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.
Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026
Specifications
| Parameter | Value |
|---|---|
| Overvoltage category | III |
| Parameter | Value |
|---|---|
| Width | 72 mm |
| Height | 90 mm |
| Depth | 76 mm |
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