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NEC Motor Circuit Sizing Utility

The Motor Pro App is a utility application developed to assist electrical engineers and electricians with the task of connecting electric motors according the National Electrical Code (NEC).  

FLA LookUp and Breaker Sizing

This application is designed to look up the rated Full Load Amps (FLA) for Single Phase and Three Phase motors based upon Table 430.248 and Table 430.250 of the NEC respectively. Using this, the utility application then sizes the minimum breaker size needed based on a multiplier that is user adjustable in the range allowed by Table 430.52 of the NEC.  

Conductor Sizing

The utility application then sizes the minimum conductor size and conduit size, according to Article 430 and Table 310.16 of the NEC, required based on the type of conductor insulation and type of conduit specified by the user in the settings.


The equipment grounding conductor is also determined using Table 250.122 of the NEC.  

Conduit Sizing

Using the phase, neutral, and grounding conductors, the minimum sized conduit is determined using the Tables from Chapter 9 of the NEC.  

Other Functionality

Also displayed, for information purposes, is the ampacity and conduit fill of the calculated branch circuit along with calculated voltage drop for the circuit configuration for a user entered circuit length in feet.

Other Materials

Multiple insulation types and conduit types are available, with additional types to be added in the near future. 

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