The ABB XT1NU3040AAA0A0XXX is a Tmax XT1 molded case circuit breaker rated 40 A continuous, 3-pole, with a 600Y/347 VAC maximum voltage and an interrupting capacity of 18 kAIC. The thermal-magnetic trip unit is fixed at 40 A, so the breaker provides both overload and short-circuit protection in one compact package. Panel-mounted with front flat terminals for straightforward bus or cable connections in a distribution panel.
Ratings and application context
The 40 A rating on the XT1N frame means this breaker is sized for feeder or branch circuits drawing up to that continuous current. The 18 kAIC at 480 VAC tells you it can safely interrupt a fault current up to 18 kA without damage — adequate for most commercial and light industrial panelboards where the available fault current is below that threshold. The 600Y/347 VAC rating confirms suitability for 480Y/277 V wye systems, common in North American lighting and distribution panels. Thermal-magnetic trip gives you a fixed thermal element for overload protection and a magnetic element for short-circuit response — no adjustment, no calibration drift over time. For a panel OEM or MRO planner, that means one less variable in the coordination study.