Carlo Gavazzi Launches ATEX-Compliant Power Relay Series

Carlo Gavazzi Automation has added a new series of electromechanical relays for use in environments where flammable liquids, vapors, and dusts may be present. The CF/CS30 ATEX series relays are designed to meet several relevant standards for these hazardous zones.

Equipment for Potentially Explosive Atmospheres (ATEX)

Carlo Gavazzi’s new power relays feature ATEX approval and are designed for environments with concentrations of flammable vapors, liquids, or explosive dusts. These areas are often in need of automated process control and safety systems to minimize the amount of time workers are in these hazardous environments. However, standard electromechanical relays can arc upon changing states from open to closed and vice versa.

Carlo Gavazzi’s CF/CS30 series of electromechanical power relays features ATEX approval for use in potentially explosive environments. Image used courtesy of Carlo Gavazzi

This arc can be observed in the home by watching the light switch when it is flipped on: a small spark as the contact begins to close. In the home, this tiny spark may be of no consequence. In a manufacturing facility with flammable vapors, liquids, and dusts, that spark could be the ignition source for disaster.

The CS/CF 30 ATEX Series

The CS/CF 30 ATEX electromechanical power relays are available in two styles: CF Fast-on and soldered (CS) for PCB connections. The relays are available in various sizes, handling 6 VDC to 48 VDC and 24 VAC up to 277 VAC, depending on the specific model. All of the relays trip at 30 A and feature a 4 kV / 8 mm high-performance insulation to prevent arcing. The relays offer two changeover contacts (DPDT) and two normally open (DPST) contacts.

The CS/CF 30 series relays meet numerous standards, including ATEX (TÜV), CE, UL508, and NWFR (UL) that outline safe operation in flammable vapor environments. The relay bodies also pass the Glow Wire Test (GWT 750 ℃), which handles how a component performs against fires due to overheated wires.

The CF/CS30 ATEX series is suitable for use in HVACR equipment that utilizes flammable refrigerants. Image used courtesy of Adobe Stock

Flammable Refrigerant Safety

According to Carlo Gavazzi, this relay can be used in any sensitive area where flammables are present. More specifically, they envision these relays being deployed in areas where flammable liquids (and thus, flammable vapors) are used in coolant loops. In these applications, there is the ever-present need to cycle pumps, compressors, actuate valves, and perform other such tasks for maintaining temperature control.

Liquid propane (R290), for example, is a commonly used refrigerant in some cases, as it has a low freezing point and is not very corrosive. Even ammonia (R717) and ethylene glycol, a common radiator antifreeze, can be flammable under the right conditions and are both used as coolants in some industrial heat exchangers. Ultimately, any A2L or A3 listed refrigerant can be used safely with this relay.