .

c)Exposed Conductive Part : 17[SUP]th[/SUP] Edition. p/24
AConductive Part of equipment which can be Touched & which is NOT LIVE which can become Live when basicInsulation Fails .

17[SUP]th[/SUP]Edition . Conductive Part : of equipment which can be Touched & which is NOT LIVE which can become Live when basicInsulation Fails .

Refersto Items like :
TheMetallic Covers of electrical equipment which will normally be at Earth Potential . but which may develop a Voltage if the Fault Current goes through Equipment .