Discuss ***Cont../ Useful Information for Electricians & Apprentices*** in the Australia area at ElectriciansForums.net
Re: ***Cont../ Useful Information for Electricians’ & Apprentices***
559.6.1.5. Fixing of the Luminaries.
Thevast majority of light fittings are installed above head height . so clearly itis Important that the fittings are secure BS-7671 requires that the fixing for somethingas Light as a Pendent Set has to be capable ofsupporting a Mass of 5kg .
Re: ***Cont../ Useful Information for Electricians’ & Apprentices***
SorryI have to break this into two parts .
Firstlyyou should be aware there are 3 Methods / Consumer Units available . [ I will try & open the Examples for you]
Knowledgeis the greatest arsenal we have .
Thereare Single Load – RCD .
Split Load RCD & RCBO
► Just a Point to Note here . The RCD is not just a Manually OperatedInsolating Switch – Sensitive Safety Device which cuts OFFin fraction of a second if it Senses an Earth Fault.
► Question ? it is NotPractical to fit One RCD to protect the Whole House . !! Why Tripping .
Ido want to open a mine field here . “ Division of Installation “
314.Every Installation shall be divided into Circuits . as necessary to ? (i) Avoidhazards & minimize inconvenience in the event of a Fault . “ So “ One RCDat the Main incoming does not meet this criteria . ( iv)
Example)- 8 – Way 30mA DPRCD … ( 1 x RCD) IP2X .
BS-EN 60439-3……(British Standards )The country hasStandards for & reasonNOT made in China
100 Amp .
Example)- 6A ( SP) type B / MCB …. 40A ( SP ) type B / MCB → This could be used for a Shower& Power Circuit
( SP ) meaning -Single – Pole ( Line Only )
( DP ) meaning -Double – Pole ( Line& Neutral Only ) with ( L & N – Earth must be Added )
Asa Young Designer this must seem daunting . Don’t Worry
gointo the Forum& Ask Questions . We wereApprentices at one Time . Yeah .
Meaning!! BS-EN 60439-3
Regulation530.3.4. ( Consumer’s Controlgear ) Learning Curve .
Foran Installation with a 230V Single phase supplyrated up to 100A that is under the control of Ordinary Persons . Switchgear & Controlgearassemblies shall either comply with BS-EN 60439-3& Regulation 432.1. or be a Consumer Unit incorporating components &Protective devices specified by the Manufacturer complying with BS-EN 60439-3 . including the conditional Short-circuit testdescribed in Annex ZA of BS-EN 60439-3 .
Asa young Designer . if we look in O.S.G. p/17 – 2.2.5
Consumer’sControlgear
AConsumer Unit ( to BS-EN 60439-3- Annex ZA ) is for use on Single-phase Installation’s up to ( 100A ) itincludes . 530.3.4
•A Double pole isolator .
Fuses. circuit breakers or RCBOs for protection against Overload & Faultcurrents . &
•RCDs for Additional Protection against Electric Shock . ( Anything that moves . RCD it & Earth it )RCD / RCBO – remember that an RCBO is RCD/MCB .
Designer/ Electrician :
Whenspecifying Enclosures & their Accessories . it is Important to bear in mindExisting Standards to which the Products are Manufactured&/or Tested .
TheStandards are Written to Ensure CONFORMITY .Integration with other Products & Safety ofPersons & Equipment.
Thisto keep in Mind -
Overload.
ShortCircuit ↔ ( Fault Current )
EarthFault .
Wewill go there an other day { PS am not asking you to take this in all in One .am opening your eyes to things as a Young Designer }
IP4X . Rating’s on Consumer Units . “ Meaning “
RedCover - The Only Requirement of the Regulations ( BS-7671:2008) – 416.2.2. forthe Initiated ↔ ( is the TOP SURFACE of theEnclose ) IP4X/ IPXXD
(with Apertures Intended to exclude Particles of Greater than ( 1mm diameter ) To stop Dirt falling into the Enclosure
IP2X . Rating’s on Consumer Units . “ Meaning “
TheBottom & Sides ofthe Enclosures Only need to be IPXXB or IP2X ( The Testis made with a Metallic British Standard finger Test – 12.5mm diameter .
