Am2 testing section

maddad2001 · May 26, 2014

Hello I'm new to this forum, although I've read many posts as a guest previously and I'm impressed by the general positive feedback and advice the community gives. Seeing as this is probably the most important exam I will sit, I figured I'd ask for some advice.

I've been booked on the exam (am2). I'm abit nervous about certain areas of the testing and inspection part. I'm reasonable with single phase testing, but three phase I get abit stuck.

On the exam I'm worried about three phase insulation resistance, I am planning to test the entire installation in one hit, once removing co2, light fitting and rcbo components. It's the testing of the direct on line motor/starter circuit and testing at my isolator I get confused with, these legs have to be tested presumably.

With the live testing I have to test each phase separately and only record the higher of the readings for each test?

Oh and Zs, do I have to do this live for every circuit, as it somewhat contravenes EWR to do live on some circuits. I'm aware you do it on ring main and commando socket during exam as can do without exposing conductors. If I did on radial lighting circuit, does the exam allow you to ze+r1+r2 calculation for the other circuits or do I have to do each one too? its no problem just wanted clarification.

thanks for your time reading this.

Pete999 · May 26, 2014

I hope you have copy of the OSG, GN3 these publications will answer your questions

Richard Burns · May 26, 2014

maddad2001 said:
Hello I'm new to this forum, although I've read many posts as a guest previously and I'm impressed by the general positive feedback and advice the community gives. Seeing as this is probably the most important exam I will sit, I figured I'd ask for some advice.

I've been booked on the exam (am2). I'm abit nervous about certain areas of the testing and inspection part. I'm reasonable with single phase testing, but three phase I get abit stuck.

On the exam I'm worried about three phase insulation resistance, I am planning to test the entire installation in one hit, once removing co2, light fitting and rcbo components. It's the testing of the direct on line motor/starter circuit and testing at my isolator I get confused with, these legs have to be tested presumably.
Disconnect the DOL, (and all other sensitive equipment, linking past the item where necessary) perform IR test L1/L2, L1/L3, L2/L3, L1/N, L1/E, L2/N, L2/E, L3/N, L3/E.
OR you can do it in sections, test from main switch up to DOL, test cable from DOL to motor separately, same sequence of tests in each case. Record the lowest readings

With the live testing I have to test each phase separately and only record the higher of the readings for each test?
You do not say which live test you are doing but you record the worst case scenario, highest Zs/Ze, lowest IR, highest PEFC, highest PSC (doubling the line to neutral values to get the line to line PSC).

Oh and Zs, do I have to do this live for every circuit, as it somewhat contravenes EWR to do live on some circuits. I'm aware you do it on ring main and commando socket during exam as can do without exposing conductors. If I did on radial lighting circuit, does the exam allow you to ze+r1+r2 calculation for the other circuits or do I have to do each one too? its no problem just wanted clarification.
Zs can be calculated in each case, but live testing (not live working) is acceptable so they can be measured in each case as well.
thanks for your time reading this.

See above