**City & Guilds 2392-10 Course notes**

[amberleaf]

Inspection & Testing Methods : City & Guilds 2392-10 fundamental Course

( Before : Test prior to the Installation being Energized )

Test – Sequence of Tests ,

( 1 ) Continuity of Bonding conductors and Protective conductors’ : Low reading ohmmeter 
( 2 ) Continuity of Ring Final Circuit Conductors’ : Low reading ohmmeter 
( 3 ) Insulation Resistance : 500V dc : 1.0m TN-C-S systems 0.4 s under 32A
• Instrument setting used for conducting insulation resistance Tests ( m ) C/G
( 4 ) ” Dead Test ” Polarity of each circuit : *** Low reading ohmmeter 
• Which one of the following ” Dead Tests ” should also be repeated ” Live” ( Polarity ) C/G

“ After ” : Test Following Installation being Energized :

( 1 ) Earth fault loop impedance : ( Ze ) ( Zs )
( 2 ) Live polarity of Supply : ***
( 3 ) Prospective fault current : ( PFC ) ***
• PSCC : the expected current during a short-circuit fault the ( Prospective Short- Circuit Current ( PSCC ) C/G

( 4 ) Functional testing : ( RCD Testing )
• Which one of the following devices is Not designed to protect against Overload Currents C/G
• This is Designed to protect against Earth Leakage Currents Only ( RCD )

“Continuity of Bonding Conductors “
( 1 ) Safely isolate the Supply :

( 2 ) Disconnect one end of the Conductor , preferably the end at the Consumer unit :

( 3 ) ( Null out test Leads ) or ( Record and remember to Subtract from End Result )

( 4 ) Connect one test Lead at the Consumers units Disconnected end :

( 5 ) Connect the other test Lead to Metal work of which the Conductor you are Testing is Connected to
( Ensure any painted Metal work has been Scratched off , to make a Solid connection )
By not Connecting it to the Clamp will prove that the Integrity of that Clamp is Efficient enough / Correct BS-951 :

( 6 ) Test – the Result will give the Total resistance of the Conductor :
( Remembering to Subtract the Test Leads Resistance , if not Previously pulled out )

( 7 ) Re – Connect Bonding Conductor :

Documents :
( a ) Electricity at Work Regulations 1989 :
( b ) Health and Safety Executive Guidance Note GS38 :
( c ) BS7671 – Requirements for Electrical Installations :

Instruments
( Before : Test prior to the Installation energized )
( a ) Continuity of protective conductors – Low reading ohmmeter 
( b ) Continuity ring final circuit – Low reading ohmmeter 
( c ) Insulation resistance – Insulation resistance tester M
( d ) Live polarity – GS38 compliant voltmeter or test lamp
( e ) multi - probe test instrument : Earth electrode tester
Insulation Resistance 230V Installation : M
500V
250 dc 0.5 M
500 dc 1 M
RCD tests :
( a ) Earth loop impedance determines that an earth fault loop path exists ( Earth loop impedance tester )
( b ) Functional test determines that the RCD will actually operate in the event of a fault – electro-mechanical test using the ‘T’ button
( c ) Max test current for 100mA RCD is 100mA

IP Codes :
Intermediate barriers – IP2X or IPXXB
Horizontal top surfaces

( i ) Continuity and “ R2 “

( ii ) Earth fault loop impedance . ( Zs ) is the Measurement of the whole of the Fault path

Columns ( 6 ) and ( 7 ) of the Schedule of test Results page : 341
Require Measurements of ( R1 + R2 ) or R2 to be noted , may be simply a continuity test To ensure that the Line
and the Protective Conductors’ are Continuous ,

( R1 + R2 ) may also be recorded : ( Checking that the Earth Fault Loop Impedance is Sufficiently Low : and R2
: The requirements of the alternative method are met – see regs : page 243 ?


( Single phase TN-C-S installation has a Ze of 0.015 ohms. Calculate Prospective fault current :

Appendix 3 of BS7671 gives this relationship:

Uo
Zs = ------ where Uo = open circuit voltage at transformer , and is taken as 230 V
Ia

Uo 230
So the calculation is : Ia = ------ = -------- = 15333. kA ( 16 kA
Zs 0.015

 

[amberleaf]

Regulations 12 } Means for Cutting off the Supply and for Isolation {

● (i ) Where necessary to Prevent Danger , suitable means shall be Available for Cutting off the Supply e.g.
Test such as Continuity of Protective Conductors and Insulation Resistance are carried out on “ DEAD “ Installations or it
Circuits , it is therefore Necessary to carry “ OUT “ Safe Isolation procedure prior to “ TESTING “

Regulations 13 } Precautions for Work on Equipment made Dead {

● (i ) Adequate precautions shall be taken to prevent Electrical Equipment , which has been made “ DEAD “in order to
Prevent Danger while work is carried out on or near that Equipment , from becoming Live e.g. carry out a Safe Isolation procedure