“Plain English “ FullPenetration into the Enclosure is NOT Allowed . Let ask you this ??
[Both Joints of the finger may be Bent through 90° degrees with respect to theAxis of the Finger but in ONE & the SAME direction ]
AmUsing the Wording - Finger is PushedWithout UNDUEFORCE . So there you have it . in One
Young Apprentices this is Only Guidance
Re: ***Cont../ Useful Information for Electricians’ & Apprentices***
ConsumerUnit(s)
MCBs/ RCBOs are sitting on the bottom off Buzz Bar “ Copper Bar “ Feeds Mainspower to MCBs / RCBOs
MCBs/ RCBOs are Clipped onto a DIN rail
Justa point to Note :
Wecan get – MCBs Colour coded dolly’s allow quick Visual Identification of Ratings .now – BS-EN 60898
Whatis a Split Load .
100A Main Isolator → outgoingways ?? MCB / RCBOs ( 4) Non-RCD side
RCD30mA – 80A → MCBs ( 4 ) RCD side - ( Additional Protection ) 30mA RCD Basic Protection / Touching Live Parts . ARCD is a Fixed Equipment
RCD30mA – 80A → MCBs ( 4 ) RCD side
TestingRCD buttons – Do Not Hold the button more than 2 seconds [ You are crating aFault in the RCD for Testing Purposes]
RCDs- 0° & 180° deg ( ½ - 1x – 5x )times ( This sign is for Alternating Current ≈ A.C. ) Marked on the RCD - 230V . SinglePhase
Donot Overlook – as a Tester that ( When all the Tests are Complete the Testbutton to Ensure this Functions Correctly )
Pointto Note . The 17[SUP]th[/SUP] Edition tells usto test the Button on an RCD “ But Not “Before or After Testing RCD .
Megger1552 )- an RCD Tester is an ElectronicDevice which draws current from the Supply for it’s Operation .
Thiscurrent is usually of the Order of a few mA s which is taken from Line & Neutral of the Supply under Test(s) Single-phase
For-&-s Purposes Exams’ ?? TestingResidual Current Devices ( RCD )
-&-s– i) BS-200mS ……………….. Older
-&-s– ii) BS-EN 300mS
RCDto Achieve Automatic Disconnection in the case of a Fault . ( If )
411.3.2.1.
Requires. “ in most cases “ that a Protective Device ( MCB ) shall Interrupt the Supply to a Line Conductor of a Circuit or Equipment in the eventof a Fault of Negligible Impedance between / Line Conductor& part or a Protective Conductor for the Circuit or Equipment within theAppropriate Required Disconnection Time .
“Plain English “
2392-10- TN- 0.4 seconds 41.1 – 411.3.2.2. tells us The maximum Disconnection – 41.1. shallb e applied to final circuits NOT EXCEEDING 32A [Domestic Installation(s) ]
Re: ***Cont../ Useful Information for Electricians’ & Apprentices***
Working my way Around the 17[SUP]th[/SUP] Edition :
555)- Transformers .
Thereare Only three Regulation(s) . 555.1.1. to 555.1.3. relating to Transformers asItems of Equipment .
Throughtheir Installation . subject to the generality of BS-7671:2008
Thefirst > Autotransformers & Step-up-Transformers
Autotransformers& requires where such transformer is employed & is connected to acircuit with a Neutral conductor that conductormust be connected to the common terminal of the Winding
Regulation555.1.2. Precludes .
Theconnection of Step-up Autotransformers to an ( IT ) system . in all cases wherea Step-up Transformer is used - Regulation555.1.3.calls for a Linked Switch to disconnectall Live Conductor(s) Line & Neutral – Simultaneously fromthe Supply ( DP )
Working my way around the 17[SUP]th[/SUP] Edition .
Principal Requirements for Devices for General Emergency Switching
Regulation537.4.2.3.
( Requirement )- Where practical . non-automatic device
Regulation537.4.1.2.
