AM2 - anyone recently done it?

[pitkin2020]

Hey all, Well ive just booked my AM2 but i have to say i'm pretty nervous about now lol.

Has anyone recently done it, how did you find it?

I think my main concern is the solar element in the heating plan, as not sure what to expect there and probably the fault finding as ive not done much fault finding for a little while.

Any tips/hints much appreciated

 

[pitkin2020]

Guessing no one has recently done the AM2??

I've noticed on other am2 threads the lighting circuit has been discussed and talk about feeding the neutral through the switches. As the task is asking for PVC PVC the only way I can see you can achieve that is by using 2 x T&E as you'll need 4 cores, is that really an acceptable way or am.i over thinking it?

 

[Richard Burns]

For the AM2 you would wire as the plan states.
However there are two general methods of wiring lighting: two wire or three wire.
Either of these can be switch fed or triplate wiring as well.
The choice would be down to the installer and the layout of the switches and the lights and the wiring run between them.

If you were wiring in the two wire method when you feed the neutral through the switches you would only need a three core cable between the switches.

 

[pitkin2020]

Thanks but I'm confused a little because of your doing two way and intermediate with the ceiling rose being fed you would use 3 core between the 2way and intermediate which would be your permanent live and the 2 strappers, it would be a core short if you were required to fed the switch with the neutrals to?

 

[Richard Burns]

If you were feeding the switch and doing intermediate switching and wiring in flat PVC cable from the MCB to the switches and then to the light, it could be wired like this.
Two core from CU to 1st switch, three core between switches, two core from last switch to light.
(the red sleeving should be brown, it colour changed as I converted the image)

 

[Karin]

does this mean you get the neutral, but lose the permanent live though?

 

[pitkin2020]

ahh im with you now, thanks for that diagram that helped a lot.
Your wiring the switches in reverse as such (when feeding the light) as you dont need the permanent live to go in and out of the first switch (coming back on the switched live) just in one end and out the other lol

 

[Richard Burns]

@Karin
The permanent line only goes to the common terminal of the first switch, that line will swap back and forth between the strappers as you switch, the light fitting will only have a switched line.

 

[Richard Burns]

Just in case it may help this diagram shows the four general ways in which you can do two way switching, there are a lot of modifications that can be done moving the position of the light and the supply in various ways but this is the general principle.

For the two wire three plate wiring this can usually only be done in singles in containment as it requires a single core to each switch (though in old wiring this is what was done: a single core red cable from light to switch occasionally with an earth, just wandering under the floor!)

To do three way or intermediate lighting you really just insert an intermediate switch wired in between the L1 and L2 of each 2 way switch as I have modified the above diagram to show below.

 

[pitkin2020]

Afternoon, so i've just finished day 1 of my AM2 and could do with a little help, had a few hiccups today, but in the main i feel its going reasonably well

Basically i'm doing the practical now and have a few questions hopefully someone can help me with
1) DOL, i've wired to the DOL as per spec in singles but i cant for the life of me remember how to calculate the rating for the starter, its a 3 phase 0.37kw motor. Also coming out the DOL its being wired in SY, but there is no obvious earth point within the starter, there is a metal back plate and i did think to connect the incoming earth and the outgoing earth inside the SY using ring crimps to this, however that still leaves the SY unearthed, should i add an earth nut or banjo to the SY gland and just earth it all there and should iearth the sy sheath at both ends?

2) The FP circuit, all wired but in a quandary as the spec says to make sure you use the correct compartment within the compartmental trunking (all of them do), initially i placed it in the top compartment keeping it separate (alarm cable) but its not, as its being used as the feed for the spur so is mains, so have now moved it into the center compartment sound right.

I feel comfortable with the rest and i have 2.5 hours left to do the lighting circuit (thanks for the help earlier in the thread richard burns), finish the motor connection (just the SY part) and i have 2 more cables to wire into the heating system. Amazingly the heating system was my biggest fear and i have found that the simplest.

