UK Help with AM2 assessment resit

[GUNNRYAN]

I recently finished my AM2 and unfortunately failed. The only thing I failed on was the earth fault loop impedance. I’m booking a resit but don’t want to fail it again, the procedure I carried out was.
Isolate and lock of the main switch.
Remove the main earth from terminal.
Set tester to L-PE and clip onto the earth.
Test between E-L1, E-L2, E-L3
As soon as the test is complete reteeminate the earth.
Record the highest value.
As far as I am concerned I feel I carried out this test correctly and don’t know where I went wrong, any advice would help.
[automerge]1586894024[/automerge]
Record this value as Ze.
Then calculated the Zs = Ze + (R1+R2)

 

[Ed Evans]

I recently finished my AM2 and unfortunately failed. The only thing I failed on was the earth fault loop impedance. I’m booking a resit but don’t want to fail it again, the procedure I carried out was.
Isolate and lock of the main switch.
Remove the main earth from terminal.
Set tester to L-PE and clip onto the earth.
Test between E-L1, E-L2, E-L3
As soon as the test is complete reteeminate the earth.
Record the highest value.
As far as I am concerned I feel I carried out this test correctly and don’t know where I went wrong, any advice would help.
[automerge]1586894024[/automerge]
Record this value as Ze.
Then calculated the Zs = Ze + (R1+R2)

Where did you do the assessment? if it was a training establishment ask them how to do it. What you did seems correct but you may have slightly altered the procedure when you did it real

 

[davesparks]

Record this value as Ze.
Then calculated the Zs = Ze + (R1+R2)

There's the problem, you estimated Zs by calculation instead of measuring it!

 

[JAWS]

There's the problem, you estimated Zs by calculation instead of measuring it!

Surely they cant fail him on calculating the Zs.

 

[pc1966]

Surely they cant fail him on calculating the Zs.

No idea, but what if he had been instructed to measure it?

 

[freddo]

I thought they liked people calculating the Zs now as carrying out loop tests at the circuits is deemed 'too unsafe' !!! What a pathetic world we live in.

 

[davesparks]

Surely they cant fail him on calculating the Zs.

They should be, calculating the Zs instead of measuring it is unacceptable.

 

[JAWS]

They should be, calculating the Zs instead of measuring it is unacceptable.

You are probably right Dave I just remember on my level 3 testing exam & yes its not the AM2 I asked if its ok to calculate the Zs the tutor said although he doesnt agree with it that way nothing states you can't do it this way or something to those words

 

[Ian1981]

The measure or calculation of Zs debate has been done to death so it would depend upon the specific requirements of the test centre, whether it’s acceptable to calculate it or measure it.
There’s no regulation that precludes calculating Zs however for an examination you’d expect that the requirement would be to directly measure it , to show that you know how to undertake such a test and how to interpret the results.

 

[Daniel983]

There's the problem, you estimated Zs by calculation instead of measuring it!

Hi mate, i have recently sat my AM2 exam and the assessors advise calculating the Zs value rather than measuring it because the majority of testing is on a dead circuit.

 

[GUNNRYAN]

Thanks I’ve been told by a few people who have sat there Am2 that it is acceptable to calculate the Zs the only thing my assessor did say when I rang him, without him telling me where I went wrong he said test all points when doing the Ze but does this mean I would test the neutral aswell because it is a TN-C-S system but can’t find in the guidance notes where it says to do this?

 

[davesparks]

Hi mate, i have recently sat my AM2 exam and the assessors advise calculating the Zs value rather than measuring it because the majority of testing is on a dead circuit.

This makes no sense to me.

If nothing else then a Zs test will prove that everything has been reconnected properly after any disconnections for testing have been made.
Zs testing proves the earth path all the way back to the source, it will pick up any small parts of the installation which may not have been included in the dead tests.
[automerge]1595439694[/automerge]

Thanks I’ve been told by a few people who have sat there Am2 that it is acceptable to calculate the Zs the only thing my assessor did say when I rang him, without him telling me where I went wrong he said test all points when doing the Ze but does this mean I would test the neutral aswell because it is a TN-C-S system but can’t find in the guidance notes where it says to do this?

Did he definately say Ze and not Zs? This suggests that maybe you didn't do all of the necessary loop impedance tests to be able to then establish the prospective fault current for the supply.
Did you carry out line to earth loop, line to neutral loop and phase to phase loop tests?

 

[GUNNRYAN]

I passed the PFC part of the testing so I assume I tested all the points. It just says I failed the earth fault loop but doesn’t say what part.

 

[KennyKen]

I messed up my earth loop impedance test on my AM2, 14 years ago. Back then it was a live test. Each bay was backed up by an RCCB. Although your were supposed to ask the trainer to bypass it. I forgot and even know the the test equipment had a “Dlok” function. He still failed me on it. Was you vocal throughOut your testing? I made sure he knew every step I was taking after that.

 

[lakie007]

How long did you have to wait for your results i finished Wednesday.?

I had to Measure it as it tells you to in the paper work bit harsh thou!