Siemens 5SN7G16A Miniature Circuit Breaker – SENTRON 5SN Series

Siemens 5SN7G16A — 16A Single-Pole Type G MCB in Low-Voltage Branch Circuit Protection Architecture

The Siemens 5SN7G16A is a 16A, 1-pole miniature circuit breaker (MCB) belonging to the SENTRON 5SN product family. It is designed to provide overcurrent and short-circuit protection in low-voltage distribution networks operating at up to 230/400 V AC, 50/60 Hz. The Type G tripping characteristic — defined under IEC 60898-1 with an instantaneous trip threshold of 8–15× rated current (I_n) — makes this device specifically suited for branch circuits supplying motor loads, control transformers, and inductive actuators where high inrush currents are inherent to normal operation.

Within a PLC-based control architecture, the 5SN7G16A is typically positioned at the sub-distribution level: downstream of a main MCCB or RCCB, and upstream of 24 VDC SITOP power supply units, I/O module racks, or field device terminal strips. Its 35 mm DIN rail mounting (EN 60715) allows direct integration into standard Rittal, Hoffman, or Siemens ALPHA distribution boards without additional adapters.

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Technical Parameters

Hardware Logical Analysis

The 5SN7G16A employs a dual-element trip mechanism combining a bimetallic thermal strip for overload detection and a magnetic solenoid for instantaneous short-circuit response. The thermal element operates on the Joule heating principle: sustained overcurrent causes differential thermal expansion in the bimetal strip, deflecting it until it releases the trip latch. Response time is inversely proportional to the magnitude of overcurrent — a characteristic that provides inherent coordination with downstream fuses or terminal blocks.

The magnetic trip element uses a fixed-core solenoid. When fault current exceeds the Type G threshold (8–15 × I_n), the electromagnetic force generated by the solenoid plunger overcomes the latch spring force within milliseconds, opening the contact bridge before the fault arc can sustain. The contact system uses silver-alloy (AgNi or AgSnO₂) contact tips, which exhibit low contact resistance under normal load and high arc erosion resistance during fault interruption.

EMC performance is addressed through the compact, enclosed housing geometry. The arc quenching chamber — a stack of steel de-ionizing plates — rapidly cools and segments the fault arc, reducing arc voltage and limiting electromagnetic emissions during interruption. This design keeps conducted and radiated interference within the bounds required for operation alongside sensitive PLC CPUs and analog signal conditioning modules in the same enclosure.

The 1-pole configuration means the neutral conductor is not switched. In TN-S grounding systems, this is standard practice for branch circuit protection where the neutral is bonded at the distribution board. For IT network applications requiring pole-neutral switching, the 2-pole 5SN variant should be specified instead.

The DIN rail snap-fit mechanism uses a spring-loaded retention clip that maintains a minimum 50 N retention force, preventing vibration-induced displacement in mobile or high-vibration industrial environments such as machine tool enclosures or transportation control cabinets.

System Integration Benefits

• Selective Coordination with Upstream Devices: The Type G time-current curve is engineered to coordinate with upstream Type B or Type C MCBs and MCCB devices, ensuring only the faulted branch trips while the main feeder remains energized — preserving system uptime in multi-branch panels.
• Motor Inrush Tolerance Without Nuisance Tripping: The 8–15 × I_n instantaneous band accommodates the 6–10 × I_n inrush of standard IEC motors and control transformers, eliminating spurious trips during normal start sequences.
• Direct Compatibility with Siemens SENTRON Accessories: The 5SN7G16A accepts the full range of 5ST3 auxiliary contact blocks, 5SY shunt trip coils, and 5SN comb busbars — enabling remote status monitoring and centralized trip signaling without panel rewiring.
• Deterministic Fault Clearance Time: The magnetic trip mechanism provides sub-10 ms fault clearance at currents above the instantaneous threshold, limiting let-through energy (I²t) to levels safe for 1.5 mm² and 2.5 mm² copper conductors typically used in control panel wiring.
• Diagnostic Transparency via Auxiliary Contacts: When paired with a 5ST3 auxiliary contact block, the trip status is converted to a dry-contact signal readable by a PLC digital input module, enabling automated fault logging and alarm generation in SCADA or TIA Portal-based systems.
• Compact Panel Footprint: At approximately 17.8 mm wide per pole, the 5SN7G16A allows high-density installation in 12-module or 18-module DIN rail enclosures, supporting up to 20+ branch circuits in a standard 400 mm wide panel.
• Consistent Trip Accuracy Across Temperature Range: The bimetal calibration accounts for ambient temperature compensation, maintaining rated trip accuracy from -25 °C to +55 °C — critical for outdoor enclosures and unheated industrial buildings.
• Long-Term Spare Parts Availability: As part of the established SENTRON 5SN series, this MCB benefits from Siemens’ documented long-term product availability policy, reducing obsolescence risk for maintenance-critical installations with 10–20 year operational horizons.

Quality Assurance & Global Logistics

Every unit of the Siemens 5SN7G16A supplied through siemensplc.com is sourced from verified industrial distribution channels and undergoes a structured pre-shipment inspection protocol. Visual authentication checks confirm OEM labeling integrity, date code consistency, and factory packaging seals. Functional continuity verification is performed on each unit prior to dispatch. Anti-counterfeit cross-referencing against Siemens authorized part databases is conducted as a standard step in the sourcing workflow.

Shipments originate from our warehouse in Xiamen, China — a major international logistics hub with direct access to DHL Express, FedEx International Priority, UPS Worldwide Express, and SF International freight lanes. Standard in-stock orders are processed and dispatched within 1–3 business days. Express delivery to Europe, North America, Southeast Asia, and the Middle East typically achieves door-to-door transit times of 3–7 business days depending on destination customs clearance.

Full export documentation is provided with every international shipment: commercial invoice, detailed packing list, and Certificate of Origin (CO) for customs clearance. Certificates of conformity and test reports are available upon request for project documentation and third-party audit requirements. All units are packed in anti-static, moisture-resistant packaging suitable for air freight and sea freight conditions.

A 12-month warranty from the date of shipment covers manufacturing defects and confirmed authenticity. Warranty claims are processed with direct technical support from our engineering team in Xiamen.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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