AM2 testing

[kingkai]

Hi everyone,

a few questions here

Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result on the test sheet then take the PSCC - Then which ever was highest out of the PEFC and PSCC use that for my PFC but double the answer?
Obviously when doing the Ze the board is isolated but when it comes to doing the PSCC do I re energise the board and then do the test? and do all breakers have to be on?

Also on the schedule of results there is a Zs at Db, I think I have confused myself on this. In the AM2 I'm guessing the board is simulating that it is the only board of the installation therefore will only need to do a Ze?
Is the Zs at Db for when you have another DB fed off another?

when polarity testing its just a simple voltage check between phases - do I check phase rotation while doing this as well ?
And do I have to do Phase rotation on the three phase equipment before the Zs?


many thanks

 

[Pete999]

Hi everyone,

a few questions here

Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result on the test sheet then take the PSCC - Then which ever was highest out of the PEFC and PSCC use that for my PFC but double the answer?
Obviously when doing the Ze the board is isolated but when it comes to doing the PSCC do I re energise the board and then do the test? and do all breakers have to be on?

Also on the schedule of results there is a Zs at Db, I think I have confused myself on this. In the AM2 I'm guessing the board is simulating that it is the only board of the installation therefore will only need to do a Ze?
Is the Zs at Db for when you have another DB fed off another?

when polarity testing its just a simple voltage check between phases - do I check phase rotation while doing this as well ?
And do I have to do Phase rotation on the three phase equipment before the Zs?


many thanks

Hasn't all this been explained to you by the Tutor during the course, if not I would ask for my money back.

 

[davesparks]

Zs at the DB is different to Ze even when there is only one DB.
When you measure Ze you are only measuring the efli via the means of earthing, whne you measure Zs you are measuring the efli of the means of earth plus any other parallel return path in the installation.

Think about what exactly is being measured for each test and it should become obvious what should or should not be connected for each test.

For PSCC check what the tester you are supplied with is capable of testing, you should be able to ask the assessor whether the tester is suitable for/capable of measuring directly the line to line loop impedance, if it isn't then you will have to calculate the value using the measured line to neutral value.

 

[kingkai]

Hasn't all this been explained to you by the Tutor during the course, if not I would ask for my money back.

I haven't paid a penny lol

Yes it has been explained by the tutor a long time ago, and I have not had any practical experience in doing these tests. A lot of the sites I work at I am not allowed to do any testing at all.

So can you tell me if any of what i said is correct because i believe it to be so?

thanks you

 

[kingkai]

Zs at the DB is different to Ze even when there is only one DB.
When you measure Ze you are only measuring the efli via the means of earthing, whne you measure Zs you are measuring the efli of the means of earth plus any other parallel return path in the installation.

Think about what exactly is being measured for each test and it should become obvious what should or should not be connected for each test.

For PSCC check what the tester you are supplied with is capable of testing, you should be able to ask the assessor whether the tester is suitable for/capable of measuring directly the line to line loop impedance, if it isn't then you will have to calculate the value using the measured line to neutral value.

Thank you for that mate nice one

 

[Pete999]

I haven't paid a penny lol

Yes it has been explained by the tutor a long time ago, and I have not had any practical experience in doing these tests. A lot of the sites I work at I am not allowed to do any testing at all.

So can you tell me if any of what i said is correct because i believe it to be so?

thanks you

Have you tried access to the Trainee area of this Forum? lots of info to be gained there, ask one of the Moderators for permission. Not having any experience with the AM2 mate and the methods they preach I can't be sure my answers would be commensurate with this course. May be "Westward10" could help with access.

 

[Deleted member 105166]

I haven't paid a penny lol

Yes it has been explained by the tutor a long time ago, and I have not had any practical experience in doing these tests. A lot of the sites I work at I am not allowed to do any testing at all.

So can you tell me if any of what i said is correct because i believe it to be so?

thanks you

You need to get some practical experience, watching and working alongside an electrician on a few jobs.

