Wago Plug-in Relay Module 24V DC 5A 857-304

WAGO Plug‑in Relay Module 24V DC 5A 857-304

The WAGO 857-304 is a compact, high‑performance plug‑in relay module designed for reliable switching in industrial automation and control systems. It operates on a nominal input voltage of 24 VDC and can handle up to 5 A (or 6 A in some variants) at the output, making it suitable for a wide range of low‑voltage applications.

Key Technical Specifications

• Nominal Input Voltage: 24 VDC
• Coil Current: 10 mA
• Output Rating: 5 A (typical) / 6 A (extended)
• Maximum Output Voltage: 250 VAC or 30 VDC
• Relay Type: Single‑pole, single‑throw (SPST) changeover
• LED Indicator: Yellow LED on the module to show coil status
• Mounting Options: DIN rail or socket mounting for easy integration into control panels
• Dimensions: 35 mm width (standard plug‑in size)
• Operating Temperature Range: –25 °C to +70 °C (typical industrial range)

Design and Construction

The module features a rugged, metal housing that protects the internal components from dust, moisture, and mechanical shock. The plug‑in design allows for quick installation without soldering or additional tools, reducing downtime during maintenance or system upgrades.

Internally, the relay uses a single coil to energize an electromagnetic armature. When powered, the armature pulls the contact into the closed position, allowing current to flow through the output terminals. The yellow LED provides instant visual feedback of the coil state, aiding in troubleshooting and ensuring safe operation.

Application Areas

• Industrial Automation: Control of motors, pumps, and other low‑current devices.
• Building Management Systems: Switching HVAC components or lighting circuits.
• Process Control: Actuation of valves, solenoids, and safety interlocks.
• Testing Equipment: Quick switching for test rigs and measurement setups.

Installation Guidelines

1. Select the appropriate mounting method: For DIN rail installations, slide the module onto the rail; for socket mounting, insert it into a compatible terminal block.
2. Connect the input terminals: Wire the 24 VDC supply to the coil terminals. Ensure correct polarity and secure connections.
3. Wire the output terminals: Attach the load (motor, lamp, etc.) between the normally open (NO) and common (COM) contacts.
4. Verify LED status: When the coil is energized, the yellow LED should illuminate, indicating proper operation.

Safety Considerations

The module is designed to handle up to 250 VAC on its output. However, it is crucial to keep the load current within the specified limits (5 A/6 A) and avoid exceeding the voltage rating. Always disconnect power before performing maintenance.

Compatibility with WAGO Systems

The 857-304 integrates seamlessly into the broader WAGO ecosystem, including:

• WAGO 857-152 Slim Relay: For applications requiring a smaller form factor.
• WAGO JumpFlex Modules: Allows for flexible wiring and modular expansion.
• WAGO APE30024 Power Supply: Provides the required 24 VDC input with built‑in protection.

These combinations enable scalable, reliable automation solutions across various industries.

Maintenance Tips

• Inspect wiring connections periodically for corrosion or loosening.
• Clean the module’s exterior with a dry cloth; avoid abrasive cleaners that could damage the housing.
• Replace the module if the LED fails to illuminate when powered, as this indicates coil failure.

Conclusion

The WAGO Plug‑in Relay Module 24V DC 5A 857-304 offers a robust, easy‑to‑install solution for low‑voltage switching tasks. Its compact design, clear LED indication, and compatibility with the extensive WAGO product line make it an ideal choice for engineers seeking reliability and flexibility in control system design.