A 15-amp circuit operating at 120 volts has a maximum theoretical capacity of 1,800 watts. This calculated wattage serves as the absolute ceiling for the circuit's power consumption. Voltage: What's the Difference? It's important to distinguish between amps and voltage. In the. In this guide, we'll break down the 12 main types of distribution boxes in a way that's easy to understand. We'll chat about what each one does, where it shines, and then dive into how to choose the perfect box for your needs. Plus, we'll sprinkle in some practical tips to make sure you're not. A distribution box, also known as a power distribution box or electrical distribution box, is used to distribute electrical power safely to multiple circuits.