- GS38 lists three steps when using an approved test lamp to check that a circuit is dead, list the three steps.
- What is the recommended period between calibrations of test instruments.
- Who determines the extent and limitations on a PIR?
- Name one dead test that could cause injury through electric shock and one live test that could cause injury through electric shock to persons other than the inspector, explain the reasons why?
- A system having a TN-S earthing arrangement contains a fixed electric heater that develops an earth fault, sketch the fault path for this arrangement.
- What test is required for site applied insulation?
- The following are recorded on the schedule of tests, what instruments would have been used to obtain the results? (40mS, 6.23kA, >100M ohms, 0.03 ohms)
- Why does the main earthing conductor need to be removed when carrying out a Ze (Zdb) calculation?
- What precaution could be employed when carrying out an insulation test between live and earth to prevent damage to sensitive components?
- A circuit has a Zs of 500 ohms, show your calculation as to the the RCD to be choosen.
- What is the main difference between a type B and type D MCB?
- Why when carrying out a polarity check on the incoming supply of a new installation would this not reveal an earth neutral fault?
- What disconnection time would be required for a 110 Volt system?
- Under what circumstances would a PIR not be required for an industrial installation.
- What is the requirement for obstacles used to prevent direct contact.
- Give two examples where height is used to protect against direct contact.
- What is the difference between conductive metal parts and extraneous metal parts?
- Give two examples of enviromental influences that may require an inspector to shorten the period of inspection?
- Give five reasons why a PIR may be required on domestic premises.
- Where there is likely to be parallel paths present during a PIR, apart from tests what else must be done to check the cpc?
- What does the abbreviations PEN, PME, MET mean with respect to BS 7671.
- Give three systems that are not covered by BS 7671 but need to be considered during a periodic inspection?
Tuesday, 10 July 2007
C&G 2391 Inspection and Testing Day Questions for Roger 3
A few more questions for Roger in respect of C&G 2391 Inspection and Testing
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3 comments:
The CCU is TP+N,main switch is 100Amps BS 60947, untill here everything is ok ,on CCU u have 4 circuits,one of them is the 32 Amps type B MCB which feed a 3 phase+n isolator BS 88 fuse 32Amps, thru 3x4mm single core conductors,(phase,neutral,earth),enclosed in PVC trunking, where the phase is connected on L1,neutral to neutral bar,earth to neutral earth,(L2,L3-unused),
From TP+N isolator is connected a ring final circuit thru 2.5mm conductors as follow, the 2c2.5mm for phase ring final is connected to L1, 2c2.5mm for neutral is connected neutral bar and 2c2.5mm for earth is connected earth bar
You must test this circuit and complet the test of schedule results???How must be completed the schedule of test results if the ring is faulty,the highest resistence value is 9.3ohms between live-earth???
Help???
Hi Florin
First, 'live to earth', try and say phase to CPC for the exams.
For the schedule of tests you would record the highest figure obtained which you say is 9.3 ohms in the R1+R2 column. I am assuming that the value 9.3 ohms was obtained by linking Ph1 to CPC2 and Ph2 to CPC1.
Since only a single phase is used then your test sheet would need to give L1 test results while L2 and L3 would still need to be put down but marked down as SPARE.
Hope that helps
Thank u a lot for your answer,I ve tested first the radial to isolator using method 1(temporary link in the CU),and recorded in schedule of test results(were0.11 ohms),after I ve tested the ring using the methods described in GN3,
and how I ve got the highest reading 9.3 ohms,can somebody tell me if till here I ve done right,and should I write on remarks a note about this high value, and as well in observ. and recomend. section of PIR certificate non compliance of circuit with BS 7671- code 3
Please help???
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