BOM / RFQ

Siemens 5SY4340-7CV — Miniature Circuit Breakers (MCB)

Siemens 5SY4340-7CV MCB, 3P C40, 15kA Icu at 400V

MPN5SY4340-7CV

Siemens 5SY4340-7CV, miniature circuit breaker (MCB), 3-pole, C-curve, 40 A rated current, 15 kA interrupting capacity at 400 V AC.

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Siemens 5SY4340-7CV datasheet (PDF)

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Product details

What the 15 kA Icu rating means for panel coordination

Provided the upstream transformer and cable impedances keep the fault level under that 15 kA figure, this breaker holds selectivity with a suitably rated upstream device — no cascading failure into the bus.

Snap-on DIN rail mounting per EN 60715. The 3-pole footprint occupies three modular widths (17.5 mm per pole). Terminals accept copper conductors up to 25 mm², which is adequate for the 40 A rating on a 400 V three-phase circuit feeding a distribution sub-board or a motor control centre feeder.

Frequently asked questions

What is the breaking capacity of the 5SY4340-7CV?

The 5SY4340-7CV has an interrupting capacity of 15 kA at 400 V AC, as indicated by the Icu rating in the description.

Where can I buy the 5SY4340-7CV?

This part is sourced to order against an RFQ through independent distribution channels. Contact us with your quantity and target price; availability and current pricing are confirmed at quote time.

What is the 5SY4340-7CV used for?

It is a 3-pole C-curve 40 A miniature circuit breaker rated for 400 V AC systems, used for cable and equipment protection in distribution boards, sub-distribution panels, and motor control centre feeders where the prospective fault current does not exceed 15 kA.