steve
Got hold of Sime for a Carrier card for…
Got hold of Sime for a Carrier card for a chiller. Machine down in a factory. Received the new card in express time machine and plant now up and running fantastic service form Sime
1 month ago
5SY4350-8
Siemens 5SY4350-8 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 5SY4350-8 (also referenced as 5SY43508) is a SENTRON 5SY4 miniature circuit breaker designed for dependable overcurrent protection in industrial and infrastructure electrical distribution. This 3‑pole, toggle‑operated MCB is rated at 50 A and 400 V AC with a D tripping characteristic, making it suitable for circuits with higher inrush currents such as motors, transformers and similar inductive loads. It provides a 10 kA breaking capacity to EN 60898 and 15 kA switching capacity to IEC 60947‑2, with IP20 touch protection when conductors are connected.
The 5SY4350-8 mounts via a quick assembly system and occupies 3 modular width units, with compact dimensions of 54 mm (W) x 76 mm (D) x 90 mm (H) and an installation depth of 70 mm. Combined terminals on both top and bottom support flexible wiring, accepting solid or stranded conductors from 0.75 to 35 mm² (fine-stranded with ferrules up to 25 mm²), with recommended terminal tightening torque of 2.5–3.5 N·m. The device is sealable, halogen‑free and silicon‑free, and supports installation of supplementary devices for added functionality where required.
The 5SY4350-8 mounts via a quick assembly system and occupies 3 modular width units, with compact dimensions of 54 mm (W) x 76 mm (D) x 90 mm (H) and an installation depth of 70 mm. Combined terminals on both top and bottom support flexible wiring, accepting solid or stranded conductors from 0.75 to 35 mm² (fine-stranded with ferrules up to 25 mm²), with recommended terminal tightening torque of 2.5–3.5 N·m. The device is sealable, halogen‑free and silicon‑free, and supports installation of supplementary devices for added functionality where required.
| Specification | Description |
|---|---|
| Manufacturer | Siemens |
| Part Number | 5SY4350-8 |
| Alternative Part Number | 5SY43508 |
| Product Type | Miniature circuit breaker (MCB) |
| Product Range / Brand | SENTRON, 5SY series |
| Number of Poles | 3 (3P) |
| Rated Current (In) | 50 A |
| Tripping Characteristic | D curve |
| Instantaneous (Magnetic) Trip Reference | Approx. 14 × In (reference value for I-tripping) |
| Rated Operational Voltage (AC) | 400 V AC |
| Rated Supply Frequency | 50/60 Hz |
| Rated Insulation Voltage (Ui) | 440 V |
| DC Operation (Maximum) | Up to 72 V DC (rated supply voltage 60 V DC) |
| Breaking Capacity (EN 60898) | 10 kA |
| Switching Capacity (IEC 60947-2) | 15 kA |
| Breaking Capacity (UL 1077 / CSA) | 5 kA |
| Protection Rating | IP20 (with connected conductors) |
| Overvoltage Category | III |
| Pollution Degree | 3 |
| Power Loss (per pole) | 3.7 W (at rated current, AC, hot operating state) |
| Mechanical Service Life | Typical 10,000 operating cycles |
| Mounting | Quick assembly system (DIN rail mounting) |
| Mounting Position | Any |
| Modular Width | 3 modules |
| Dimensions (W × D × H) | 54 × 76 × 90 mm |
| Installation Depth | 70 mm |
| Net Weight | Approx. 480 g |
| Terminal Design | Combined terminals: top and bottom |
| Neutral Conductor Switching | No |
| Touch Protection | Yes |
| Sealing Facility | Sealable |
| Material Properties | Halogen-free; silicon-free |
| Supplementary Devices | Supplementary devices can be installed |
| Conductor Cross-Section (Solid) | 0.75 to 35 mm² |
| Conductor Cross-Section (Stranded) | 0.75 to 35 mm² |
| Conductor Cross-Section (Fine-Stranded with ferrule) | 0.75 to 25 mm² |
| Connectable Conductor Size (AWG) | 18 to 4 AWG |
| Terminal Tightening Torque | 2.5 to 3.5 N·m |
| Ambient Temperature (Operation) | -40 to +70 °C |
| Ambient Temperature (Storage) | -40 to +75 °C |
| Typical Applications | Three-phase circuit protection in industrial and infrastructure electrical distribution, where higher inrush currents are expected (D-curve characteristic) |
What does this miniature circuit breaker do?
It provides overcurrent protection for electrical circuits by tripping on overloads and short circuits, helping to protect wiring and connected equipment in industrial and infrastructure installations.
How many poles does it have and what does that mean in practice?
It is a 3‑pole device, designed to switch and protect three conductors together (typically a three-phase circuit).
What is the rated current?
The rated current is 50 A (In). Temperature derating applies; for example, the operational current is specified as 48 A at 40 °C and 43.8 A at 60 °C.
What is the tripping characteristic and where is it commonly used?
It has D-curve tripping. D-curve breakers are typically selected for circuits with higher inrush currents (for example, certain motors and transformer-fed loads) where nuisance trips need to be minimised.
What is the rated voltage?
It is rated for 400 V AC operation (50/60 Hz). The insulation voltage (Ui) is specified as 440 V for single-phase and multi-phase AC operation.
What short-circuit breaking capacity does it provide?
Breaking capacity depends on the standard applied: it is rated 10 kA according to EN 60898, and 15 kA according to IEC 60947-2. For UL 1077/CSA C22.2 No.235, the AC breaking capacity is specified as 5 kA.
Can it be used on DC circuits?
It is specified for AC operation and also lists DC values: a DC supply voltage value of 60 V is stated, with a maximum DC operating voltage of 72 V. Suitability for a specific DC application should be confirmed against the full installation conditions.
How is it mounted in a control panel?
It uses a quick assembly system and is designed for standard modular mounting. Mounting position is specified as any.
What are the dimensions and installation depth?
Overall dimensions are approximately 90 mm (height) x 54 mm (width) x 76 mm (depth), with an installation depth of 70 mm. It occupies 3 modular width units.
What conductor sizes can be connected, and what tightening torque is recommended?
Typical connectable cross-sections are 0.75 to 35 mm² for solid and stranded conductors, and 0.75 to 25 mm² for finely stranded conductors with end processing. The specified tightening torque for screw terminals is 2.5 to 3.5 N·m.
Does it switch the neutral conductor?
No. Neutral conductor switching is specified as not included.
What ingress protection rating does it have?
It is rated IP20 with connected conductors.
What operating temperature range is specified?
Ambient temperature during operation is specified from -40 °C to +70 °C, and during storage from -40 °C to +75 °C.
Does it include features useful for panel builders, such as touch protection and sealability?
Yes. It is specified with touch protection and is sealable. It is also listed as halogen-free and silicon-free.
Can supplementary devices be added to the breaker?
Yes. It is specified as installable with supplementary devices (where compatible), which can be useful for expanding functionality within a panel build.
- Overcurrent and short-circuit protection for three-phase branch circuits in industrial control panels
- Protection of motor feeder circuits and high inrush current loads using a D tripping characteristic
- Isolation and switching of 3-pole circuits during maintenance and commissioning in machine electrical systems
- Protection of auxiliary power distribution in manufacturing lines, automation cells, and material handling equipment
- Circuit protection for three-phase HVAC components, pumps, and fans within commercial and industrial installations
- Protection of sub-distribution circuits in building services switchboards and electrical distribution boards
- Use in machinery and equipment panels requiring compact DIN-rail mounted circuit protection with high breaking capacity
- Protection of power circuits in infrastructure and industrial facilities operating on 400 V AC three-phase supplies
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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