Modular Installation Contactor ZAMEL STM-25-20 — 25A, 2 NO, 230V AC

ZAMEL STM-25-20 is a modular installation contactor designed for DIN-rail mounting in electrical distribution and control panels. It features a 25 A rated switching capacity, two normally open (2 NO) load contacts and a 230 V AC coil suitable for standard mains control. The device is intended to switch lighting circuits, small motors and resistive loads in residential and light-commercial automation and protection circuits.

Advantages

The contactor provides a compact DIN-rail form factor that saves panel space and integrates with common modular accessories. With a 25 A rating and dual normally open contacts it allows simple control of two circuits or doubled load paths from a single coil. The 230 V AC coil matches typical control voltages used in building installations, enabling direct connection to phase-controlled switches or automation outputs. The product is manufactured by ZAMEL, a supplier of electrical installation components, and is designed for straightforward installation and operation in standard distribution boards.

Suitable for

• Switching domestic and corridor lighting circuits
• Controlling small asynchronous motors and pumps within rated current
• Automation tasks in residential and light-commercial panels
• Resistive loads such as heaters and immersion elements within 25 A

When it may not be suitable

This modular contactor is not intended for high-power industrial applications that require switching currents significantly above 25 A or specialized contactors with auxiliary functions. It is also unsuitable where DC coil operation is required, as the coil is specified for 230 V AC. For loads with high inrush currents, harmonic distortion, or reactive power beyond typical small motors, evaluate contactor sizing and protective measures before use.

Key specifications

• Rated switching current: 25 A
• Contact configuration: 2 normally open (2 NO)
• Coil voltage: 230 V AC
• Mounting: DIN-rail (modular form factor)
• Typical applications: lighting, small motors, resistive loads

How to use

Mount the STM-25-20 on a standard DIN-rail inside the distribution or control panel and connect supply and load conductors to the designated input and output terminals following local wiring regulations. Connect the 230 V AC control supply to the coil terminals; ensure control wiring is de-energized during installation. Use appropriate overcurrent protection upstream of the contactor sized to the connected loads and the contactor rating. Verify correct operation by energizing the coil and confirming switching of the intended circuits.

What to consider before purchase

• Confirm the total continuous and starting current of connected loads does not exceed 25 A per contactor.
• Ensure control voltage in your system is 230 V AC compatible with the coil.
• Check available DIN-rail space and terminal clearances in your panel.
• Plan for appropriate upstream circuit protection and thermal considerations for grouped loads.

Usage recommendations

For reliable service, use the contactor within rated limits, provide proper short-circuit and overload protection, and follow local electrical codes. When switching motors or inductive loads, consider using an appropriate protective relay or soft-start device to limit inrush currents and extend contact life.