 

[Karin]

i missed the responses to this. just to confirm then, is there a reason for wiring the neutral to the switch (other than that it might be easiest)? i had thought it might be so one is available for future additions to the circuit but then of course at one switch you have a neutral but only a switched line

 

[pitkin2020]

yes it could be easier if your going past the switch first makes sense, less cable used passing the switch to go to a light and back again, but in the case of the AM2 its what they have spec'd

 

[Richard Burns]

Afternoon, so i've just finished day 1 of my AM2 and could do with a little help, had a few hiccups today, but in the main i feel its going reasonably well

Basically i'm doing the practical now and have a few questions hopefully someone can help me with
1) DOL, i've wired to the DOL as per spec in singles but i cant for the life of me remember how to calculate the rating for the starter, its a 3 phase 0.37kw motor. Also coming out the DOL its being wired in SY, but there is no obvious earth point within the starter, there is a metal back plate and i did think to connect the incoming earth and the outgoing earth inside the SY using ring crimps to this, however that still leaves the SY unearthed, should i add an earth nut or banjo to the SY gland and just earth it all there and should i earth the sy sheath at both ends?
If you are given the full load current set the overload to that current.
If you only have the 0.37kW rating at 400V then an approximation can be made using W/(1.732×400*pf)
pf may not be required for the AM2.

Strange there is no earth point in the starter.
The SY sheath should be earthed at at least one end of each cable.
There should be continuity across the starter for the earthing. and this should be a convenient place to earth the SY sheath.

2) The FP circuit, all wired but in a quandary as the spec says to make sure you use the correct compartment within the compartmental trunking (all of them do), initially i placed it in the top compartment keeping it separate (alarm cable) but its not, as its being used as the feed for the spur so is mains, so have now moved it into the center compartment sound right.
Fire alarm circuits should be segregated from non fire alarm circuits and FA ELV circuits should be segregated from FA LV circuits.
I would put it separately because the supply to the FA should not be disrupted because of actions on other circuits causing damage.

I feel comfortable with the rest and i have 2.5 hours left to do the lighting circuit (thanks for the help earlier in the thread richard burns no problem), finish the motor connection (just the SY part) and i have 2 more cables to wire into the heating system. Amazingly the heating system was my biggest fear and i have found that the simplest.

My ideas in red above, hopefully useful.

 

[Richard Burns]

i missed the responses to this. just to confirm then, is there a reason for wiring the neutral to the switch (other than that it might be easiest)? i had thought it might be so one is available for future additions to the circuit but then of course at one switch you have a neutral but only a switched line

Obviously convenience is a factor, but it can also permit neons, remote switches, timers, sensors and such like to be powered at the switch. However it would not be possible to continuously power something on the two wire two way wiring end switch. This method is often called conduit wiring because it is simple to do in conduit.

 

[pitkin2020]

Thanks Richard, FLC is what im going to look for to set the overload, there is a chart on the wall but too much info to take in and remember to bring here lol but im thinking as this is the AM2 the info has to be there rather than me calculating it

With the SY / Starter i may have missed the earth point so will look again, i was hoping there would be somewhere to earth the case because the sy gland would then be earthed through the casing

Im still unsure on the FP cable for the C02, its carrying 230v so is rated the same as the other cabling in the centre compartment but its also a service cable for the C02, i think my other reason for moving it to the middle is the fact it keeps the top compartment free for ELV cable which they could say i have messed up by using it, if that makes sense?

 

[pitkin2020]

Just an update, so today went in a first thin was to sort this overload out. There was a data sheet on the wall which i only glanced at yesterday, it listed the pf, efficency and the rated current for the motor at each voltage. The 0.37kw came out at a current rating of the motor as 1.1, which they listed the equation they used as wattage/(1.73 x v x pf x ef) which IIRC was 370 / (1.73 400 x 0.77 x 0.66 (66%) came out at 1.1 anyway which is what i set the overload at. The overload could be set at 0.8, 0.9,1, 1.1 and 1.2 so was pretty happy with 1.1 as the setting.

Once the practical was finished i had to dead test and complete the test sheet before doing live tests and functional testing, testing didn't go to bad until the ring where they want you to calculate and show r1+r2 /4 and r1+rn / 4, and i just went blank trying to explain it lol. Anyway all tests carried out and functional testing everything worked as it should even the heating which was a bonus.

