Derating and thermal reality
The 3 A rating holds at 35 °C. At 40 °C it drops to 2.86 A, at 50 °C to 2.71 A, at 60 °C to 2.54 A.
Mounting and fit
IP20 with conductors connected, so it's fine inside a closed panel but not for wet locations.
Siemens 5SY7403-7 SENTRON MCB, 4P C-Curve 3A, 15kA/40kA
MPN5SY7403-7
Active
Siemens SENTRON 5SY7403-7, 4-pole miniature circuit breaker, C-curve, 3 A rated, 15 kA (EN 60898) / 40 kA (IEC 60947-2), 4 MW.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026
Specifications
| Parameter | Value |
|---|---|
| Brand name | SENTRON |
| Application suitability | Mechanical engineering / industry |
| Parameter | Value |
|---|---|
| Number of poles | 4 |
| Pole configuration | 4P |
| Rated current (In), AC | 3 A |
| Rated voltage, AC (multi-phase) | 440 V |
| Rated voltage, AC (single-phase) | 440 V |
| Voltage type | AC |
| Parameter | Value |
|---|---|
| Tripping characteristic (trip curve) | C |
| Rated breaking capacity (Icn), per EN 60898 | 15 kA |
| Rated breaking capacity, per IEC 60947-2 | 40 kA |
| Breaking capacity, AC (UL 1077 / CSA C22.2 No.235) | 5 kA |
| Energy limitation class | 3 |
| Overvoltage category | III |
| Pollution degree | 3 |
| Degree of protection (IP) | IP20, with connected conductors |
| Neutral conductor switching | No |
| Touch protection | Yes |
| Parameter | Value |
|---|---|
| Width in modular units | 4 |
| Width | 72 mm |
| Height | 90 mm |
| Depth | 76 mm |
| Installation depth | 70 mm |
| Fastening / mounting method | Quick assembly system |
| Mounting position | any |
| Combined terminal, top | Yes |
| Combined terminal, bottom | Yes |
| Tightening torque, max. | 75 °C |
| Tightening torque, min. | -40 °C |
| Sealable | Yes |
| Parameter | Value |
|---|---|
| Halogen-free | Yes |
| Silicone-free | Yes |
| Influence of ambient temperature (derating) | max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C |
Product details
Frequently asked questions
How do I get current pricing and availability for 5SY7403-7?
Submit an RFQ through this listing. Availability and current pricing are confirmed at quote time through independent distribution channels.
What is 5SY7403-7's listed depth and width?
Depth is 76 mm overall; width is 72 mm (4 modular width units). Installation depth is 70 mm.
What compliance documentation does Siemens provide for 5SY7403-7?
The breaker is halogen-free and silicon-free, rated for pollution degree 3 and overvoltage category III per IEC 60947-2 and EN 60898. Touch protection is built in.
MPN
5SY7403-7