 

[Simonslimline]

PEFC is measured with the earthing conductor connected to the means of earthing. The reason it is disconnected when carrying out the Ze is so parallel paths are not included in the test. Are you doing the Am2 at Culham?

 

[kingkai]

PEFC is measured with the earthing conductor connected to the means of earthing. The reason it is disconnected when carrying out the Ze is so parallel paths are not included in the test. Are you doing the Am2 at Culham?

Great thank you for that. Yes doing the AM2 at Culham.

 

[davesparks]

PEFC is measured with the earthing conductor connected to the means of earthing. The reason it is disconnected when carrying out the Ze is so parallel paths are not included in the test. Are you doing the Am2 at Culham?

To be precise, the PEFC is measured with the installation connected to the means of earthing, not just the earthing conductor.
Most test links on earth bars disconnect the earthing conductor from the installation, not the earthing conductor from the means of earthing.

And to be even more pedantic the PEFC isn't measured, the loop impedance is measured and the PEFC is calculated from that.

 

[Toneyz]

Have you tried access to the Trainee area of this Forum? lots of info to be gained there, ask one of the Moderators for permission. Not having any experience with the AM2 mate and the methods they preach I can't be sure my answers would be commensurate with this course. May be "Westward10" could help with access.

Pete, you had some good youtube videos by Chris Karcher you maybe could repost these are very good for the O.P.
Kingkai you need to get some practical experience on testing

 

[Pete999]

Hi everyone,

a few questions here

Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result on the test sheet then take the PSCC - Then which ever was highest out of the PEFC and PSCC use that for my PFC but double the answer?
Obviously when doing the Ze the board is isolated but when it comes to doing the PSCC do I re energise the board and then do the test? and do all breakers have to be on?

Also on the schedule of results there is a Zs at Db, I think I have confused myself on this. In the AM2 I'm guessing the board is simulating that it is the only board of the installation therefore will only need to do a Ze?
Is the Zs at Db for when you have another DB fed off another?

when polarity testing its just a simple voltage check between phases - do I check phase rotation while doing this as well ?
And do I have to do Phase rotation on the three phase equipment before the Zs?


many thanks

Kingkai, you could always go to the internet and search Chris Kerchar videos, I'll post one up for you to sample

There are many more to choose from enjoy

 

[Simonslimline]

To be precise, the PEFC is measured with the installation connected to the means of earthing, not just the earthing conductor.
Most test links on earth bars disconnect the earthing conductor from the installation, not the earthing conductor from the means of earthing.

And to be even more pedantic the PEFC isn't measured, the loop impedance is measured and the PEFC is calculated from that.

My megger has loop and pfc setting. Glad you know better though as ever.

I could of worded my post better.

 

[Grant1987]

Hi everyone,

a few questions here

Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result on the test sheet then take the PSCC - Then which ever was highest out of the PEFC and PSCC use that for my PFC but double the answer?
Obviously when doing the Ze the board is isolated but when it comes to doing the PSCC do I re energise the board and then do the test? and do all breakers have to be on?

Also on the schedule of results there is a Zs at Db, I think I have confused myself on this. In the AM2 I'm guessing the board is simulating that it is the only board of the installation therefore will only need to do a Ze?
Is the Zs at Db for when you have another DB fed off another?

when polarity testing its just a simple voltage check between phases - do I check phase rotation while doing this as well ?
And do I have to do Phase rotation on the three phase equipment before the Zs?


many thanks

Hi mate sounds like you have good understanding of electrics and on right track don’t over complicate things and get yourself worked up. You measure you’re Ze and PFC at consumer unit with the main earth taken out of earth bar at DB put a crocodile clip on that earth and then put your neutral and live (line) conductor at main breaker with the probes on them as far as I’m aware that’s what the requirement is to measure you’re Ze and PFC on am2 although your tutor should guide you on right path you won’t have 3 phase as far as I’m aware on am2 bit risky for them to incorporate that

 

[davesparks]

My megger has loop and pfc setting. Glad you know better though as ever.

