AM2 advice failed safe isolation

[tommyf]

Hi I am looking for advice please.

Last week I done my am2. And the only thing I failed on was safe isolation of the 3 phase circuit.

The assessor told me to safely isolate the 3 phase isolator.

So I turned of the isolator put a lock and tag on and put the key in my pocket.

I then proceeded to lift up the red cover on the 3 phase 16a socket outlet. And I used the GS 38 approved voltage indicator and put the probes into the holes on the socket.

I tested on the proving unit before and after the test and I completed all 10 tests between the conductors.


Can anyone tell me where I went wrong please?
Was I right to lock of the isolator or should I have locked of the 3phase circuit breaker on the dB?
Was I right to test at the socket with my voltage indicator or should I have took the cover of the isolator and checked on the outgoing terminals of this??


Any help would be appreciated thanks.

Tom

 

[snowhead]

It took me a few reads of the facts to twig the issue.

The assessor told me to safely isolate the 3 phase isolator. Could that have been so that it can be replaced, if so ???
So I turned of the isolator put a lock and tag on and put the key in my pocket.
Was I right to lock of the isolator or should I have locked of the 3phase circuit breaker on the dB?

 

[timhoward]

That seems likely. It's a shame that under the stress of exam conditions the questions wasn't more clearly asked, simply adding "so it can be worked on" would have clarified things.

 

[DPG]

Yeah it kind of depends how the assesor worded it. As Snowhead says, did he want the actual isolator isolating?

 

[tommyf]

It took me a few reads of the facts to twig the issue.

The assessor told me to safely isolate the 3 phase isolator. Could that have been so that it can be replaced, if so ???
So I turned of the isolator put a lock and tag on and put the key in my pocket.
Was I right to lock of the isolator or should I have locked of the 3phase circuit breaker on the dB?

So I should have locked of at the DB?

You don't think it's anything to do with how I checked it after down at the socket?

It was such awkward question that doesn't properly explain where to isolate

Thanks

 

[snowhead]

So I should have locked off at the DB?

YES.

And testing should have been at the isolator as it's that that would be worked on.

Other possibles, test with power to the socket before isolating to prove you have control.
If testing a socket be sure that the socket doesn't need a plug in it for the pins to be live, thinking sockets with interlocks to it's own isolator or Legrand Martin Lunel sockets, where twisting the plug powers up the socket.

 

[Gokul Nepal]

Did you actually switch off all the other circuit breakers before you switched off the main three phase isolator. my guess.

 

[norfyz]

You should've isolated at the 3ph breaker in the DB.

The instructions do state that you are to isolate the 3ph circuit so the isolator can be worked on, I clearly remember reading it. With pressure and time constraints this can be mis-read which is a little bit sneaky on their part.

 

[desm1963]

Hi I am looking for advice please.

Last week I done my am2. And the only thing I failed on was safe isolation of the 3 phase circuit.

The assessor told me to safely isolate the 3 phase isolator.

So I turned of the isolator put a lock and tag on and put the key in my pocket.

I then proceeded to lift up the red cover on the 3 phase 16a socket outlet. And I used the GS 38 approved voltage indicator and put the probes into the holes on the socket.

I tested on the proving unit before and after the test and I completed all 10 tests between the conductors.


Can anyone tell me where I went wrong please?
Was I right to lock of the isolator or should I have locked of the 3phase circuit breaker on the dB?
Was I right to test at the socket with my voltage indicator or should I have took the cover of the isolator and checked on the outgoing terminals of this??


Any help would be appreciated thanks.

Tom

Hi Tom
You failed because you should have locked off the 3phase MCB / protective device. Then removed the cover of the isolator and tested at the incoming supply of the isolator. By going to the 3phase socket you are not confirming the isolator is correctly isolated. hope that clears up the issue

 

[jaffa183]

Hi I am looking for advice please.

Last week I done my am2. And the only thing I failed on was safe isolation of the 3 phase circuit.

The assessor told me to safely isolate the 3 phase isolator.

So I turned of the isolator put a lock and tag on and put the key in my pocket.

I then proceeded to lift up the red cover on the 3 phase 16a socket outlet. And I used the GS 38 approved voltage indicator and put the probes into the holes on the socket.

I tested on the proving unit before and after the test and I completed all 10 tests between the conductors.


Can anyone tell me where I went wrong please?
Was I right to lock of the isolator or should I have locked of the 3phase circuit breaker on the dB?
Was I right to test at the socket with my voltage indicator or should I have took the cover of the isolator and checked on the outgoing terminals of this??


Any help would be appreciated thanks.

Tom

Did you ask for permission to isolate?

 

[123]

Almost a year old thread, would like to think he has now passed his AM2 and is a qualified spark

 

[desm1963]

Did you ask for permission to isolate?

Hi Tommyf
You failed because you should have locked the 3phase MCB/protective device. Then you remove the isolator cover (not the socket) and should have tested at the supply side of the isolator. By going to the socket and removing the cover you are not confirming that the isolator was fully tested for isolation.
Hope this clears this up
Des