Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. Edelma_1

    Circuit Protective Conductor CPC calculation and Design

    I found out the fault current is calculated by first converting all parameters (fault MVA, Transformer(s), cable(s)) into their various rectangular impedances and then finding total impedance Zs and subsequent fault current for the neutral cable and CPC cable.
  2. Edelma_1

    Circuit Protective Conductor CPC calculation and Design

    I only need the K factor for Circuit Protective Conductor
  3. Edelma_1

    Circuit Protective Conductor CPC calculation and Design

    Alright thanks for the clarification
  4. Edelma_1

    Circuit Protective Conductor CPC calculation and Design

    I came across a formula for circuit protective conductors in bS76761 18th edition page 196 which states S=sqrt(12*t)/k where S is the csa (mm2) of the conductor I is the fault current t is the time in seconds for disconnection k is the factor taking account of coefficient...
  5. Edelma_1

    Harmonic Distortion Limit and Neutral Cable Sizing

    thanks Parchie, asides using instruments to find out the THD, is it possible to get it by manual calculation first before proceeding to find voltage and current values of the harmonic orders?
  6. Edelma_1

    Harmonic Distortion Limit and Neutral Cable Sizing

    I actually read the standard half way, the full standards goes thus: for multicore circuits the neutral conductor size can be smaller than the active size if the Harmonic distortion current is less than 15%. When the Harmonics are between 15% to 33% the neutral conductor size shall be same...
  7. Edelma_1

    Harmonic Distortion Limit and Neutral Cable Sizing

    Hello Everyone, I found out from IEC 60364-5-52 that for a multiphase circuit you can actually reduce the size of the neutral conductor than it`s active size if the harmonic distortion current is less than 15%. I would like to know by how many percent can one reduce the neutral.
  8. Edelma_1

    CABLE CURRENT RATINGS

    I get your point [bigsmile]
  9. Edelma_1

    CABLE CURRENT RATINGS

    you can`t neglect the service wire resistances, the service cables vary but you can use 20m of 4c x 35mm2 waveform concentric cable
  10. Edelma_1

    CABLE CURRENT RATINGS

    lol why did you make the picture blurry, the formulas are all jammed as well, kind of lumped up
  11. Edelma_1

    CABLE CURRENT RATINGS

    what software did you use for this? Take a look at this Voltage drop circuit formular
  12. Edelma_1

    CABLE CURRENT RATINGS

    @7anoter4 the 0,76 is the Voltage drop factor which is in percentage so 0,76% of 230 should be 0.0076 x 230 = 1.748 Volts 230 - 1.748 = 228 V
  13. Edelma_1

    CABLE CURRENT RATINGS

    if you are to connect 10 numbers of streetlights of say 60W 230v each along a line of 300m and you are told to give the the voltage drop at each of the lamps. Point of connection of the lamp is an LV distribution panel with a voltage drop of 0.76% and external loop impedance of 0.349 Ohms. how...
  14. Edelma_1

    CABLE CURRENT RATINGS

    Okay thanks
  15. Edelma_1

    CABLE CURRENT RATINGS

    what value does the Canadian Electric Code give for a cable of that type (3 core, XLPE 33kV, 630mm2)?
  16. Edelma_1

    CABLE CURRENT RATINGS

    my point is, why have design calculations based on seasons when winter will eventually go and summer will set in, if someone lays the cables in winter and loads it with say a sustained current ratings of 841A and summer (which has a maximum sustained rating of 756A) comes won`t it have an effect...
  17. Edelma_1

    CABLE CURRENT RATINGS

    Hello Everyone, Which of these current ratings is used as the standard current ratings for cable: Cyclic, Sustained or Distribution. For example; A 630mm2 Cu cable (dry XLPE type) has a "Winter SUSTAINED Current Rating" of 841 Amperes, a "Winter CYCLIC Current Rating" of 948 Amperes and a...
  18. Edelma_1

    Finding the Earth Fault at 11kV load side

    The TN-C is for the sheeath of the cables, they have earthings that surround the conductors. the can be aluminium or copper type.
  19. Edelma_1

    ERROR MESSAGE IN ETAP

    Thanks for the help guys, I later found out I didn`t set up some parameters which I later did and it worked
  20. Edelma_1

    Finding the Earth Fault at 11kV load side

    what if the site uses/consumes 11kV? then there would not be a need for a transformer yeah?

Part and Inventory Search

Back
Top