40 A MCCB with TM240 release — line protection duty
The TM designation means it uses a fixed thermal element for overload protection and a magnetic trip for short-circuit events — no interchangeable trip units, so the 40 A rating is locked at order time. At 240 V it interrupts up to 187 kA, which covers most utility-transformer-fed services in North America; at 415 V the breaking capacity drops to 121 kA, still sufficient for most European distribution panels. The 4-pole configuration (three phases plus neutral) makes it suitable for three-phase four-wire systems where the neutral needs overcurrent protection.
Above that it begins to taper: 39 A at 55 °C and 60 °C, 38 A at 65 °C, and 37 A at 70 °C. The width is a standard 4-inch (101.6 mm) module, which fits a typical DIN-rail or panel-mount cutout for a 4-pole MCCB.
The interrupting rating drops steeply as voltage rises: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. For a 480 V panel in North America the relevant figure is the 440 V column (75.6 kA) since 480 V is close enough that the 440 V rating governs in practice. At 690 V the 17 kA limit means this breaker is not a high-fault device for 690 V industrial systems — coordinate with upstream fuses or a higher-rated frame if available fault current exceeds that.