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Siemens 5SM1644-0FD — Residual Current Breakers (RCCB/RCBO)

Siemens 5SM1644-0FD FI-Protector, 40A 4P 0.3A 400V AC

MPN5SM1644-0FD

Siemens 5SM1644-0FD FI-Protector Type AC, 40A 4-pole, 0.3A rated residual current, 400V, 4TE width.

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

Product details

The Siemens 5SM1644-0FD is a Type AC FI-Protector (residual current device) rated 40A, 4-pole, with a rated residual operating current IΔn of 0.3A at 400V, in a 4TE (70mm) wide housing. The 0.3A IΔn is a higher threshold than the common 30mA, typically specified for feeder circuits or equipment where nuisance tripping from leakage is a concern, not for personal shock protection.

Deployment Context

The 0.3A residual threshold suits it for feeder protection where the downstream load has inherent leakage (e.g., long cable runs, industrial heaters, or motor circuits with filters) that would trip a 30mA device. It is not a personal-protection RCD — that role calls for 30mA or lower.

Frequently asked questions

What is the 5SM1644-0FD used for?

It is a Type AC residual current device (FI-Protector) rated 40A, 4-pole, with a 0.3A IΔn at 400V, used to detect sinusoidal AC earth faults in feeder circuits or equipment where a higher trip threshold is needed to avoid nuisance tripping from normal leakage.

Where can I buy the 5SM1644-0FD?

This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.

MPN
5SM1644-0FD