Investigation on Branch/Feeder Arc Fault Circuit Interrupter Incorporating Equipment Ground Fault Protection

 

At the present time the UL Standard for Arc-Fault Circuit-Interrupters (AFCIs) does not require AFCIs to detect a high-impedance fault condition known as a "glowing connection". Paragraph 1.3 of UL 1699 states:

 

These devices are not intended to detect glowing connections.

 

The glowing connection has been documented by a number of technical investigators as a potential ignition mechanism. The purpose of this investigation was to assess the ability of a Branch/Feeder AFCI incorporating ground fault protection to respond to a glowing connection occurring at a wiring device termination. The ability to interrupt such a thermal event is seen as an additional mechanism by which AFCIs may be used to reduce the risk of electrical ignition.

 

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