ABB NSB TF42-4.2 Relays

TF42-4.2 Thermal Overload Relay, ABB NSB series, 3-pole, part of the TF42 family. This device provides motor overload protection for 3‑phase motors in low‑voltage circuits when used with ABB NSB contactors. It features a selectable trip current range of 3.10–4.20 A and a fixed full‑load current rating of 4.20 A, making it suitable for motors with a similar FLA. Rated for 480/600 V AC systems, it supports an 18 kA short‑circuit current rating (SCCR). The unit is cataloged as 1SAZ721201R1035, with TF42-4.2 listed as an alternate catalog number. Widely available from ABB and distributors such as DigiKey and Mouser, the TF42‑4.2 integrates into NSB motor protection schemes for reliable overload protection of 3‑pole assemblies.