The Siemens 5SY4304-8CV is a 3-pole miniature circuit breaker with a D-trip curve and a 4 A rated current. Its 15 kA breaking capacity at 400 V AC means it can safely interrupt a fault current up to that level without welding its contacts or failing catastrophically — that's the figure that governs selectivity coordination in a distribution board. The D curve (10-20x In) is sized for loads with high inrush, like small motors or transformers, where a B or C curve would nuisance-trip on startup.
Siemens 5SY4304-8CV MCB, 15kA 400V 3P D4
MPN5SY4304-8CV
Siemens 5SY4304-8CV, MCB, Icu=15kA 400V 3P D4.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026
Product details
Frequently asked questions
What is the breaking capacity of 5SY4304-8CV?
It has a rated ultimate breaking capacity (Icu) of 15 kA at 400 V AC. That's the maximum fault current it can safely interrupt under short-circuit conditions — the number you need for panel SCCR coordination.
What does the D4 curve mean on this MCB?
The D-trip curve means the magnetic trip operates at 10 to 20 times the rated current (40 to 80 A for this 4 A unit). It's designed for loads with high inrush currents like motor starters, small transformers, or discharge lighting where a B or C curve would trip on startup.
Where can I buy 5SY4304-8CV and how is it quoted?
Sourced through independent distribution and quoted to order against an RFQ. Availability and current pricing are confirmed at quote time — no stock count or price is held open on the listing.
MPN
5SY4304-8CV