The Siemens SENTRON 3VA2040-5HM36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 40 A continuous current, with an adjustable thermal-magnetic trip unit covering 60 A to 480 A. That adjustable range means one breaker body covers multiple feeder sizes — you set the trip threshold to match the downstream load, not the other way around. The 187 kA interrupting rating at 240 V is the headline number, but the real-world fit depends on the available fault current at your service voltage: it holds 121 kA at 415 V and 440 V, drops to 75.6 kA at 500 V, and to 3 kA at 690 V. If your system runs at 480 V or below, this breaker handles most industrial fault levels without upstream fusing. At 690 V it's essentially a load-break switch — plan accordingly.
Thermal performance — no derating headache
No derating curve to calculate for warm enclosures, no summer-time nuisance trips. That's unusual for a thermal-magnetic breaker and simplifies panel design for hot environments like pump houses or enclosed switchgear.