For a load drawing 800 amps, what is the minimum gauge required for conductors in each conduit when using three parallel conduits?

To determine the minimum gauge required for conductors in each conduit when using three parallel conduits for a load drawing 800 amps, it's essential to understand how parallel conductors share the current and how conductor sizing is governed by the National Electrical Code (NEC).

When conductors are run in parallel, the total current is divided among the conductors. In this case, with three parallel conduits, each conductor will carry one-third of the total current. This means that each conductor would need to handle approximately 267 amps (800 amps divided by 3).

Referring to NEC guidelines, the ampacity of conductors is critical for ensuring safety and efficiency. For copper conductors, the ampacity must be sufficient for the expected load while also considering factors like temperature ratings, installation conditions, and conduit fill.

In this scenario, a 300 kcmil conductor is typically rated to handle around 280 amps, which is suitable for the 267 amps that each conductor will handle in parallel. Therefore, using 300 kcmil conductors means that they can safely handle the load without exceeding their ampacity limit, thus ensuring compliance with electrical safety standards.

Choosing a larger gauge, such as 400 kcmil, could be unnecessarily