Arc Fault Detection Calculator | Solar AFCI/AFDI

Arc Fault Requirements

AFCI Requirement

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NEC 690.11 Compliance

Applies to System -

Voltage Threshold -

Detection Method -

Protection Zones

DC Source Circuits -

DC Output Circuits -

String Monitoring -

System Requirements

Total AFCI Devices -

Response Time -

Annunciation Required -

Integration

Rapid Shutdown Link -

Monitoring System -

NEC 690.11 Overview


                        Required for DC circuits > 80V on buildings

                        Must detect/interrupt series and parallel arcs

                        Disable affected circuit within 2 seconds

                        Visual indication + manual restart required

                        Listed to UL 1699B

AFCI System Options

Method	Coverage	Notes
String Inverter AFCI	Per input	Most common residential
DC Optimizers	Module-level	Best fault localization
Microinverters	Module-level	Inherent low-voltage safety
External AFCI	Per string	Retrofit option

Arc Fault Types

Series Arc - Break in conductor (loose connection, damaged wire)
Parallel Arc - Conductor to conductor or ground
Ground Fault - Current to earth (separate from arc fault)