Panel-builder commissioning notes
The Siemens 3VA1125-4ED36-0AA0 is a SENTRON molded case circuit breaker (MCCB) in the line-protection version, carrying a rated continuous current Iu of 25 A across the full 40 °C to 50 °C band — no derating needed until you push past 55 °C, where it steps to 24 A, then 23 A at 65 °C and above. Three poles, TM210 thermal-magnetic release, and a breaking capacity that drops from 121 kA at 240 V to 76 kA at 415 V, then 53 kA at 440 V, and settles at 11.9 kA for both 500 V and 690 V — so the voltage class of your distribution bus determines which interrupting rating applies. Rated insulation voltage Ui is 800 V; maximum DC operational voltage is 500 V. The front carries IP40 protection — fine for a dry indoor panel, but not for washdown environments.
Lifecycle and sourcing reality
Mechanical endurance is rated at 20 000 operations — typical for a panelboard main or feeder breaker where cycles are infrequent but fault interruption must be reliable.
Integration dimensions and mounting
Footprint: 76.2 mm wide (3 in), 130 mm tall (5.1 in), 70 mm deep (2.8 in). Fits standard DIN-rail or direct-mount panel layouts; the 70 mm depth leaves clearance for rear-connected busbars or cable ducts in a 200 mm enclosure. Maximum power loss is 8.5 W — negligible for thermal budgeting in a ventilated panel, but worth noting if the breaker is packed tightly alongside other heat sources.
Fault isolation and field service
The TM210 overcurrent release is a fixed thermal-magnetic type — no interchangeable trip units, so the 25 A rating is baked in. For a field swap, verify the load current hasn't drifted above 25 A continuous; the breaker holds 25 A through 50 °C ambient, then derates. Operating temperature range spans -40 °C to 70 °C; storage extends to 80 °C maximum. The -40 °C floor matters for cold-start installations in unheated shelters or outdoor enclosures.