I could of worded my post better.

Yes it has the setting and displays the values, mine does too, but it doesn't measure the PFC, it calculates it from the measured loop impedance and voltage. This is made clear in the manual.

To actually measure the PFC you would have to allow that current to flow, and there's no way a meter is going to survive even a modest PFC flowing through it.

 

[Deleted member 105166]

there's no way a meter is going to survive even a modest PFC flowing through it.

...nor the test leads and (most importantly) nor the person whose neck said meter is hanging around!

 

[davesparks]

...nor the test leads and (most importantly) nor the person whose neck said meter is hanging around!

As much as I know my tester is designed with safety in mind I always avoid carrying out a live test with it hanging round my neck.

 

[Grant1987]

Yes it has the setting and displays the values, mine does too, but it doesn't measure the PFC, it calculates it from the measured loop impedance and voltage. This is made clear in the manual.

To actually measure the PFC you would have to allow that current to flow, and there's no way a meter is going to survive even a modest PFC flowing through it.

As much as I know my tester is designed with safety in mind I always avoid carrying out a live test with it hanging round my neck.

Hopefully whatever is around your neck is not a conductor that would hurt lol im pretty sure no manufacturer of testers would design anything to conduct electric around your neck

 

[Deleted member 105166]

Hopefully whatever is around your neck is not a conductor that would hurt lol im pretty sure no manufacturer of testers would design anything to conduct electric around your neck

Obviously, although what @davesparks said makes good sense and I'll certainly adopt it, as if a tester is going to fail and go 'bang', I'd rather that happen with it anywhere other than against my own body!

 

[Sparks82]

Hi I did my am2 last week
Ze just measure each phase to earth and record the highest reading
We were told didn’t need to do pefc just pscc done same as ze except test between each phase and neutral then double highest one and record reading, were ever it says ze db just write your ze in.
You do polarity between all phases to earth, all phases to neutral, between all phases and neutral to earth, ze, pfc, phase sequence at board, then power on, phase rotation at each 3 phase circuits, rcd test then calculate your zs for each circuit.
Do functional tests and u have to write all calculations down

 

[telectrix]

Obviously, although what @davesparks said makes good sense and I'll certainly adopt it, as if a tester is going to fail and go 'bang', I'd rather that happen with it anywhere other than against my own body!

i trust my tester to not kill me even if it went bang and blew itself to bits.

 

[Joshhosk]

Hi I did my am2 last week
Ze just measure each phase to earth and record the highest reading
We were told didn’t need to do pefc just pscc done same as ze except test between each phase and neutral then double highest one and record reading, were ever it says ze db just write your ze in.
You do polarity between all phases to earth, all phases to neutral, between all phases and neutral to earth, ze, pfc, phase sequence at board, then power on, phase rotation at each 3 phase circuits, rcd test then calculate your zs for each circuit.
Do functional tests and u have to write all calculations down

Is this using 3 lead high?

 

[Sparks82]

Ask them before you do the test. Where I did it they had a switch where they could bypass the rcd when testing in the bays

 

[Joshhosk]

Ask them before you do the test. Where I did it they had a switch where they could bypass the rcd when testing in the bays

ive got my am2 next week im pretty much comfortable with everything apart from live testing as ive done it once about 2 years ago. I'm unsure on tester settings 2 lead low/ 2 lead high / 3 lead high /3 lead low

 

[Sparks82]

For ze if they can bypass the rcd then 2 lead high if not then 3 lead low. Zs should all be calculated

 

[davesparks]

ive got my am2 next week im pretty much comfortable with everything apart from live testing as ive done it once about 2 years ago. I'm unsure on tester settings 2 lead low/ 2 lead high / 3 lead high /3 lead low

High current tests should be used whenever possible as they give the most reliable result.
A 3 lead low current test should only be used when the presence of an RCD in a circuit prevents high current tests.
A 2 lead low current test will be the least reliable and should only be used when no other method is possible.

