AT & AF in MCCB

[alanElec]

Recently while going through an SLD I found two ratings for MCCB with notations AT and AF.Any idea what are those notations and why they are used? What is its differnce from normal current rating provided for MCCBS??

 

[ScottyUK]

AT = Amperes, Trip
AF = Amperes, Frame

MCCBs typically come in a few frame sizes but may have many trip settings. For example a 100A MCCB is probably based on a 160A frame, and this would be denoted 100AT / 160AF