Electricity can be described using the example of a water hose. The water supply pressure is the voltage, or the amount of force that is capable of pushing the water through the hose. The hose is a conductor, which is a pathway for the water to travel to a certain destination. The flow of water through the hose is the current. The amount of water that comes out of the hose is power. When talking about electricity, we replace the water in the example with charged particles.

The conductors used in the above example are made of materials with a low resistance. Resistance is the measure of how well a material will allow electricity to flow through it. All materials have some form of resistance. The materials with a very high resistance are called insulators. The materials with a low resistance are called conductors. In the USA, conductors are typically composed of copper or aluminum.

Voltage drop is the concept of how much voltage is reduced when power is flowing from the source to the destination. Low resistance materials have low resistances, but those resistances grow as the length of conductors continue to grow. Hence, it is possible to have a 100 volts at the beginning of the conductor and only 90 volts available at the end of a conductor when the electricity is flowing. Voltage drop is typically expressed as a percentage. In the above example, a 10 volt drop from 100 volts would be described as 10% voltage drop.

Building codes address tolerances for allowable voltage drop. If the voltage drop is outside of those tolerances, there are different methods to correct the situation. One method of correcting for voltage drop is to provide a larger conductor. Larger conductors have less resistance than their smaller counterparts. A second option is to add additional conductors to minimize resistances. Running additional conductors in parallel reduce the resistance encountered by the source. A third option involves adding transformers to the circuit. A transformers is a combination of magnets and wires used to adjust the voltage. Corrective actions will likely have different financial impacts, as well as other considerations.

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