What is the maximum recommended voltage drop for branch circuits according to the National Electrical Code (NEC)?

The maximum recommended voltage drop for branch circuits according to the National Electrical Code (NEC) is typically set at 3%. This guideline exists to ensure that the electrical system operates efficiently and that electric vehicles (EVs) and other connected devices receive adequate voltage for optimal performance.

A voltage drop exceeding this limit can lead to inadequate power delivery, which may cause electrical devices to function improperly or even sustain damage over time due to insufficient voltage. In the context of electric vehicle charging, maintaining the voltage drop within this recommended limit is especially critical since EV chargers often require significant power to operate efficiently, particularly during fast charging.

Using this 3% threshold helps to minimize energy losses in the wiring and ensures that the system adheres to safety and performance standards outlined by the NEC. Maintaining the recommended voltage drop is part of good design practices and is essential in ensuring the reliability and longevity of the electrical installation in EV charging systems.