METZ CONNECT KRA-SR-M8/21 Power Relay Module 21 V DC 1 CO 8 A White 11064513

Industrial automation often demands reliable switching of moderate loads with a clear visual status. The METZ CONNECT KRA-SR-M8/21 power relay module answers this need with a compact DIN-rail mountable design, a single changeover contact rated for 8 A, and a 21 V DC coil that operates with minimal power consumption. Its green LED gives immediate confirmation of coil energization, simplifying troubleshooting in control cabinets.

Who is it for

This relay module is built for panel builders, system integrators, and maintenance technicians who need a dependable interface between low-power control signals and higher-current loads. It suits HVAC controls, lighting circuits, motor contactors, and general automation tasks where space is limited but performance cannot be compromised.

Main features

• 1 changeover (SPDT) contact with silver-nickel (AgNi) alloy for long life
• Rated switching capacity: 8 A at 250 V AC or 30 V DC
• 21 V DC coil with only 0.2 W power draw, reducing heat and energy costs
• Green LED status indicator for at-a-glance operation check
• Screw terminals accept solid or stranded conductors up to 2.5 mm²
• Snap-on mounting for 35 mm DIN rail (EN 60715)
• Dielectric strength of 4 kV AC between coil and contacts
• Wide operating temperature range: -25 °C to +70 °C

Specifications

• Product type: Power relay module
• Contact configuration: 1 CO (SPDT)
• Rated switching voltage: 250 V AC / 30 V DC
• Rated switching current: 8 A
• Coil voltage: 21 V DC
• Coil power: 0.2 W
• Connection type: Screw terminals
• Mounting: DIN rail TS35
• Operating temperature: -25 °C to +70 °C
• Protection class: IP20
• Status indicator: Green LED
• Dielectric strength coil/contact: 4 kV AC
• Mechanical life: 10 × 10⁶ cycles
• Electrical life (rated load): 100 × 10³ cycles
• Contact material: AgNi
• Housing material: Polyamide (PA)
• Dimensions (W × D × H): 6.2 × 90 × 55 mm
• Weight: 0.03 kg

Tips

Always verify coil polarity when wiring the 21 V DC supply to avoid damage. For inductive loads such as small motors or solenoids, consider adding a flyback diode across the coil to suppress voltage spikes. The module’s compact 6.2 mm width allows high-density packing on the DIN rail, but leave adequate spacing for heat dissipation in high-current applications.