( Requirement )- Switching of all the live conductors( Except the Neutral where excused by Regulation 537.1.2. ) is required if there is a Risk of Electric Shock
Regulation537.4.2.1.
( Requirement )- Capableof Switching Load Current .
Regulation537.4.2.1.
( Requirement )- In the case of Motor(s) . Must be capable of switching stalled-rotor current .
Regulation537.4.1.3.
( Requirement )- To be Single-ActionDevice .
Regulation537.4.2.7.
( Requirement )- Identified as to purpose ( Appropriately Labelled )
Regulation537.4.1.3.
( Requirement )- Device to act as directly as Possible onCircuit concerned
Regulation537.4.2.5.
( Requirement )- Suitably Located
Regulation537.4.2.3.
( Requirement )- If device is used to operatecontactor controlling the circuit . Switching is requiredto de-energize coil . or another technique of suitable reliability mustbe used
Regulation537.4.2.6.
( Requirement )- If Push Button. must be the Latching OFF TYPE
Regulation537.4.2.8.
( Requirement )- Plug &Socket-outletNOTACCEPTABLE
Regulation537.4.2.4.
( Requirement )- Operating Knob . Lever or Button . PERFERABLY Colour RED .
I have shorted some stuff in wording .
Young Apprentices .
Wording– Two Words in different contents ( EmergencyStopping ) as opposed to ( Emergency Switching )
LearningCurve Here .
Emergency Switching )- devices must “ Regulation 537.4.2.1. “ must be capable of Interrupting the Supply ON LOAD
Plain English – The Full Load Current )
Emergency Switching )- requirements apply to ALL EQUIPMENT where a HAZARD may be EXPECTED in NORMAL USE.
Plain English – Located in a ReadilyAccessible Position & Operator is not put in DANGR - that could be you one day
Difference in Wording
Regulation 537.4.1.3. – Demands that an Emergency Switch Arrangement is such that onesingle action will Interrupt the appropriate supply .
Regulation 537.4.1.3. – Means for Emergency Switching shall act as directly as possible onthe appropriate supply conductors .
Regulation(s)Table 53.2 ( Restriction on Use as Isolator ) Note 3 bottom of page – read
Fused ConnectionUnit : ( FCU ) Yes / Note 3
Whatthe Regs are saying – Suitable for OFF LOAD operation Only You will be . Isolationof current using equipment . ( Fuse in Pocket ????? )
2392-10)- keep in mind you may have a TT System Except where Neutral requiresIsolation .
PS – I have been known to use lock off Spurs Unit / padlock
Testing
IsolationRequirements relating to System Types
TN-C ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-C ( Number ofPhases – Three – Phase ↔ ( Isolationrequired for ) Three Line(s) Only
TN-C–S ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-C–S ( Number of Phases – Three – Phase ↔ ( Isolation required for ) Three Line(s) Only
TN-S ( Number of Phases – Single – Phase ↔ ( Isolation required for ) Line Only
TN-S ( Number of Phases – Three – Phase ↔ ( Isolation required for ) Three Line(s) Only
TT( Number of Phases – Single – Phase ↔ (Isolation required for ) Line & Neutral
TT( Number of Phases – Three – Phase ↔ (Isolation required for ) Three Line(s) & Neutral
IT( Number of Phases – Single – Phase ↔ (Isolation required for ) Line& Neutral
IT( Number of Phases – Three – Phase ↔ (Isolation required for ) Three Line(s) & Neutral
Reply to ***Cont../ Useful Information for Electricians & Apprentices*** in the Australia area at ElectriciansForums.net
I am trying to understand how a relay system works and have designed a circuit and a ladder diagram all as attached for an 8 PIN relay, a current...
Hi all,
My question relates to the omission of overcurrent protection (specifically overload and fault protection) at the origin of an...
I've just spent an hour getting bogged down with the maths trying to work out diversity for 2 cooking appliances on the same circuit (32A MCB)...
Greetings everyone. My first post here, having read a similar thread, I understand that following the manufacturers guidance is all important...
Hi
First time with this kind of a job for me.
I have a scenario where i am planning to install about 50m 25mm TPN from a TNCS supply to supply a...