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5SY4120-6
Siemens 5SY4120-6 available at EU Automation. Get in touch today for a quick price.
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What happens next?
1. Email confirmation
You will get an email confirming that we have received your enquiry.
2. Dedicated Account Manager
One of our team will be in touch to confirm your part(s) specification and condition.
3. Your quote
You will receive a comprehensive quote tailored to your specific needs.
Siemens 5SY4120-6 (also referenced as 5SY41206) is a SENTRON 5SY4 miniature circuit breaker designed for reliable overcurrent protection in low-voltage distribution and control panels. This 1-pole device features a B tripping characteristic and a 20 A rated current, making it well suited to circuits where predictable protection against overloads and short-circuits is required.
Rated for 230/400 V AC with a 50/60 Hz supply frequency range, the 5SY4120-6 offers a 10 kA short-circuit breaking capacity to EN 60898-1, with additional performance ratings in accordance with IEC 60947-2. The compact, single-module (18 mm) format mounts via a quick assembly system on standard DIN rail and supports flexible installation orientation. Combined terminals top and bottom simplify panel wiring, accommodating solid or stranded conductors from 0.75 to 35 mm² (and finely stranded with end processing up to 25 mm²), with a recommended tightening torque of 2.5 to 3.5 N·m.
Built for demanding industrial environments, it is halogen-free, sealable and silicon-free, with IP20 protection (with connected conductors), energy limiting class 3, and an operating temperature range down to -40 °C and up to 70 °C.
Rated for 230/400 V AC with a 50/60 Hz supply frequency range, the 5SY4120-6 offers a 10 kA short-circuit breaking capacity to EN 60898-1, with additional performance ratings in accordance with IEC 60947-2. The compact, single-module (18 mm) format mounts via a quick assembly system on standard DIN rail and supports flexible installation orientation. Combined terminals top and bottom simplify panel wiring, accommodating solid or stranded conductors from 0.75 to 35 mm² (and finely stranded with end processing up to 25 mm²), with a recommended tightening torque of 2.5 to 3.5 N·m.
Built for demanding industrial environments, it is halogen-free, sealable and silicon-free, with IP20 protection (with connected conductors), energy limiting class 3, and an operating temperature range down to -40 °C and up to 70 °C.
| Specification | Description |
|---|---|
| Manufacturer | Siemens |
| Part Number | 5SY4120-6 |
| Alternative Part Number | 5SY41206 |
| Product Type | Miniature circuit breaker (MCB) |
| Product Range / Brand | SENTRON |
| Pole Configuration | 1-pole (1P) |
| Tripping Characteristic | Type B |
| Rated Current | 20 A (at 35 °C) |
| Rated Voltage (AC) | 230/400 V AC |
| Rated Frequency | 50/60 Hz |
| Maximum Operating Voltage (DC) | Up to 72 V DC |
| Insulation Voltage (Ui) | 440 V |
| Short-Circuit Breaking Capacity (EN 60898-1) | 10 kA |
| Switching Capacity (IEC 60947-2) | 20 kA |
| Switching Capacity (DC, IEC 60947-2) | 15 kA |
| Breaking Capacity (UL 1077 / CSA) | 5 kA |
| Energy Limiting Class | Class 3 |
| Power Loss (per pole) | 2.2 W (hot operating state) |
| Degree of Protection | IP20 (with connected conductors) |
| Overvoltage Category | III |
| Pollution Degree | 3 |
| Mechanical Service Life | Typical 10,000 operating cycles |
| Mounting Method | Quick assembly system (DIN rail mounting) |
| Mounting Position | Any |
| Width | 18 mm (1 modular width unit) |
| Height | 90 mm |
| Depth | 76 mm |
| Installation Depth | 70 mm |
| Net Weight | 165 g |
| Terminal Design | Combined terminals (top and bottom) |
| Solid Conductor Cross-Section | 0.75 to 35 mm² |
| Stranded Conductor Cross-Section | 0.75 to 35 mm² |
| Finely Stranded (with end sleeve) | 0.75 to 25 mm² |
| Connectable Conductor Size (AWG) | 18 to 4 AWG |
| Terminal Tightening Torque | 2.5 to 3.5 N·m |
| Neutral Conductor Switching | No |
| Additional Features | Sealable; touch protection; halogen-free; silicon-free; supplementary devices can be fitted |
| Applicable Standards | IEC/EN 60898-1; IEC/EN 60947-2; UL 1077 |
| Operating Ambient Temperature | -40 °C to +70 °C |
| Storage Ambient Temperature | -40 °C to +75 °C |
| Part Description | Siemens 5SY4120-6 SENTRON miniature circuit breaker, 1-pole Type B, rated 20 A for 230/400 V AC circuits, designed for compact DIN-rail installations where dependable overcurrent protection and straightforward panel layout are required. |
What is this device used for?