Finished the day off with safe isolation in prep for fault finding tomorrow, consisted of isolating a single circuit (lighting), the motor circuit checking it before and after the DOL and isolating the board completely.

tomorrow will be fault finding followed by the hour long exam

 

[Richard Burns]

Sounds good so far.
I have graded the AM2 too low as I did not include efficiency in my calculation at all and even tried to remove power factor, but they were included, sorry about that but I think it sounds much better what you have done with the overload, I am glad the information was there.

It is easy to go blank at times, the ring calculation itself is easy but explaining it is not so easy.
I tend to simplify it by saying you are measuring end to end (r1,rn,r2) and then when in use, at the middle of the ring, you have each leg as half the end to end length. You also have two legs in parallel.
Length is halved so resistance is halved, because there are two (equal in some ways) legs the resistance of two identical conductors in parallel is half the individual resistance, so overall you have half and half again, so one quarter of the sum of the end to end values.
All worked and so a good result.

Good luck with fault finding, be logical and remember what test equipment you have and so the fault must be discover able with that equipment.

Then only a simple exam, can't be hard surely!!

Good luck.

 

[pitkin2020]

cheers richard youve been a great help

Thats what i tried to say with regards to the ring circuit but it sounded nothing like that lol. It was the same when i said about PFC, i said when your doing the Ze test the megger all shows it at the same time doesnt it?? I meant more that the megger shows two readings not that PFC is found when doing Ze, again knew what i meant just worded it badly lol

Hopefully fault finding wont be a major drama, can only be cable faults as they have said no faulty equipment so im expecting high resistance, reverse polarity, etc etc

 

[pitkin2020]

Well after all that I failed......so annoyed as I have failed on something so simple. I phoned the assessment centre this morning and they said it was because when testing the light I didn't test between N and E. Pretty sure I did but assessor is adamant I didn't. No point complaining rebooked to sit the 1/2 assessment again next Friday for the sum of £107.
My mark sheet below
https://goo.gl/photos/GLJ6PtW4egZHBUCc8

 

[Richard Burns]

Sorry to hear that you were denied passing.
To look on it positively you know that everything you did was good and it is not hard to train up on safe isolation!! Especially when you know it anyway.

It is possible to easily miss something and this is what the AM2 is all about, ensuring that you have the skills to catch your misses, whilst hoping that the misses are limited.

Irritating, but easily fixed and you can go in in a confident frame of mind on Friday ready to pass.
I am sure you will fly through and in later years this brief hiatus will not matter at all.

 

[pitkin2020]

Yeah as annoying as it is no point dwelling on it, I k ow the mistake and how to rectify it.
Tbh I though i had failed because I checked at the switch rather than the light as I knew the switch was the first point and had a permanent live and neutral there. I think I will do it at the light next time anyway and make sure once I've done the 3 tests I will switch one of the switches and do the 3 tests again

 

[gazdkw82]

Wouldn't testing at the switch be more accurate as it's most likely the furthest point in the circuit

 

[pitkin2020]

Wouldn't testing at the switch be more accurate as it's most likely the furthest point in the circuit

In the am2 the switch is the closest point to the DB.

I've actually passed this now and 2nd time around tested at the lumiaire. I asked about testing at the switch and they said that's perfectly acceptable also.

 

[Richard Burns]

I am glad you have passed, well done.
I think it was almost guaranteed this time and this was proved right.
Onward and upward.

 

[pitkin2020]

Yeah thanks Richard, should have been a pass the first time lol but one simple step (which I bloody well knew too) missed resulted in a fail.
Just need to finish my NVQ now which is 95% there and I'll be qualified

 

[gazdkw82]

Yeah thanks Richard, should have been a pass the first time lol but one simple step (which I bloody well knew too) missed resulted in a fail.
Just need to finish my NVQ now which is 95% there and I'll be qualified

whats left to do?

 

[pitkin2020]

whats left to do?

For me just a little bit of my NVQ, mainly the green energy section