Best tip I can give you for the AM2: Write everything on the back of your schedule of test results. R1+R2 at each point, Zs at each point, RCD values x1 and x5, FPC / FSC, 3 phase double PSC value, the more the better.
Ring Circuits:
Use the formulas to calculate expected R1+R2, Ring Continuity for the neutral / earth and Zs
Expected R1+R2: r1+rn /4
Expected Zs = Ze + (r1+r2)
Expected Ring continuity for Neutral: r1 = r2
Expected Ring continuity for Earth: r2 = r1 *
1.67 NOTE: Assuming you are wiring your Ring circuit in 2.5mm If not take the line and divide it by the earth. Example: 2.5/1.5 = 1.67
Cross link your ring final circuit and test each socket for the same reading or a reading within 0.05 Ohms.
Anything higher than this is typically a spur from another socket but not always.
Sometimes it's worth plugging your tester in and out a few times to clear the muck off the brass in the sockets.
Mark the outgoing and incoming ring cables in the distribution board for ease of testing later on.
Testing:
DONT FORGET TO NULL YOUR TEST LEADS AS IT LEADS TO FALSE VALUES
DO THE TESTS IN THE CORRECT ORDER:
RING CONTINUITY, CPC, IR, Zs, RCD, Polarity, RCD Test Button
IR test should be done at double the working voltage. 500V up to 500V with the exception of SELV / PELV (250V)
Make sure nothing is plugged in and any neon indicators / lamps are removed from the circuit. Switch all light switches to ensure all the cables are IR tested. A lot of people forget to do this with 2-way lighting circuits. Personally, I like to test at 230V first to make sure I get a good reading before pumping 500V down the circuit and blowing up someone's appliance.
Ensure the RCD Tester is set to the correct mA for the RCD /RCBO, 30mA usually (Could be different for you)
Safe Isolation
10 TESTS FOR 3 PHASE
L1 - E
L2 - E
L3 - E
L1 - N
L2 - N
L3 - N
L1-L2
L2-L3
L1-L3
N-E
3 FOR SINGLE PHASE
L-N
L-E
N-E
Make sure you select the GS38 compliant tester and proving unit and follow the safe isolation procedure step by step.
I could keep going but I would be here all night, maybe I will get around to making A tips and tricks guide some time
Honestly a lot of the things I am telling you, you will be told on your pre AM2 but you need to ensure you do them on the day of your exam.
Good Luck!
