For use with equipment that cycles on and off, these relays meet UL 508 for air conditioning and heating. Connections are accessible from the front, so you can mount relays side-by-side. Also known as definite-purpose contactors.

Enclosures (sold separately) are NEMA 1 rated to protect contacts from corrosion.

Also Available: Auxiliary contacts for 3.8"-7.2" Ht. relays. They allow you to add a signaling device or control another relay. Please select 6564K99, then select the McMaster-Carr part number of your relay and whether you want to switch one circuit on (1 Normally Open) or off (1 Normally Closed).

For technical drawings and 3-D models, click on a part number.

Unlike mechanical relays, these solid state relays have no moving parts, so they require less maintenance and last longer, switch faster, and are quieter. They mount on 35 mm DIN rail (also known as DIN 3) for fast installation. IP20 rated, their terminals are recessed, so they prevent fingers and other objects from touching live circuits.

Relays with an integrated heat sink disperse heat to increase the relay’s current rating.

Relays with an integrated fan are best for applications that generate more heat. The fan automatically turns on to provide additional cooling. When the temperature exceeds 176° F, an alarm sends a signal to an external device, such as a controller or indicating light.

For technical drawings and 3-D models, click on a part number.

Operate equipment that cycles on and off from your control cabinet. Often called definite-purpose contactors, these relays meet UL 508 for use with air conditioning and heating. They mount directly to 35 mm DIN rail (also known as DIN 3 rail) for fast installation. These relays have recessed terminals that prevent fingers and other objects from touching live circuits.

Auxiliary contacts (sold separately) allow you to add a signaling device or control another relay.

For technical drawings and 3-D models, click on a part number.

Often used to regulate the speed of AC fans or keep a heater at a set temperature, these relays connect directly to sensors to calculate and adjust output power. This allows you to use an analog input without converting it to a digital signal to control output power. They are solid state and have no moving parts, so they require less maintenance and last longer, are quieter, and switch faster than mechanical relays. IP20 rated, they have recessed terminals that prevent fingers and other objects from touching live circuits. An integrated heat sink disperses heat to increase the relay’s current rating. The LED indicator shows input voltage loss and internal relay faults, so you can easily check that your system is operating properly.

Mount them on 35 mm DIN rail (also known as DIN 3 rail) for fast installation. They also mount to flat surfaces.

All relays have phase-angle switching to accurately control all types of loads. This mode signals at non-zero voltage, which can produce electrical noise. Choose relays with full-cycle switching for resistive loads. This mode signals at zero voltage, so electrical interference is lower than phase-angle switching.

Single-phase relays can be set to switch every 1, 4, or 16 cycles. When used with infrared heaters, they have an option to switch at the half cycle and again at the full cycle. When switching at 16 cycles or at the half cycle, these relays have a soft-start option to increase the output slower in high-inrush current applications.

Three-phase relays switch every cycle.

Relays with a potentiometer input can connect to an external potentiometer for manual control.

Relays with over-temperature protection stop power when it gets too hot and keeps it off until the issue is resolved. Connect an auxiliary contact (not included) to signal an alarm or status controller.

Relays with short-circuit protection stop power if there is an open circuit, short circuit, or output voltage loss until the issue is resolved. Connect an auxiliary contact (not included) to signal an alarm or status controller.

For technical drawings and 3-D models, click on a part number.