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?

 

[MrKDilkington]

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.

 

[pc1966]

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.

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).

 

[MrKDilkington]

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).

Sorry, I just realised I’m talking absolute nonsense. Ignore me.

 

[Aaron b]

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?

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.

 

[Aaron b]

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!

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.

 

[MrKDilkington]

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.

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?

 

[Aaron b]

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.

 

[MrKDilkington]

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.

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.