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  1. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Morning all, Matthew here

    Have my pre AM2 this week and then the real deal starts Monday! So I signed up to look at any previous posts about the AM2 ( Pobably a few on here id imagine)
     
  2. Dan
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    Dan I'm not a sparky but I know a couple ;-) Staff Member

    Location:
    Staffordshire
    Welcome aboard Matthew, site:electriciansforums.co.uk AM2 - Google Search - https://www.google.co.uk/search?q=site%3Aelectriciansforums.co.uk+AM2&oq=site%3Aelectriciansforums.co.uk+AM2&aqs=chrome..69i57j69i58.6973j0j7&sourceid=chrome&ie=UTF-8 - Some searches from Google. Change that to "AM2 Assessment" to find assessment related threads and posts. You can add the year to the search too if you want just the more recent threads and posts. :)

    If you have any specific questions, post in the main electrical forum and I'm sure some of the lads will be able to help a bit.
     
  3. Richard Burns
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    Richard Burns Trusted Advisor

    Location:
    Cambridgeshire
    Business Name:
    Richard Burns
    Welcome to the forum.
    A fair number of posts on here about AM2, have a look at similar posts, just below these this thread, but do watch the dates.
     
    • Like Like x 1
  4. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Best tip I can give you for the AM2: Write everything on the back of your schedule of test results. R1+R2 at each point, Zs at each point, RCD values x1 and x5, FPC / FSC, 3 phase double PSC value, the more the better.

    Ring Circuits:

    Use the formulas to calculate expected R1+R2, Ring Continuity for the neutral / earth and Zs

    Expected R1+R2: r1+rn /4
    Expected Zs = Ze + (r1+r2)
    Expected Ring continuity for Neutral: r1 = r2
    Expected Ring continuity for Earth: r2 = r1 * 1.67 NOTE: Assuming you are wiring your Ring circuit in 2.5mm If not take the line and divide it by the earth. Example: 2.5/1.5 = 1.67

    Cross link your ring final circuit and test each socket for the same reading or a reading within 0.05 Ohms.
    Anything higher than this is typically a spur from another socket but not always.
    Sometimes it's worth plugging your tester in and out a few times to clear the muck off the brass in the sockets.

    Mark the outgoing and incoming ring cables in the distribution board for ease of testing later on.


    Testing:

    DONT FORGET TO NULL YOUR TEST LEADS AS IT LEADS TO FALSE VALUES

    DO THE TESTS IN THE CORRECT ORDER:
    RING CONTINUITY, CPC, IR, Zs, RCD, Polarity, RCD Test Button

    IR test should be done at double the working voltage. 500V up to 500V with the exception of SELV / PELV (250V)

    Make sure nothing is plugged in and any neon indicators / lamps are removed from the circuit. Switch all light switches to ensure all the cables are IR tested. A lot of people forget to do this with 2-way lighting circuits. Personally, I like to test at 230V first to make sure I get a good reading before pumping 500V down the circuit and blowing up someone's appliance.


    Ensure the RCD Tester is set to the correct mA for the RCD /RCBO, 30mA usually (Could be different for you)

    Safe Isolation

    10 TESTS FOR 3 PHASE

    L1 - E
    L2 - E
    L3 - E

    L1 - N
    L2 - N
    L3 - N

    L1-L2
    L2-L3
    L1-L3

    N-E

    3 FOR SINGLE PHASE

    L-N
    L-E
    N-E

    Make sure you select the GS38 compliant tester and proving unit and follow the safe isolation procedure step by step.


    I could keep going but I would be here all night, maybe I will get around to making A tips and tricks guide some time ;)


    Honestly a lot of the things I am telling you, you will be told on your pre AM2 but you need to ensure you do them on the day of your exam.

    Good Luck!
     
    • Like Like x 2
  5. LeeH
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    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    Practice your pyro and steel conduit bends?
     
  6. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    The AM2 has changed a lot from how it used to be, now you just install cables as opposed to fabricating the installation
     
  7. LeeH
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    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    Easy peasy then!
     