Regulations 14 } Work on or Near Live Conductors’ {

● (i ) No person shall be Engaged in any work activity on or Near any Live Conductors unless it is “ UNREASONABLE “
For them to be Dead , it is Reasonable in all Circumstances or suitable Precautions are taken to Prevent injury e.g.
Live working only in Extreme Circumstances

Regulations 15 } Working space , Access and Lighting {

● (i ) For the purpose of enabling injury to be Prevented , adequate working space , adequate means of Access , and
Adequate lighting shall be provided at all Electrical Equipment in Circumstances with may give rise to Danger e.g. temporay lighting

Regulations 16 } Persons to be Competent to prevent Danger and Injury {

● (i ) No person shall be Engaged in any work activity where Technical Knowledge or Experience is Necessary to prevent Danger
Or , where Appropriate , injury , unless he Possesses such knowledge or Experience , or is under such Degree of Supervision as may be Appropriate having regard to the nature of the work , e.g. NICEIC registered , ECS (JIB ) card or Supervised

Regulations 12 } Means for Cutting off the Supply and for Isolation {

● (i ) Where necessary to Prevent Danger , suitable means shall be Available for Cutting off the Supply e.g.
Test such as Continuity of Protective Conductors and Insulation Resistance are carried out on “ DEAD “ Installations or it
Circuits , it is therefore Necessary to carry “ OUT “ Safe Isolation procedure prior to “ TESTING “

Regulations 13 } Precautions for Work on Equipment made Dead {

● (i ) Adequate precautions shall be taken to prevent Electrical Equipment , which has been made “ DEAD “in order to
Prevent Danger while work is carried out on or near that Equipment , from becoming Live e.g. carry out a Safe Isolation procedure

Regulations 14 } Work on or Near Live Conductors’ {

● (i ) No person shall be Engaged in any work activity on or Near any Live Conductors unless it is “ UNREASONABLE “
For them to be Dead , it is Reasonable in all Circumstances or suitable Precautions are taken to Prevent injury e.g.
Live working only in Extreme Circumstances

Regulations 15 } Working space , Access and Lighting {

● (i ) For the purpose of enabling injury to be Prevented , adequate working space , adequate means of Access , and
Adequate lighting shall be provided at all Electrical Equipment in Circumstances with may give rise to Danger e.g. temporay lighting

Regulations 16 } Persons to be Competent to prevent Danger and Injury {

● (i ) No person shall be Engaged in any work activity where Technical Knowledge or Experience is Necessary to prevent Danger
Or , where Appropriate , injury , unless he Possesses such knowledge or Experience , or is under such Degree of Supervision as may be Appropriate having regard to the nature of the work , e.g. NICEIC registered , ECS (JIB ) card or Supervised

“ Polarity “ City & Guilds 2392-10 Course Notes Revision

3.20 { State the reasons for Tests to Confirm Polarity }

● Polarity tests are carried out to ensure that all fuses , single pole switches , MCBs etc are Connected in the
Line Conductor , the Centre Contact of Edison Screw lamp holders must be Connected to the Line -
Conductor ( except E14 & E27 lamp holders ) 612.5.2 !!
Also Accessories such as Sockets Outlets must have the Line Connection Connected to the Line side of the Supply

● When Energised Polarity should be Confirmed during any Line Testing ↔ Describe the methods of Testing used to
Identify Correct Polarity

“ Polarity “

3.21 When carrying out Continuity of Protective Conductors’ ( R1 + R2 ) Testing the Polarity of the Final Circuit
is also Confirmed , When Taking a Reading for “ R1 “ + R2 The Control Switch should then be Switched OFF
if the Reading goes from a Low value to a High value it Confirms Polarity is Correct !! 2000 !! on the meter


“ Polarity “

3.22 { State the reasons Confirming Correct Polarity following Initial Energising of Installations }

● Although Polarity of the Final Circuits have been Confirmed when Carrying out Continuity of the Protective Conductor
Testing the Polarity of the Supply and Consumer Unit or Distribution board Connections have not BEEN Confirmed ,
This Should Confirmed using an Approved Voltage Indicator by Checking there is Voltage between Lines
( Three Phase ) Voltage between !! Line(s ) and Neutral !! and no voltage between !! Earth and Neutral !! Polarity
Should also be Confirmed before Carrying out any Live Testing of Final Circuits ,
This is usually Achieved with Polarity Indication on the Test Instruments such as Multifunction Instruments’

● You can get the Odd Three Phase on a Domestic Installation , it has been knowing to happen ♫♫♫♫

 

[amberleaf]

Insulation Resistance City & Guilds 2392-10 Course Notes Revision

3.14 State the precautions’ to be taken before Testing Insulation Resistance in Terms of :

● Isolation of the Circuits and Equipment ,
● Voltage Sensitive Equipment ,
● Electronic Components ,

→ Isolation of Circuits and Equipments ←

( a ) The following procedure for Safe Isolation should be taken

● Select a GS38 approved Test Lamp or Voltage Indicator :

● Check Test Lamp / Voltage Indicator is Functioning Correctly be Testing on a know Supply or Proving Unit , :

