Transformer, Neutral Earthing

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    Lets supose that we have 6 cables (240mm2)  per phase bettwen da transformer and the main circuit braker in the electrical cabinet and also 6 cables per phase on the neutral, assuming that is a 4 pole circuit breaker, the 6 lines from neutral also go to the circuit breaker, and then to the busbars in the Cabinet. My question is about the conection bettwen the neutral of the transformer and the ground, ou many lines and with cross section ?, that line(s) goes to a bar and then from the bar to the ground for example a naked wire of 35 mm2 ?


    Thank you ?


    It is necessary to create an outlet connects realizezei soil and ground terminal of the transformer and plug the newly created. In my country may be about to strip OlZn with minimum 100 mm square section.


    the location of the earthing point is based on the earthing system your applying to your network  (TN-C,TN-S, ,TT & IT)


     In this system the neutral and protective conductor are combined , the conductor is connected between the transformer star point and the equipment neutral /earth point . additional earthing point (rods) is not required on the equipment side 


    in this system the earthing and nutral  conductors between transformer and equipment are not combined ( separated ), they have to be connected back to the transformer star point, additional earthing point (rods)  is not  required on the equipment side 


    in this system the only nutral  conductors between transformer and equipment is connecetd  , the exposed conductive part of the equipment shall be connected to local earth point by means of protective conductor. 


    its the same as TT system except the the source neutral point is connected directly to earth ,its connected through low impedance earth electrode (earthing impedance)


    there is also other compination such as TN-C-S


    the protective cable size selection is based on BS ≤7671

    1. for phase conductor size  S≤ 16mm2 the protective conductor size shall be equal to the phase conductor size
    2. for phase conductor size between 16<S≤35mm2 the protective conductor size shall be 16mm2
    3. for phase conductor size  S>35mm2 the protective conductor shall be 1/2 phase conductor size 





    Thank You.


    hi every one

    imeed using and consttruction of auto transformer

    and the method of cooling of power transformer

    and the needs of cooling. last thig the information about

    the PCBs


    thank u


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