Cable length calculation

[Brucky]

Hi people,
I'm carrying out an online course to gain my qld electrical licence.
Been a good while since calculating cable length using equations and regs books.
Can anyone guide me to the correct equations please
Thanks in advance

 

[telectrix]

what exactly do you want to calculate? if it's max. length of a circuit, use the mOhms/m to determine the resistance (R1+R2) for the length you envisage, or conversely, to determine the max. cable length to give an acceptable Zs. then the mV/A/m to ensure that volt drop is within limits.