 

[Joshhosk]

High current tests should be used whenever possible as they give the most reliable result.
A 3 lead low current test should only be used when the presence of an RCD in a circuit prevents high current tests.
A 2 lead low current test will be the least reliable and should only be used when no other method is possible.

fantastic thats really helpful! presence of a rcd in a circuit? the its going to be a 3p&n mainswitch. I've been told we are testing from the supply side of the mainswitch so it wouldnt matter about the presence of rcds?
[automerge]1569866453[/automerge]

High current tests should be used whenever possible as they give the most reliable result.
A 3 lead low current test should only be used when the presence of an RCD in a circuit prevents high current tests.
A 2 lead low current test will be the least reliable and should only be used when no other method is possible.

thanks buddy!!

 

[Grant1987]

fantastic thats really helpful! presence of a rcd in a circuit? the its going to be a 3p&n mainswitch. I've been told we are testing from the supply side of the mainswitch so it wouldnt matter about the presence of rcds?
[automerge]1569866453[/automerge]

thanks buddy!!

Yes as far as I’m aware you’re correct I’ve always measured my Ze and PFC at supply side of main switch with a 3 lead High setting so Rcds should not come into effect. I take the main earth out of the earth bar and do it that way to avoid parellel paths and give true reading.

 

[davesparks]

Yes as far as I’m aware you’re correct I’ve always measured my Ze and PFC at supply side of main switch with a 3 lead High setting so Rcds should not come into effect. I take the main earth out of the earth bar and do it that way to avoid parellel paths and give true reading.

A high current test is a 2 wire test, it doesnt need the additional neutral connection that the low current tests require.
[automerge]1569876563[/automerge]
K

fantastic thats really helpful! presence of a rcd in a circuit? the its going to be a 3p&n mainswitch. I've been told we are testing from the supply side of the mainswitch so it wouldnt matter about the presence of rcds?
[automerge]1569866453[/automerge]

thanks buddy!!

If the supply to the board has an RCD further upstream, which it may do in a college enviroment, then you would still have to use a low current test. You will have to ask the person supervising your AM2 about this as it will vary between test centres, as someone mentioned earlier some of them will be able to bypass the RCD temporarily for the test.

 

[Grant1987]

A high current test is a 2 wire test, it doesnt need the additional neutral connection that the low current tests require.
[automerge]1569876563[/automerge]
K

If the supply to the board has an RCD further upstream, which it may do in a college enviroment, then you would still have to use a low current test. You will have to ask the person supervising your AM2 about this as it will vary between test centres, as someone mentioned earlier some of them will be able to bypass the RCD temporarily for the test.

Right ok I

A high current test is a 2 wire test, it doesnt need the additional neutral connection that the low current tests require.
[automerge]1569876563[/automerge]
K

If the supply to the board has an RCD further upstream, which it may do in a college enviroment, then you would still have to use a low current test. You will have to ask the person supervising your AM2 about this as it will vary between test centres, as someone mentioned earlier some of them will be able to bypass the RCD temporarily for the test.

Right ok so just to clarify are the results I’m obtaining wrong by carrying out the 3 lead test (high) with the neutral?

 

[davesparks]

Right ok I

Right ok so just to clarify are the results I’m obtaining wrong by carrying out the 3 lead test (high) with the neutral?

I think you have missed my point, a standard loop impedance test (high current test) is a two wire test.
If you you connect a third test lead to carry out this test it won't affect the result as the tester will not include it in the test, all you will be doing is making more work for yourself and demonstrating a lack of understanding of how a loop impedance test is carried out.

