Rated In = 16 A with a TM220 thermal-magnetic trip unit. The overload protection (Ir) is adjustable from 11 A to 16 A, so you set the continuous current limit to match the downstream cable or load without swapping the breaker body. Short-circuit protection (Ii) is fixed at 20 x In — 320 A magnetic pickup — which means it rides out motor inrush and transformer energization but trips fast on a bolted fault. The ATFM designation indicates the trip unit is the standard thermal-magnetic type with fixed instantaneous and adjustable thermal — no electronic adjustments, no communication module. That keeps the part simple for a fixed-load line where you don't need remote trip signaling or curve shaping.
Configuration specifics
Four poles, with the neutral (N) conductor unprotected — meaning the fourth pole is a switched neutral that follows the phase poles but has no overcurrent protection. This is common in TN-S or TN-C-S systems where the neutral is bonded to ground upstream and only needs isolation, not protection. The breaker also includes a nut keeper kit, specified for a DC Power OEM in China, which locks the terminal nuts against vibration in a transport or mobile application.