Voltage Drop Details

British Standard 7671. Again.

Is the British Standard 767 similar to the US NEC? Does it dictate a max VD?

Cable does not have an allowable % VD. You must determine what is the max VD you can tolerate. The NEC Std suggests 3% but not mandatory. It is a design problem.

The allowable voltage drop depends upon how the electrical power distribution system has been designed and the capability of the electrical loads to function suitably at the reduced voltage at the terminals of the electrical equipment. In case of motor loads you also need to take into account the voltage drop occuring diuring the starting time. Voltage drop for sizing of cables is mostly applicable for voltages upto 1000V. As a general rule for volatge levels of 3.3kV, 5kV, 6.5kV and higher it is the fault current carrying capability that plays a major role.

The standards refered by you do not define a certain % voltage drop for a cable.

How long is a piece of string?

Dear sir,

It is approximately 500mts

Thank you.

Regarda,

T.Kailash Kumar