AM2 exam is Monday Morning Need Help with PFC testing on 3 phase and rcbo testing on lightingcircuit

[RyanF]

Hi everyone,

Not going to lie I am crapping my self for my AM2 exam on Monday Morning at 8:00. So I just need a few questions answered:- tell me if I am right or wrong.

I will be using a megger tester by the way.

PEFC testing 3 phase ( 3 probe test) :-

Clamp croc clip on the neutral bar.

L1-N -E
L2-N-E
L3- N -E

People say do to simply:-

L1-E
L2-E
L3-E

Keep a mental note of the highest figure.

PSCC on 3 phase ( 3 probe tesy but, put the neutral test lead/probe into the earth test probe so its now a 2 lead test)

Test between:-

L1-N
L2-N
L3-N

Mental note of highest figure.

Out of both test the highest figure is doubled as a rule of thumb as the fault current could occur between two phases. This fig is recorded on the test sheet as IPF.

For testing a RCBO on lighting circuit people say disconnect the load and carry out IR seperate, but also still test the RCBO tripping times but how would you do that? As in the exam you are not aloud to expose any live conductors during the live tests.

Also, when doing IR test you have to disconnect certain equipment. But, when doing the ring main there is outdoor socket with a neon fused spur in. How do you disconnect the neon out of the socket. Can you simply out the connections to this socket in a wago connector and put the socket back on, as there will be no conductors connected to the outdoor sockrt. But, I am still testing the conductors?

Any help would be great!

HELP!

 

[Toneyz]

The neon is between L & N only when the socket /spur is switched on, therefore, the socket/spur needs to be switched off. I think in the case of the unswitched fused spur with neon the fuse needs to be out as the live part of the neon is to the load side.
If you are carrying out an insulation resistance test between L & N you should disconnect from RCBO as manufactures instructions you are not exposing live conductors as this is a dead test.

 

[RyanF]

So I would remove the conductors from the RCBO which I understand. But what I am asking is how would you test tripping times of the RCBO as it will be on the lighting circuit. But you cant expose any live parts of the lighting circuit etc. Then you cant expose any live parts on the board either.

Is my PFC test procedure correct like I said above? Or is it wrong?

So would I disconnect the fuses and switch of the fused spur? When doing global IR. Also disconnect the conductors out of the RCBO and test them seperate etc.

 

[Toneyz]

You are mixing up different questions with different tests take a step back and put down your question separately if not you are confusing yourself.

 

[casperLennon]

I think you are panicking far to much. Once you get into it it’s not overly difficult. All the information is there for you

 

[RyanF]

I understand that. I just want guidance to what I am thinking of doing is correct and wont fail the sections as I dont want to resit the am2 test at all etc.

 

[casperLennon]

Have you been on -----------?

 

[Ian1981]

It’s only a 2 wire test for ze and pfc testing with a megger
The only time you need 3 wire is for a non trip zs test

 

[RyanF]

It’s only a 2 wire test for ze and pfc testing with a megger
The only time you need 3 wire is for a non trip zs test

Thats great thank you! Can I ask what setting is it set on on the Megger MFT1770 tester I think its called. As in what would you set it to on the test meter to measure PFC. As my exam is monday I dont want to fail on this.

 

[Baker1988]

When doing the ir test on the sockets just take the live out of the fuse spur and link it with wago in the back of the box to the live on the load side of the fuse spur as then you will test the full circuit as if you just turn it off or take the fuse out you will only be testing part of the curcuit as what is on the load side of the fused spur is still part of the circuit.

And you take the cables out of the rcbo then ir test the circuit on its own. As for testing the rcbo just test it at the rcbo its self as i know your not allowed to be exposed to live parts but testing at the rcbo only exposes you to the same type of terminals as it would when testing the Ze, pefc and so on you cant get a shock of them as the whole is not big enough that is perfectly fine as thats what i did.