  8. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    Thanks all much appreciated! Two days of pre am2 complete, alot to take in regardless of containment taken out, everything has to be wired as they spec and tested how they want it! Like a global IR test with the ring disconnected (earths still connected neutral and live blocked separate) then tested againt the the outgoing side of the main switch ( L-N L-E N-E of the ring, then L- L1 L-L2 L-L3 N-L1 N-L2 N-L3) thats new to me! And i cant remember if we had to disconnect the lighting feed or just switch it off via the mcb during the global IR! Also a lot of formulas thats need to be wrote down on scrap notes otherwise you will fail. Eg motor overload convert Kw into W then divide by 3 ÷ 230 x 1.1. Load of nonsense but there we are. To say my head hurts would be puttint it lightly!
     
  9. LeeH
    Offline

    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    You lost me on the motor. You set the OL to the nameplate FLC. Simples.
     
  10. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    What you mean?

    Thats the equation we were given today...
     
  11. LeeH
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    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    So,

    3kW = 3000W

    3/230x1.1=0.01

    3000/0.01=300000

    WTF?
     
  12. Leesparkykent
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    Leesparkykent You Rock Gmes Staff Member Trusted Advisor

    Location:
    Kent
    The way he's written it

    3KW=3000W

    3000W/3=1000

    1000/230=4.34A

    4.34Ax1.1=4.78A

    ...........I don't get it either
     
  13. LeeH
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    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    That's the way my little brain saw it. I still have no idea.
     
    • Like Like x 1
  14. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Thats the equation we have in our notes ..

    Convert into W eg

    3kw - (3000w ÷ 3 ÷ 230 x 1.1).......

    No?
     
  15. Sintra
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    Sintra The Innkeeper Staff Member

    Location:
    Belfast/London
  16. LeeH
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    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    I must be missing a trick here Matt.

    The reason why you take the nameplate figure to set your overload is because the kW rating is the shaft output not the electrical load.

    You need to use powerfactor and efficiency in the equation don't you?

    A 3 phase motor is around 6 amps IIRC, a single phase will be more.

    So the 4.78A makes no sense to me.

    Did the tutor not explain why?
     
  17. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare

    Nope, no explanation just a sum which was ÷3 ÷230 x1.1... they dont really explain stuff he just said ' make sure you note the equation down on the paper provided' if they explained everything the 2 days wouldn't be enough in dont think!
     
  18. Wilko
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    Wilko Electrician's Arms

    Location:
    Berkshire
    Business Name:
    Wilko Electrics
    Hi Matthew - can I ask where you did your prep, and any thoughts? Thanks
     
  19. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Hello, the formula I was given for setting a motor overload is as follows:

    (Motor current / 1.73) + 30%

    So take the Motor rating; in Your case its 3kW


    using I = P / V
    I = 3000W / 400V = 7.5A

    Now you divide the motor current by 1.73 (Square root of 3) to get the current per phase.

    7.5A / 1.73 = 4.34A

    Take 30% of the above and add it to the existing value for max operating current to be achieved without the overload tripping.

    4.34A * 1.3 =5.64A

    You would set your overload to 5.64A





    The way the formula you have been given is as follows:

    The Value of motor is 3Kw, Convert this into watts.

    3kW = 3000W

    Now divide the value by 3 as there are 3 phases giving you 1kW per phase

    3000W / 3 =1000W

    Divide the 1000W by the voltage to give you the current per phase

    1000W /230V = 4.35A

    Now Multiply the current given by 10% to allow for max operating current to be achieved without the overload tripping.

    4.35A x 1.1 = 4.79A



    The difference between the 2 is: My formula applies A 30% Addition, Yours applies a 10% Addition.


    Hope that Helps you understand it a little better.
     
  20. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    So if my motor is 4.5kw

    I have 4500 ÷ 3 ( for each phase) = 1500

    1500 ÷ 230 ( should this not be 400 if its three phase) = 6.52

    6.52 x 1.1 ( for 10% overload ) = 7.15a?

    Im getting confused as why is it ÷230 if its a three phase motor? Or is it becsuse each phase is 230?

    Thanks for your help though.
     
  21. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    If your motor is 4.5kW using your method you would do the following:

    4.5kW in Watts = 4500W

    4500W / 3 = 1500W (This is where you divide the power of the motor by 3 for the 3 phases)

    1500W / 230V = 6.52A (This gives you the current per phase)

    6.52A * 1.1 = 7.15A (This applies the 10% for max operating current to flow without overload)
     
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  22. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Appreciate that mate, thank you very much!!
     
  23. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    No Problem, if you need help with anything else, just ask.

    Good Luck Tomorrow!!!
     
