Just had Refresher Course for AM2 Exam is Monday need help with PSCC and PEFC!

[RyanF]

I have just been on the refreshers course for the Am2 exam that I am about to sit on Monday coming. When the tutor was going over PSCC and PEFC. I was confused, completley thrown.

So in my head I would do:-

I would carry out this test on the Incoming Tail side of the 3 phase board?

PSCC:-

L1-N L2- N L3 - N take my highest of this test and double it. I.e 2000 Amp was my reading double it would be 4000 Amp. Make a note of this value

PEFC:-

L1- E L2-E L3 -E

Record the highest value.

Out of the two test the highest value I would record on my schedule of test sheets as my PFC?

I just need clarified as that how I would do my test for PFC.


Any links or feedback would be greatly appreciated!!!

 

[Ian1981]

Technically your highest fault current will be between phases so you would measure L1-L2 etc.
Measuring L-N and doubling the value is a rule of thumb method and errs on the side of caution.
Remember pscc is short circuit current so between phase and neutral or between phases and pefc is between phase and earth.

 

[RyanF]

Technically your highest fault current will be between phases so you would measure L1-L2 etc.
Measuring L-N and doubling the value is a rule of thumb method and errs on the side of caution.
Remember pscc is short circuit current so between phase and neutral or between phases and pefc is between phase and earth.

So I am writr in what I was saying earlier?

That PSCC

Simply test between L1- N L2- N L3-N double highest reading etc

PEFC

L1- E L2- E L3- E the highest value is noted.

I then take the highest figure out of both tests and record this on my schedule of test results etc as Ipf?

Also thanks for replying!

 

[LeeH]

PFC is the recorded worst case.

Measure between phases if your meter allows or calculate as said above. ( x 1.73)

 

[Toneyz]

Technically your highest fault current will be between phases so you would measure L1-L2 etc.
Measuring L-N and doubling the value is a rule of thumb method and errs on the side of caution.
Remember pscc is short circuit current so between phase and neutral or between phases and pefc is between phase and earth.

Just remember in bold above by Ian1981 short and sweat and you can't go wrong.

 

[Ian1981]

So I am writr in what I was saying earlier?

That PSCC

Simply test between L1- N L2- N L3-N double highest reading etc

PEFC

L1- E L2- E L3- E the highest value is noted.

I then take the highest figure out of both tests and record this on my schedule of test results etc as Ipf?

Also thanks for replying!

Yes but normally it will be your phase to neutral fault current which you double and record as your PFC for 3 phase.
Best of luck with the exam.

 

[RyanF]

Yes but normally it will be your phase to neutral fault current which you double and record as your PFC for 3 phase.
Best of luck with the exam.

Thanks for the reply and cheers Ill need it for my exam come monday like!

 

[Toneyz]

Best of luck let us know how you get on.

 

[RyanF]

Best of luck let us know how you get on.

I shall just message me on Wednesday when I find my result out.

 

[Baker1988]

The testers they used in my AM2 did not allow phase to phase testing so yes you just do line to neutral on all 3 lines and double the highest value and then line to earth on all 3 lines then which ever is higher (more than likely one of your pscc) put that down as your pfc.

Just relax mate when you go in take a bit of time to get your head round it and don't rush you have plenty of time. Also most of the people who failed in my year failed when it came to the safe isolation either they did not ask permission to isolate or they forgot to take the key out and out it in there pocket so don't forget any of that.

 

[Deleted member 26818]

Of course, if when you measure L to E, the values are higher than L to N, you double the highest value of L to E rather than the highest value of L to N.

 

[RyanF]

So another question how would you measure Zs at Main DB if you are not allowed to physically measure but, you have to calculate it using Zs=Ze+ (R1+R2) etc. But, where would you take your R1 and R2 reading etc?

Just baffled.

 

[RyanF]

The board is a three phase I forgot to mention

 

[Deleted member 26818]

So another question how would you measure Zs at Main DB if you are not allowed to physically measure but, you have to calculate it using Zs=Ze+ (R1+R2) etc. But, where would you take your R1 and R2 reading etc?

Just baffled.

You do not calculate Ze.
It is determined either by measurement or enquiry.