It is a miniature circuit breaker (MCB) used to provide overcurrent and short-circuit protection for electrical circuits in industrial and commercial control panels and distribution assemblies.
How many poles does it have?
It is a single-pole (1P) device, intended to switch and protect one live conductor.
What is the rated current?
The rated current is 20 A (at 35 °C). Like most MCBs, the permissible continuous current reduces as ambient temperature increases.
What tripping characteristic does it have, and when is it typically chosen?
It has a Type B tripping characteristic, commonly selected for circuits with low inrush currents such as general-purpose distribution, control circuits, and resistive loads.
What voltage systems can it be used on?
It is rated for 230/400 V AC systems and supports 50/60 Hz operation. It can also be used on DC up to 72 V (maximum operating voltage), subject to correct application and installation practices.
What is the short-circuit breaking capacity?
It provides 10 kA breaking capacity according to EN 60898 standards, and it is also specified with higher switching capacity figures under IEC 60947-2 (application-dependent).
Does it meet requirements for use as a main switch in control panels?
Yes. It is specified as having properties for main switches in accordance with EN 60204-1.
What ingress protection rating does it have?
It is rated IP20 when conductors are connected, meaning it is intended for installation within a suitable enclosure.
What are the physical dimensions?
Typical dimensions are 90 mm (height) × 18 mm (width, 1 modular unit) × 76 mm (depth), with an installation depth of 70 mm. Net weight is approximately 165 g.
How is it mounted?
It uses a quick assembly system for standard DIN rail mounting, and it can be installed in any mounting position.
What conductor sizes and terminal tightening torque are supported?
It accepts 0.75 to 35 mm² solid or stranded conductors, and 0.75 to 25 mm² fine-stranded conductors when fitted with appropriate end processing. Recommended screw terminal tightening torque is 2.5 to 3.5 N·m.
What are the permitted ambient temperature ranges?
Ambient temperature during operation is specified from -40 °C to +70 °C, and during storage from -40 °C to +75 °C.
Can it switch a neutral conductor?
No. This device does not provide neutral conductor switching.
Can accessories or supplementary modules be added?
Yes. It is designed to accept installable supplementary devices. If you need to match a specific function, it is best to confirm the required accessory type and the panel configuration; the base unit is commonly referenced as Siemens 5SY4120-6.
- Protecting single-phase branch circuits in industrial control panels operating at 230/400 V AC
- Overload and short-circuit protection for 20 A circuits supplying machinery auxiliaries and panel power distribution
- Circuit protection for DIN-rail mounted distribution within manufacturing and process equipment enclosures
- Providing a compact 1-pole protective device where a B-curve trip characteristic suits general-purpose loads
- Safeguarding control transformers, power supplies, and panel-mounted outlets on machine electrical systems
- Use as a local isolation and protection device for individual loads within modular electrical assemblies
- Application in electrical cabinets where touch-protected, IP20-with-conductors construction is required
- Integration into installations needing supplementary add-on modules for signalling or functional extensions
- Protecting circuits in environments with wide operating temperature ranges, including unheated plant areas
- Use in mechanical engineering and industrial installations requiring consistent protection coordination across multiple protected feeders
This content has been produced using multiple sources. EU Automation takes no responsibility for the accuracy of this information. Always consult the original equipment manufacturer for the most up to date instructions and information.
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Customer reviews
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Daniel
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Alex Bailey is my main point of contact at EU Automation...he is extremely friendly, has exceptional customer service skills and always offers great pricing & lead times.
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Tom Higgins did a great job at getting us the part we needed. He saw a concern with the part a verified before shipping.
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