  24. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Im pretty good with everything else, safe isolation and risk assesment im okay. Install okay as far as im concerned only the s plan heating I think will throw me off as i know I will over complicate it!! Testing im quietly confident and fault finding will be me hoping for 7 faults on the data.... lol!

    Cheers though, ill let you know! :)
     
  25. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Study this:

    [​IMG]

    Simplified S-Plan Wiring Diagram
     
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  26. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    Surely it cant be as easy as taking a single cable from room stat terminal 2 to the main wiring centre terminal 5?
     
  27. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    You would run 3 core + cpc from the roomstat back to the wiring center. Sleeving all cables appropriately. My drawing just shows how it needs to be connected.
     
  28. Leesparkykent
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    Leesparkykent You Rock Gmes Staff Member Trusted Advisor

    Location:
    Kent
    Just remember the order it switches. programmer to thermostat, thermostat to valve, valve to boiler and pump.
     
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  29. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Oh yes, my bad! But surely some will require just a single core no? The orange for instance?
     
  30. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    No , The Valve comes with a 5 core cable pre-attached.

    Grey = Perm Live
    Blue = Neutral
    Green / Yellow = Earth
    Orange = Boiler call (SW)
    White / Brown = Valve Call (Just noticed on my diagram I didn't label the brown from the valve as white as both colors can be used depending on the manufacturer)

    I will update that now
     
    Last edited: Nov 20, 2016
  31. Leesparkykent
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    Leesparkykent You Rock Gmes Staff Member Trusted Advisor

    Location:
    Kent
    The oranges are part of the valve flex. Each valve flex will have grey, brown, blue, orange and green/yellow.
     
  32. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Just remembered another TIP for you, Ensure you use heat resistant flex not standard flex.
     
  33. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
  34. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    P
    Was okay as far as im aware... got 2 hours 40 left to finish off the heating system! A lot easier than i first thought it would be! For some odd reason i used 6mm gutter bolts for the fp clips not m4s lol!!! Will have time to change that tomorrow though! Also used one for tha banjo on the main DB but as I was putting stuff away I seen brass hex heds so ill swop them around tomorrow :) testing tomorrow afternoon now!
     
  35. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Did you have to fit SY cable?
     
  36. Matthew terry
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    Matthew terry Active EF Member

    Location:
    Aberdare
    Yep?
     
  37. Jamchiv01
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    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    • Like Like x 1
  38. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare

    It was a 4 core sy!

    The earth into the block and also flew an earth off the piranha lock nut to the same block too!

    By sleeving the strands what exactly do you mean? But picture one is the one we were shown to do.
     
  39. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Sorry was eating dinner.

    I only have 3 core SY with me hahaha.

    [​IMG]

    Bonus marks for using the piranha nut on the SY :) I only used those on the SWA
     
  40. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    Dont worry :)

    No we weren't told to sleeve! Just to wrap it around clockwise and clamp together. Yeah its not on the spec to come off the sy onto the fake motor housing but theres no way to earth the backbox so i came off the piranha and into the earth from the sy!
     
  41. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    There should be a bolt for your crimp to connect on to on the backbox. At least there was when I did my AM2.


    ALSO Just remembered something else, Your ring final circuits, how have you done your earth connections?

    If you look on the back of the socket they specifically have 2 earth terminals, 1 for one earth in and one for out.

    Usually, you do this for computer circuits but they specified we needed to do it in the exam.
     
  42. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    Nope, nothing on there its only like a metal back box with a front cover which has a photo of a motor! Lol also the socket we are using only have one earth terminal in the back so i shouldnt have that problem really :)
     
  43. LeeH
    Offline

    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    I doubt the SY braid should be Green/Yellow.
     
  44. Matthew terry
    Offline

    Matthew terry Active EF Member

    Location:
    Aberdare
    Hope not anyway! Lol!

    Well my rig worked and everything tested out ok ( as far as in know) just fault finding and online exam!
     
  45. Jamchiv01
    Offline

    Jamchiv01 Electrical Installer

    Location:
    Swindon, Wiltshire
    Inside my pre AM2 pack, we were told to use the braid for an earth of the extraneous conductive part, namely the braid. The braid must not be used as a CPC. The picture below the text shows the braid sleeved green / yellow connected to the backbox.

    @LeeH@LeeH What would you sleeve the braid? Or would you leave it?
     

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