Service Sizing Utility

The ServiceBot App is a utility application developed to assist electrical engineers and electricians with the task of sizing electrical service entrances according to the National Electrical Code (NEC). 

Utility Transformers

This application allows the user to pick the appropriate standard sized service transformer and then calculates the typical full load amps and looks up the standard “worst case” impedance for this transformer.  

From this the app then sizes the service breaker to the next standard size breaker. The user can then adjust the full load amps, impedance, and breaker size for their specific application. 

Conductor Sizing

From this, the application is designed to look up the minimum required conductor (or parallel runs of conductors) based on Table 310.16 of the NEC.  The grounding electrode conductor is also determined using Table 250.66 of the NEC. 

Conduit Sizing

Using these conductors, the minimum sized conduit is determined using the Tables from Chapter 9 of the NEC. 

Fault Current and Voltage Drop

Also displayed, for information purposes, is the ampacity and conduit fill of the calculated branch circuit.  The app also uses the “Point to Point” method to give a worst case calculation of the available fault current at the transformer terminals. If a length is entered for the service, the app will also calculation the voltage drop and available fault current at the service entrance switchgear. 

In addition to the minimum circuit size conduit and wire shown, the user can upsize the circuit repeatedly to the next standard branh circuit size(s) to accommodate for voltage drop and/or available fault currents. 

Material Types

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

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