ACA Safe Isolation Test

[Sparkystevie]

Hi lads,

I'm time served electrician based in Scotland and sat my ACA two weeks ago, I failed on Safe isolation. In-between rippin me I could really do with some constructive advice to further my chances of passing. (I know i really shouldn't be failing that part of the test anyway!).

I have only ever worked on domestic and some light commercial builds, so have limited knowledge regarding motors. In fact the only motor i have ever wired was in my trade test. I think i may have made a mistake when I was asked to isolate the second of three motors which all had individual 3ph supplys from a db. The motors run in a sequence, where once motor 1 reaches a its correct speed motor two starts and so on to motor three. I followed all the procedures and isolated just that motor circuit but not the control circuit. Could this be the reason for an epic fail? I also may have given the key to the examiner at some point during the day, i cant remember if it was during the safe isolation part of the test though. I have heard that they ask for the key and then fail you for it too!

Any feedback would be appreciated, retest is looming.

Thanks

 

[Knobhead]

I’ll ask you a question. What were you supposed to work on, the starter or just the motor?

 

[Pete999]

If the motor you were asked to work on was/is part of a process, then the whole process needs to be isolated, isolating one individual motor could cause both electrical and mechanical damage, in other words permits to work would probably needed, which would involve the authorising engineers input. IMHO

 

[Farmelectrics]

giving the key to the instructor is straight fail keep it in your pocket prove testers on a proving unit twice what is aca by the way

 

[ian.settle1]

giving the key to the instructor is straight fail keep it in your pocket prove testers on a proving unit twice what is aca by the way

Key should have been put into a lockout box in some scenarios which has two keys.

 

[Farmelectrics]

yes agree if theres one there ian just thinking of when i done my am2 many years ago now was told to keep key in pocket

 

[Sparkystevie]

Thanks guys, I was asked to work on the motor no2. Not the control circuit which has a start stop. Has anyone here done this test? If so what circuits did you isolate?

 

[Plonker 3]

Have you asked you tutor what you should be dong in this instance?

 

[Pete999]

If the motor you were asked to work on was/is part of a process, then the whole process needs to be isolated, isolating one individual motor could cause both electrical and mechanical damage, in other words permits to work would probably needed, which would involve the authorising engineers input. IMHO

Did you not read this post????????????????????????????

 

[Farmelectrics]

are you talking to your self pete lol

 

[Knobhead]

If the motor you were asked to work on was/is part of a process, then the whole process needs to be isolated, isolating one individual motor could cause both electrical and mechanical damage, in other words permits to work would probably needed, which would involve the authorising engineers input. IMHO

I’m going to disagree.

With a proper Permit To Work system in place a single drive can be isolated. The emphasis is on the operator to know what can and can’t be started, likewise the tradesman should ensure his own safety. This may involve isolating drives associated with the drive in being worked on.
Some drives I’ve worked on involved 50+ locks and not all electrical. Hydraulics, pneumatic, gas, water, you name it. This is where knowing the process comes in to play.
Not all processes are single stream.

One thing you’ve all missed. Try and start the drive once it’s isolated, prove you’ve got the right isolator. It won’t be the first time the wrong isolator has been locked off.

 

[shanky887614]

I’m going to disagree.

With a proper Permit To Work system in place a single drive can be isolated. The emphasis is on the operator to know what can and can’t be started, likewise the tradesman should ensure his own safety. This may involve isolating drives associated with the drive in being worked on.
Some drives I’ve worked on involved 50+ locks and not all electrical. Hydraulics, pneumatic, gas, water, you name it. This is where knowing the process comes in to play.
Not all processes are single stream.

One thing you’ve all missed. Try and start the drive once it’s isolated, prove you’ve got the right isolator. It won’t be the first time the wrong isolator has been locked off.

he might have been failed for not isolating the control circuit, some are 240.

i would doubt it though i would have thought he would have failed for giving examiner key.

 

[Sparkystevie]

If the motor you were asked to work on was/is part of a process, then the whole process needs to be isolated, isolating one individual motor could cause both electrical and mechanical damage, in other words permits to work would probably needed, which would involve the authorising engineers input. IMHO

Sorry to summarise.. Obviously the examiner will need to prise the key from my cold dead hand this time around before he gets it back.
In regard to isolation I'm thinking isolate whatever motor circuit is asked to be isolated along with the control circuit. Therefore stopping the motors starting to run at all.. It then would not make any difference if the other two motors still had a supply as they would not be able to start.

 

[Carlosfandango]

I failed on safe isolation and made the same silly mistake as you. I asked the examiner at the resit and he said it wasn't a straight fail for not isolating the control circuit. You must have made another mistake you. I had to drive 2 hrs each way to resit the 10 minute isolation section!!!

 

[davesparks]

I am genuinely quite scared that there are electricians out there who cannot safely isolate a supply.

 

[Carlosfandango]

It's a bit different to not being able to safely isolate in the fact that it's under test conditions. That's like saying if someone fails their driving test first time they can't drive!! You can sleep easy Dave, I'm fully aware of how to isolate safely!!

 

[jamie-spark]

Hi lads,

I'm time served electrician based in Scotland and sat my ACA two weeks ago, I failed on Safe isolation. In-between rippin me I could really do with some constructive advice to further my chances of passing. (I know i really shouldn't be failing that part of the test anyway!).

I have only ever worked on domestic and some light commercial builds, so have limited knowledge regarding motors. In fact the only motor i have ever wired was in my trade test. I think i may have made a mistake when I was asked to isolate the second of three motors which all had individual 3ph supplys from a db. The motors run in a sequence, where once motor 1 reaches a its correct speed motor two starts and so on to motor three. I followed all the procedures and isolated just that motor circuit but not the control circuit. Could this be the reason for an epic fail? I also may have given the key to the examiner at some point during the day, i cant remember if it was during the safe isolation part of the test though. I have heard that they ask for the key and then fail you for it too!

Any feedback would be appreciated, retest is looming.

Thanks

I think you have miss heard him. He would have told you to isolate the motor starter so that it can be safely worked on. This requires you to THINK. there is a supply for the motor and a separate Supply for the control circuit. That requires you to isolate a both. He would have failed you because you did not understand that the starter would have still be live.

Every one sitting the ACA is given this. It's so they can see you understand. What u have been told and you have checked the circuit charts and diagrams

 

[jamie-spark]

giving the key to the instructor is straight fail keep it in your pocket prove testers on a proving unit twice what is aca by the way

Approved competence assessment

It's a one day test, required in Scotland. Passing this enables you to be graded to approved electrician status.

You can only apply to sit it,when you have had 2 years experience as a graded electrician, filled out the assessment form and job cards