5SY6440-7

What type of device is this?

This is a 4-pole miniature circuit breaker designed for 400 V AC systems. It is intended for protecting circuits against overload and short-circuit conditions in industrial and panel-building applications.

What is the current rating?

The rated current is 40 A. In the Siemens 5SY6440-7 configuration, this makes it suitable for circuits that require a 40 A protective device within the limits of the overall installation design.

What tripping characteristic does it use?

It has a C tripping characteristic. C-curve breakers are commonly chosen where moderate inrush currents may occur, such as in general industrial loads and control panel applications.

How many poles does it have?

It has 4 poles. This makes it suitable for use where all four conductors need to be switched and protected together in a multi-pole arrangement.

What is the rated voltage?

The device is rated for 400 V AC operation, with a rated insulation voltage of 440 V. It also has a DC rated voltage of 60 V, with a maximum DC operating voltage of 72 V.

What is the short-circuit breaking capacity?

The breaker has a 6 kA rated breaking capacity according to EN 60898, and 10 kA according to IEC 60947-2. This helps when matching the device to the fault level requirements of the installation.

Can it be mounted on a DIN rail?

Yes. It uses a quick assembly fastening method and is designed for standard modular installation, making it well suited to distribution boards and electrical enclosures that use DIN rail mounting.

How wide is the unit?

The overall width is 72 mm, and it occupies 4 modular width units. This is useful when planning panel space and component layout.

What are the main dimensions?

The breaker is approximately 90 mm high, 72 mm wide and 76 mm deep, with an installation depth of 70 mm. These dimensions can help when checking fit inside compact control cabinets or modular boards.

What cable sizes can be connected?

The terminals accept solid conductors from 0.75 mm² to 35 mm², stranded conductors from 0.75 mm² to 35 mm², and finely stranded conductors with end treatment from 0.75 mm² to 25 mm².

What terminal tightening torque is required?

The specified tightening torque for the screw terminals is 2.5 to 3.5 N·m. Applying the correct torque helps achieve a secure electrical connection.

What ingress protection does it offer?

The device is rated IP20 when conductors are connected. This indicates protection against accidental contact with fingers, but it is still intended to be installed within a suitable enclosure.

Is it suitable for industrial panel applications?

Yes. The datasheet identifies it as suitable for mechanical engineering and industrial use, making it a practical choice for control panels, machinery circuits and low-voltage distribution assemblies.

Can supplementary accessories be added?

Yes. The product data states that supplementary devices can be installed, which can be useful where the panel design requires additional functional expansion.

What standards is it designed to meet?

It is listed to IEC/EN 60898-1, IEC/EN 60947-2 and UL 1077. It also has properties for use as a main switch in accordance with EN 60204-1.

What temperature range can it operate in?

The operating ambient temperature range is -25 °C to 55 °C. For storage, the stated range is -40 °C to 75 °C.

Does it have combined terminals?

Yes. The device includes combined terminals at both the top and bottom, which can offer added flexibility during installation depending on the panel arrangement.

Is the neutral conductor switched?

No. The product data states that neutral conductor switching is not provided.