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.
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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.
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.
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When I did my AM2 I had to test each circuit individually.
I’m not entirely sure what they ask for these days.
I’m not entirely sure what they ask for these days.
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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 ?
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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!
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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 ?
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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!
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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.
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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?
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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!
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Has anyone disconnected their bonding conductors at the pipe when doing a global IR test? Just wondering if the assessor would consider it dangerous not to, as when you test onto the earth bar the gas and water pipes become live.
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Eh?
When you IR test the CPCs must always be connected to the means of earthing (DNO earth or rod, etc) and so the connection to bonded structures should make no difference.
The reason why is the IR test is to establish that the live conductors are adequately insulated, both from the related CPC (i.e. not damaged inside a cable like T&E) but also the live conductors are not leaking to anything else, for example a nail or screw that has punctured a live conductor but not also the related CPC (e.g. nipping the edge of T&E, not though the middle).
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Sorry, I just realised I’m talking absolute nonsense. Ignore me.
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The boards are ISObar ones, there's a slider that isolates the pins to the breakers so you effectively disconnect the rcbo.
You won't need to test both ends of the ring as you will have proved the ring is continuous when doing the end to ends. There shouldn't be anything susceptible to damaged by IR testing and it's initial verification so you don't link L -N.
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The am2 doesn't reflect real life in many aspects. One of those is that testing should be done during construction. The CO2 detectors is probably wired to a quick release choc block connector so you can just unplug it. You can do so when carrying out R1+R2. It will still be IP2x with the cover off and under your control anyway. Same with the light, it will be a 2d fitting and you can unplug the ballast.
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I’m not familiar with those. So pushing the slider to off kills the supply to the RCBO, ok.
Do you know if they have a preference on how to test IR? Do they want a 10 stage global test, or can you choose to do it circuit by circuit?
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I think they will expect you to do a global IR as it will show understanding, although they can't mark you down, they may keep an eye on you if you don't appear confident.
You won't be watched continuously either but they will ask questions on how you configured it where required.
With the dol circuit, I found the easier to leave the conductors long so that I could bypass the contactor and put it back after the IR testing.
You won't be watched continuously either but they will ask questions on how you configured it where required.
With the dol circuit, I found the easier to leave the conductors long so that I could bypass the contactor and put it back after the IR testing.
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Ok thanks.
That’s a good idea with the DOL, I assumed they wanted to see you use their adapter box thing at the end of the circuit and do it in 2 parts. I was going to try and do it the way you described for R1+R2 of the motor.
Sounds like they are willing to have some flexibility with the testing procedures as long as you show understanding and competence.
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