Let’s face it; you’ve probably never heard of the term Voltage Drop, and if you have, it isn’t something that crosses your mind every day. However, making it a consideration every so often could be beneficial to the life of your operating equipment. Misconceptions are common when it comes to voltage drop, but learning why it’s important and how to calculate it could end up saving you time, money and heartache in the long run.
The term “voltage drop" essentially refers to the reduction of voltage in any electrical circuit. It is the electrical potential of the circuit lessening across a component or conductor. A significant drop in voltage could be the negative result of an incorrect conductor size in a cable.
When in the process of choosing a cable for a specific circuit, a common standard used to determine the cable type and size often is ampacity. Ampacity refers to the greatest current a conductor can carry. In some situations, opting for a larger conductor size than required is essential. Usually these instances occur with long runs of electrical wire when, because of the excessive voltage drop, a larger conductor size is necessary to carry the existing current. Voltage drop thus becomes a major concern when installing long lengths of wire.
In long runs, the total voltage lost between the power supply and the device being powered can be considerable. In short circuits, voltage drop will not be a major consideration because the total voltage lost is not substantial. For example, with residential buildings wired circuits are typically not long enough for voltage drop to be a factor of consequence.
Some people are under the impression that the NEC (National Electric Code) requires you to size conductors to accommodate voltage drop. Although the NEC recommends that the maximum on branch circuit should not exceed 3%, this is only a recommendation and is not mandatory. Having a voltage drop higher than 3% is not necessarily a safety concern, but rather a performance concern.
In the appropriate circumstances, finding out voltage drop is a wise first step because low voltage has many negative consequences, such as wasted energy in the wiring system. Wasted power is commonly followed by poor operation of electrical equipment, among other problems. Determining voltage drop is essential, since not doing so could be detrimental to the life of your equipment.
Contact Allied Wire & Cable (AWC) for more information.
Disclaimer: All information on this site is provided for informational purposes only! By no means is any
information presented herein intended to substitute for the advice provided to you by any health care or other professional
or organization.
