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  1. W

    Calculating power consumption

    I have a 415, 55kw motor running at 30 amps for the best part of 12 hours a day. If i am to calculate the power consumption, what equations would i use; if i use P = 1.73 x 418 (measured) x 30 xPF x efficiency what values would i use for efficiency and PF, i thought these values change...
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    Earthing conductors

    If a TNS installation has 16mm tails, and a 10mm main earthing conductor, would 6mm main equipotential conductors be ok to use (ie to gas, water etc) or would you have to use 10mm as that is what the main earth is?? Thanks
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    RCD Tripping instantly

    will do so tomorrow and keep you all posted!!! thank you for your help
  4. W

    RCD Tripping instantly

    sorry, wasnt being sarcastic, genuinely didnt know if a trapped neutral would cause other circuits! i have changed a socket face today as well as finish the cookerpoint so a possibilty.
  5. W

    RCD Tripping instantly

    both fridge and cooker are out of the box brand new! would a trapped N- E on one circuit affect others on it??
  6. W

    RCD Tripping instantly

    re: registered. not part p but have done the 2391 and bs7671 so like to think i know what im doing! just not seen a fault like this before. The IR readings for both circuits were ok when the work was first carried out. All earths are sleeved. Yes it is TNCS, Reading was 0.44 ohms...
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    RCD Tripping instantly

    thanks for the quick reply. It is on the RCD side because of the socket which is on the coooker connection unit and if i plug the cd player into it it works fine so i dont think ive got the neutrals mixed up at the board?? Good point about the earth not being connected, must admit didnt...
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    RCD Tripping instantly

    Guys Just witnessed something weird and was wondering could you help. Recently replaced a CU in my brothers house that he is renovating. I undertook the rcd tests using an alphatec tester and it tripped in the required times (and not at 1/2) so i was happy that all was ok..... until today...
  9. W

    garge wiring

    the gap between the garage and the house is less than 1 metre with the total run not exceeding 5m. I am planing to use 4mm cable (pvc) with conduit running between the two buildings. The mcb is an old type 16a (push button type). Inside the garage is a new rcd unit with a 16a and a 6a mcb...
  10. W

    outside power

    friend of mine want lighting in his decking. i was going to run a cable from the cu through to the garage and install a smaller cu for the outside power etc. due to the way the joists are this is impossible without lifting the boards which is not an option. Would you recommend spurring off...
  11. W

    Inspection and test

    it has been some years since i took the 2391 exam and i was asked by a friend yesterday to 'see if i need a rewire'. I undertook all the relevant tests, all the cables were new ish but all identified correctly etc. He asked me if he needed a new board as the one he had used fuses, but was...
  12. W

    What can be wrong?!!

    Hi, I have recently moved into a house that has just been built and im having problems with the central heating system. The tap pumps out water that is too hot to touch eventhough the thermostat is set at 45 degrees! Secondly, the water is constantly on even though the control panel clearly...
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    TT earth rod resistance

    Any ideas how to test the value of the earth rod resistance, as of yet I do not have the 4 lead meter tht is required. Is there another way?? Was under the impression that if the whole house is under RCD protection (100ma time delay and 30ma split) there would no need to calculate this. Please...
  14. W

    Identifying installation type tt??

    intersting, didnt know they would do that? how do i go about asking that question??
  15. W

    Identifying installation type tt??

    Hey guys, looking at a friends house installation that he wants checked out before he has a rewire. Looking at the main supply cable to the house (old terraced house) there are only 2 conductors in the PVC cable (16mm red and black). Looking further there appears to be no earth bonding to pipes...
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    12v between earth and live when switch is off

    Hey fellas, waas wondering if you could help me trace a problem. When i switch off the downstairs socket in a house i have been asked to check, there is 12v between the live and earth pin of the double socket. The swicth is a chrome double pole and all cables are terminated correctlly...
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    Installation test equipment

    I am thinking of buying a new tester, the Alphatek Easitest, has anyone used it and have they any comments to make about it?? Thanks
  18. W

    Backplate

    Does anyone know where i can purchase back plates for after market light fittings?? Thanks
  19. W

    Dangerous installation

    absolutely, i totally agree with you. will someone please also enlighten me as to when it is not a requirement to connect a main earth as one of the previous posts suggest. i am absolutely baffled
  20. W

    Dangerous installation

    no he did not issue a certificate, turns out he is a friend of a friend doing it 'cheaper'.
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