AM2 global IR testing

[Shpark]

When doing the IR testing in the AM2 is it acceptable to carry out a global IR test? Or each circuit individually?

 

[Dustydazzler]

Ummm

Don't think you would get away with a global IR test

I would opt for doing it circuit by circuit and recording the results this way

 

[richy3333]

No it isn't if it is initial verification as you have to ensure the sum of resistances meet the minimum - 1/RT = 1/R1+1/R2 etc

 

[TJ Anderson]

No it isn't if it is initial verification as you have to ensure the sum of resistances meet the minimum - 1/RT = 1/R1+1/R2 etc

They probably would require him to carry out individual tests purely to show he can.

However, a global IR value will always be lower than any of the individual circuit values because of the resistances being in parallel. If the global value is an acceptable value then all the individual circuit values will therefore also be acceptable as each one will be higher.

 

[brianmoooore]

If the global IR reads above maximum on your tester, then there's absolutely no point in doing individual tests on each circuit, since individually, they must all be over the maximum.
if the global test isn't overscale, then individual tests should be done to identify which circuits are less than perfect, even if they are well over the acceptable minimum, if for no other reason than to compare with the next test in a few years time.

 

[DrinGONatoR]

When I did my AM2 I had to test each circuit individually.

I’m not entirely sure what they ask for these days.

 

[javierm95]

Hello Mate, Ive Just passed my AM2S , you most certainly can do a global IRT test, however the following circuits require individual tests, Motor, lighting , ring main

 

[javierm95]

.

 

[Priceydyl]

Hello Mate, Ive Just passed my AM2S , you most certainly can do a global IRT test, however the following circuits require individual tests, Motor, lighting , ring main

Hi mate I’ve got my Am2 in weeks time but haven’t carried out any testing on motor circuits. Any advice on how these are done ?

 

[javierm95]

Hi mate I’ve got my Am2 in weeks time but haven’t carried out any testing on motor circuits. Any advice on how these are done ?

Hello mate, yes so it’s a delta motor you need to do a insulation resistance test on both sides of the motor, so I started at the DB to the isolator of the DOL going across earth to each phase E-L1 E-L2 E-L3 and then across phases L1-L2 L1-L3 L2-L3 you then need to perform the same sequence of tests from the motor to the bottom of the contactor, so just remember there are 6 tests for each side of the circuit, Any more questions mate just feel free to message me, all the best in your AM2!

 

[Priceydyl]

Hello mate, yes so it’s a delta motor you need to do a insulation resistance test on both sides of the motor, so I started at the DB to the isolator of the DOL going across earth to each phase E-L1 E-L2 E-L3 and then across phases L1-L2 L1-L3 L2-L3 you then need to perform the same sequence of tests from the motor to the bottom of the contactor, so just remember there are 6 tests for each side of the circuit, Any more questions mate just feel free to message me, all the best in your AM2!

Thanks for your reply mate appreciate it. Only thing I don’t really get is where you’ve said to IR from the motor to the bottom of the contractor? By this you don’t mean to IR from the motor on the floor up to the contactor above ? If so I’d want the contractor turned off ?

 

[javierm95]

Thanks for your reply mate appreciate it. Only thing I don’t really get is where you’ve said to IR from the motor to the bottom of the contractor? By this you don’t mean to IR from the motor on the floor up to the contactor above ? If so I’d want the contractor turned off ?

Thanks for your reply mate appreciate it. Only thing I don’t really get is where you’ve said to IR from the motor to the bottom of the contractor? By this you don’t mean to IR from the motor on the floor up to the contactor above ? If so I’d want the contractor turned off ?

Yes mate, so on the motor side, I tested from the motor which will test up until the bottom of the contactor which is all you need to do, the circuit will be dead and isolated so the contactor will be disengaged!

 

[desm1963]

When doing the IR testing in the AM2 is it acceptable to carry out a global IR test? Or each circuit individually?

Hi
I teach pre AM2 prep and this is what I teach and none have failed on it yet (any who failed it was for forgetting something)
Remove light from circuit / remove CO2 / Remove ring conductors from RCBO / slide slider on RCBO to off /switch central heating off at spur / make sure 3ph isolator switch is in ON position / Make sure all MCBs are in on position
Test Global (10 tests) load side of main switch
Test lighting circuit between L- E and toggle switches
Test other side of isolator to the motor
Lastly test the ring conductors separately L-N / L-E / N-E
Altogether can be done in around 2-3 minutes and you cannot fail as you have fully tested the installation.

 

[MrKDilkington]

Hi
I teach pre AM2 prep and this is what I teach and none have failed on it yet (any who failed it was for forgetting something)
Remove light from circuit / remove CO2 / Remove ring conductors from RCBO / slide slider on RCBO to off /switch central heating off at spur / make sure 3ph isolator switch is in ON position / Make sure all MCBs are in on position
Test Global (10 tests) load side of main switch
Test lighting circuit between L- E and toggle switches
Test other side of isolator to the motor
Lastly test the ring conductors separately L-N / L-E / N-E
Altogether can be done in around 2-3 minutes and you cannot fail as you have fully tested the installation.

This is great advice, thank you. When testing the ring conductors out of the RCBO do you test them together? So croc onto both lives and both neutrals, then both CPCs to both lives, and both neutrals to both CPCs?

Also is it ok to do a global IR on the board if all I’ve done is take the conductors out and switch the RCBO off? As it’ll still fire 500v into the supply side of it?

 

[MrKDilkington]

Hi
I teach pre AM2 prep and this is what I teach and none have failed on it yet (any who failed it was for forgetting something)
Remove light from circuit / remove CO2 / Remove ring conductors from RCBO / slide slider on RCBO to off /switch central heating off at spur / make sure 3ph isolator switch is in ON position / Make sure all MCBs are in on position
Test Global (10 tests) load side of main switch
Test lighting circuit between L- E and toggle switches
Test other side of isolator to the motor
Lastly test the ring conductors separately L-N / L-E / N-E
Altogether can be done in around 2-3 minutes and you cannot fail as you have fully tested the installation.

Hi, when you say you remove CO2, do you mean you take the conductors out at the alarm end and put them in wagos? That way you can test with the FCU switched on? Or test with the FCU switched off first, then test the remaining leg?

Not sure what would be the acceptable method in the AM2, but I don’t see a way to do it at 500v that means the Co2 alarm cover can stay in place.

Any guidance would be greatly appreciated!