● Determine whether Isolation is for whole Installation or Specific Circuit( s) :

● Locate means of Isolation ensuring there is no Standby Supply Arrangement :

● Switch off and Lock off Isolation Device( s) e.g. fuse switch , Isolator , MCB etc :

● Verify , using Test Lamps / Voltage Indicator , Circuit( s) are Dead between Line( s) Neutral & Earth :

● Erect Warning Notice( s) in Appropriate Position( s) e.g. at Consumer Unit :

● Re Check Test Lamps / Voltage Indicator is still functioning Correctly :

● Retain key( s) for Locking off Devices :

( b ) Before Carrying out Insulation Resistance Testing it must be Established that there is No voltage
Sensitive Equipment Connected that may be Damaged or Malfunction because of the Test voltage Applied ,
There may be Computers , Programmable Logic Controllers ( PLCs ) Programmers etc the Equipment would
either have to be Disconnected During Test , or Insulation Test with Line( s) & Neutral connected together
and Test between these and the Protective Conductor

( c ) Before Carrying out Insulation Résistance Testing it must also be Established that there is no Electronic
Components that may be damage or Malfunction because of the Test voltage Applied,
One Example of this is a Lamp Dimmer this would have to be Removed during Test and the
Switch wires Connected together

3.15 Describe methods of Testing Insulation Résistance
→ Before Carrying out Insulation Résistance Testing ensure that ←

● All Lamps , are Capacitors and loads are Disconnected ,
● Voltage Sensitive Electronic Equipment such as Dimmer switches , touch switches , delay timers , power controllers ,
Fluorescent lamp starters , Emergency lighting , RCDs e.g. are Disconnected ,

● There is No Electrical Connections between Line( s) Neutral & Earth

City & Guilds 2392-10 Course Revue
“ Earth Fault loop impedance tester “ { Before }

● Before Carrying out this Test the Supply Earthing Conductor must be Disconnected from Any Parallel Paths
Such as Main Equipotent Bonding Arrangements for “ Gas “ Water “ etc ← ← ← * C/G

* Earth Electrode Testing * Measured Resistance should Not Exceed 100 Ω ● ← ← ← *

● Supply Cable Line and Protective Conductor and Sub-Station Transformer Windings
The reading Obtain should be No Greater than → 21Ω ← Distributor TT Supply O/S/G P-11 *

“ Earth Electrodes “ { Earth Electrode Testing ● Measured Resistance should Not Exceed 100 Ω - } 50v div 30mA = 1666 Ω 41.5 ←


{ Describe the method of testing Earth Electrodes Resistance using an Earth Fault Loop Impedance Tester }

Earth Electrode Testing can be carried using an Earth Fault Loop Impedance Tester given a Reading in Ohms Ωs

} Test Sequence is as Follows {

● Switch OFF Main Supply to Installation C/G all 6 Items

● Disconnect Main Earthing Conductor

● Ensure Instrument is Set on the Earth Fault Loop Impedance range

● Connect Instrument Test Leads to Supply Line , Neutral ( if required ) and Main Earthing Conductor

● Confirm Polarity is Correct on Test Instrument ( a must ) ← ← ← *

● Take a reading of Earth Fault Loop Impedance ( Ze )

 

[acat]

Fantastic job thank you for your efforts






Chris

 

[pushrod]

All copied to word, thanks again Amberleaf.

 

[gunner]

echo the words of others,truly fantastic piece of work

 

[tscheung]

very helpful,
thanks a lot

 

[brucelee]

hi amberleaf
as per usual great info and will surely be a great deal of people like myself cheers for all your efforts mate

 

[antimatter]

Re: City & Guilds 2392-10 Course notes

Unit 101 1.4

( 3 ) BS-7079 gives Requirements for ?
( a ) Design and installation of temporary ac distribution systems <<<<<<<
( b ) Solar Voltaic ( pv ) power supply systems
( c ) Telecommunications’ systems
( d ) Exhibitions , shows and stands

Sorry amberleaf I think you mean Bs 7909 as BS 7079 deals with the preperation of steel substrates before application of paints and related products

Cheers

 

[antimatter]

Great post though, Thanks.

 

[kung]

Great post Mr L
As usual great info for anyone pre exam !
Regards
Kung.

 

[nhanvu]

Very Appreciated to EVERYONE!
Great HELP!!!!

 

[SLSpark]

looking on doing the 2391 course can anyone help or give advice etc

 

[brucelee]

Hi mate

the 2391-10 lv3 as 2391-20 lv3 are now closed to new entrants

you would now have to do the 2394 initial verification and 2395 Periodic inspection of existing installationsthese are lV3 and the 2396 is design and verification now lv4
so basically the 2391-10 has now been split into 2 which means paying double what you paid for 2391-10

If you go on C&G website and type in electrical qualifications or 2394 , 2395 etc it will have al the info the if you put your postcode it will give yo a lsit of providers statring at the nearest to your postcode

 

[spencerwalters]

thanks

 

[spencerwalters]

What is the rating of the over current device use on lighting circuit?