Terminal Relays | McMaster-Carr

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.

DIN-Rail Mount Solid State Interface Relays

With no moving parts, these solid state relays last longer, switch faster, and are quieter than mechanical relays. They interface between your controller and components to isolate input and output circuits, which protects components from voltage spikes, amplifies the relay’s signal, and reduces interference for reliable transmission.

DIN-Rail Mount Touch-Safe Screw Terminal Relays

Quickly and safely mount these relays on 35 mm DIN rail (also known as DIN 3). IP20 rated, they have recessed terminals that prevent fingers and other objects from touching live circuits.

Circuit Board Relays

Smaller than relays with electrical wiring, these relays fit in compact devices. Mount them through holes on circuit boards with their solder pin terminals.

Open-Style Screw Terminal Relays

Use these relays with industrial automation systems, security and emergency lighting, and small motors.

Solid State Screw Terminal Relays

With no moving parts, these solid-state relays are fast switching and require less maintenance, last longer, and are quieter than mechanical switches.

Screw Terminal Relays

Use the screw terminals to hardwire these relays.

Infrequent-Cycle Relays

For use with equipment that cycles on and off, these relays meet UL 508 for air conditioning and heating. Also known as definite-purpose contactors.

Spade-Terminal Relays

Using a low-current signal, these relays are often used to control small motors and heaters.

Solid State Spade-Terminal Relays

Often used for high-speed switching at low-current levels, these solid state relays have no moving parts, so they switch faster, last longer, and are quieter than mechanical switches.

Water-Resistant Stud-Terminal Relays

Sealed to keep out water, these relays are often used for DC-powered equipment such as forklifts, floor scrubbers, and trucks.

Stud-Terminal Relays

Suitable for DC-powered equipment such as forklifts, floor scrubbers, and trucks.

Circuit Board Safety Relays

Reduce connection errors on circuit boards that control machine guards and other safety devices. These relays take up less space on a board than those with electrical wiring because their solder pin terminals mount directly through circuit board holes.

Safety Relays with Diagnostic Capabilities

Control and diagnose issues with safety-critical circuits.

Safety Relays

Receive signals from safety monitoring relays or controllers to switch devices off and on because of a system failure.

Machine-Guard Relays

The interlocked opposing contacts won't close at the same time, so these relays are suitable for safety applications such as machine guarding.

Interface Safety Relays

These relays pair the transmission reliability of an interface relay with the fail-safe operation of a safety relay. They have interlocking contacts—also known as force-guided or mechanically linked contacts—so opposing contacts won't close at the same time.

Hazardous Location Relays

Sealed for safety, these relays are a good choice for hazardous locations where combustible or corrosive gases may be present.

Touch-Safe DIN-Rail Mount Infrequent-Cycle Relays

Operate equipment that cycles on and off from your control cabinet.

Sequenced Latching Relays

These relays switch through a series of different circuit configurations every time they receive an input voltage. Also known as step relays.

Air-Actuated Relays

Also known as an air-to-electric switch, this relay converts an air signal to an electric signal.

Analog-Input Proportional-Control Relays

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.

Network-Enabled Relays

With a built-in web server, these relays can be remotely controlled over any IP network, including the Internet.

Voltage-Monitoring Relays

Safeguard your equipment against overheating, wear, and malfunction from a spike or dip in voltage.

Frequency-Monitoring Relays

Prevent changes in frequency from damaging sensitive equipment.

Multifunction Monitoring Relays

Monitor phase, voltage, and frequency at the same time to protect motors, generators, and other three-phase circuits from burning out or overheating.

Current-Monitoring Relays

Protect electrical equipment from overcurrent and undercurrent damage—these relays continuously monitor current flow.

Smart Multifunction Monitoring Relays

Remotely control these relays through an app on your smartphone—they simultaneously monitor phase, voltage, and frequency.

High-Current Lighting Relays

Switch lighting systems on and off—these relays can handle the high switching current on large overhead light systems.

Ground-Fault Monitoring Relays

Detect and mitigate ground faults to prevent harm to equipment, circuits, and people.