 

[Joshhosk]

Yes as far as I’m aware you’re correct I’ve always measured my Ze and PFC at supply side of main switch with a 3 lead High setting so Rcds should not come into effect. I take the main earth out of the earth bar and do it that way to avoid parellel paths and give true reading.

Im prepared as i can be but i hear people testing it different ways e.g. supply side of the main switch and others doing side of the load side of main switch. I do not know which way is required for my am2 which is making me nervous.

When you're testing Zs at sockets i presume you're doing 3 lead low though right?

 

[Sparks82]

The board will be locked off at all times when the board cover is off so u can only do it on the supply side
You won’t be doing zs they will all be calculated, you can do on the sockets if u want but it’s pointless and a waste of time cause you only have to write down the calculated zs for all circuits anyway and also show your calculations

 

[Joshhosk]

The board will be locked off at all times when the board cover is off so u can only do it on the supply side
You won’t be doing zs they will all be calculated, you can do on the sockets if u want but it’s pointless and a waste of time cause you only have to write down the calculated zs for all circuits anyway and also show your calculations

Okay yeah supply side is what I thought. So if it’s 3p&n
Earth fault loop impedance:
Setting on tester: L-PE and Max Z
Disconnect main earth and test between
L1-N-E
L2-N-E
L3-N-E

Re-connect main earth
Taking the highest reading and writing it in Ze

PFC
Setting on tester L-PE Max Z
L1-N-E
L2-N-E
L3-N-E

Taking the highest reading in KA and X2 to get the fault current of potential 2 phases recording it in KA ensuring it doesn’t exceed circuit breaker capacity’s

ZS
Mainswitch and 32a ring main to be turned on if safe to do so

The only live test that can be done is Zs at the sockets if a RCD is present ensure multi function tester has been set to no rcd trip to avoid nuisance tripping taking the highest Zs value which is normally the furthest socket recording it in the appropriate box

RCD
Ensuring to test both sides of the sine wave 0-180 degrees

1/2 second
1 second
5 seconds

And function test of the RCD

Functional test of all equipment once all covers have been installed back on.

Does this look right to you or can you correct me on anything?

 

[Newthy]

Hi everyone,

a few questions here

Ze: In the AM2 is it just a 2hi test between L1 - Earth, L2 - Earth and L3 - Earth. Then take the highest reading out the three? and while doing that take the PEFC reading at the same time? after reconnecting the Main earth would I record my test result on the test sheet then take the PSCC - Then which ever was highest out of the PEFC and PSCC use that for my PFC but double the answer?
Obviously when doing the Ze the board is isolated but when it comes to doing the PSCC do I re energise the board and then do the test? and do all breakers have to be on?

Also on the schedule of results there is a Zs at Db, I think I have confused myself on this. In the AM2 I'm guessing the board is simulating that it is the only board of the installation therefore will only need to do a Ze?
Is the Zs at Db for when you have another DB fed off another?

when polarity testing its just a simple voltage check between phases - do I check phase rotation while doing this as well ?
And do I have to do Phase rotation on the three phase equipment before the Zs?


many thanks

hi mate
I’m doing my am2 at the moment and genuinely these sheets have helped me

with all tests and faults explained on there as such

 

[Grant1987]

hi mate
I’m doing my am2 at the moment and genuinely these sheets have helped me

with all tests and faults explained on there as such

Those 2 pages you’ve uploaded are very good fair play clear and concise and easy to read and understand without all the nonsense. They will help many people to understand the testing requirements. I’m sure I got criticised on here for saying that the pfc test was a 3 lead test but those notes show that’s what is required.

 

[Venomx1990]

hi mate
I’m doing my am2 at the moment and genuinely these sheets have helped me

with all tests and faults explained on there as such

Hi Newthy,
any chance I could get those sheets emailed to me, trying to open the links on here but it keeps running into an error and wont load the images.

I am doing my NVQ portfolio/ trying to learn as much as possible about the am2 and testing this thread has really helped me with similar questions to OP.
Thanks
Regards
Ven