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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.

I only need the K factor for Circuit Protective Conductor

Alright thanks for the clarification

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...

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?

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...

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.

I get your point [bigsmile]

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

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

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

@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

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...

Okay thanks

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

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...

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...

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

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

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