And on the megger tester if I remember my AM2 you set it to the normal loop test and then there is a button on the tester you press which shows you the pfc reading.

 

[RyanF]

When doing the ir test on the sockets just take the live out of the fuse spur and link it with wago in the back of the box to the live on the load side of the fuse spur as then you will test the full circuit as if you just turn it off or take the fuse out you will only be testing part of the curcuit as what is on the load side of the fused spur is still part of the circuit.

And you take the cables out of the rcbo then ir test the circuit on its own. As for testing the rcbo just test it at the rcbo its self as i know your not allowed to be exposed to live parts but testing at the rcbo only exposes you to the same type of terminals as it would when testing the Ze, pefc and so on you cant get a shock of them as the whole is not big enough that is perfectly fine as thats what i did.

And on the megger tester if I remember my AM2 you set it to the normal loop test and then there is a button on the tester you press which shows you the pfc reading.

This sould like the perfect response which Ive been looking for thanks!

So let me get this right when doing the IR test on the sockets as it will be on a RCBO I am right in saying disconnect the load side from the fused spur and put the load side into the supply side of the spur. But put it back on the load side once the IR test is complete?


So by testing the RCBO how would do to that thought even though we cant remove the DB cover or any accessories as the installation will be “live”. They wont let you do it on your AM2 that way.

Also I have one more question when ensuring supply polarity did you use a voltsge indicator and test between L1- E L2- E L3 - E then L1- N L2-N L3-N expect a voltage reading but if testing N- E expect 0 volts?

 

[Ian1981]

Thats great thank you! Can I ask what setting is it set on on the Megger MFT1770 tester I think its called. As in what would you set it to on the test meter to measure PFC. As my exam is monday I dont want to fail on this.

Left hand green dial L-PE and right hand dial on Z for ZE testing

Same setting for pefc need to toggle settings on the menu option
For pscc set dial to L-N

Get yourself on YouTube and look up megger series 1700 demos.

 

[Baker1988]

This sould like the perfect response which Ive been looking for thanks!

So let me get this right when doing the IR test on the sockets as it will be on a RCBO I am right in saying disconnect the load side from the fused spur and put the load side into the supply side of the spur. But put it back on the load side once the IR test is complete?


So by testing the RCBO how would do to that thought even though we cant remove the DB cover or any accessories as the installation will be “live”. They wont let you do it on your AM2 that way.

Also I have one more question when ensuring supply polarity did you use a voltsge indicator and test between L1- E L2- E L3 - E then L1- N L2-N L3-N expect a voltage reading but if testing N- E expect 0 volts?

I would personally just take all the line/live out of the fused spur and connected them in the back with a wago thats how i did it but i suppose the way you describe would be fine aswell.

When the board is live you are allowed to take the cover off it that does not necessarily expose live parts. So you will be able to test the rcbo at the board. Are you sure the rcbo is on the lighing circuit as if I remember rightly i put the rcbo on the socket circuit and as you know you can just test the rcbo from the socket closest to the board.

And yes thats wouldnprove polarity.

 

[Simonslimline]

If the board is the Schneider acti9 isobar type i had on mine, make sure the slide-locks are on if you do a global IR test.

The weatherproof socket that is controlled by the FCU on the RFC has neons so watch out for that!

The RCBO protects the RFC and is one of the items on your list that needs to be considered when carrying out the testing There are 5 items in total to write on the Testing paperwork.

 

[RyanF]

If the board is the Schneider acti9 isobar type i had on mine, make sure the slide-locks are on if you do a global IR test.

The weatherproof socket that is controlled by the FCU on the RFC has neons so watch out for that!

The RCBO protects the RFC and is one of the items on your list that needs to be considered when carrying out the testing There are 5 items in total to write on the Testing paperwork.

Yeah Ive been informed on the refresher course that it is a acti isobar schnieder. So when doing global IR I would turn the sliders on. Turn the sliders off if I want to test certain circuits not on the global IR.