You can use this free Voltage Drop Calculator to calculate the volt drop for cables by inputting your desired Load, Voltage and Cable Length and then select from the pre-set options. In some countries Voltage Drop might be referred to as Voltage Loss.
Voltage Drop Formula
The voltage drop formula is expressed as Voltage Drop = ( mV/A/m ) x L x Ib / 1000.
- mV = millivolts
- A = Amps
- L = Cable Length in meters
- Ib = Design Current in Amps
- / = Divide by 1000 to convert the result from Millivolts to Volts
mV/A/m = millvolts per Amp per Meter.
To find the mV/A/m for a type of cable, the volt drop per Amp per meter values are listed in Appendix 4 of BS 7671, however we can save you the hassle and time, as we have already programmed these values directly in to this Voltage Drop Calculator (including a correction factor for temperature).
Not only will this voltage drop calculator calculate the voltage drop in Volts, it will also calculate the voltage drop percent (%).