McMaster-Carr

Upgrade motor starters that use thermal overload protection with these solid-state overloads—they don't use heating elements, so enclosure ventilation and cooling is not required.

AC Circuit Breaker Boxes and Circuit Breakers

High-Inrush DIN-Rail Mount
AC Equipment Circuit Breakers

Able to handle high inrush current caused by equipment startup, these circuit breakers are suitable for motor and larger transformer applications.

DIN-Rail Mount AC
Equipment Circuit Breakers

Use these circuit breakers with small transformers, lighting, and control circuits.

DIN-Rail Mount AC
Branch Circuit Breakers

Use these circuit breakers upstream from small transformers, lighting, and control circuits.

High-Inrush DIN-Rail Mount
AC Branch Circuit Breakers

Able to handle high inrush current caused by equipment startup, use these circuit breakers upstream from motors and larger transformer applications.

Space-Saver Panel-Mount
AC Branch Circuit Breakers

Small enough to fit in tight spaces, these UL 489-rated circuit breakers provide branch circuit protection.

High-Temperature Panel-Mount
AC Circuit Breakers

These magnetic circuit breakers are unaffected by temperature changes and trip when the magnetic field in the coil increases from current overload, so they are suitable for high-temperature environments.

Plug-Base Circuit Breakers

Replace any Edison-base fuse with these resettable circuit breakers.

Square D Load-Center
Circuit Breakers

Match these circuit breakers to Square D breaker boxes or panel boards of the same manufacturer series.

Siemens Load-Center
Circuit Breakers

Use with Siemens EQ series breaker boxes.

Cutler-Hammer Load-Center
Circuit Breakers

Install these circuit breakers into Cutler-Hammer CH series breaker boxes.

Square D Homeline
Circuit Breaker Boxes

Use these boxes with Homeline series circuit breakers and connect them to a main box—they do not have a main circuit breaker switch.

Square D Main Circuit Breaker Boxes

These boxes have a main circuit breaker switch and main service knockouts in the corners. Use with Square D QO series circuit breakers.

Square D Secondary
Circuit Breaker Boxes

Connect these boxes to a main box—they do not have a main circuit breaker switch. Use with Square D QO series circuit breakers.

DC Circuit Breakers

Vibration-Resistant Blade-Style
DC Circuit Breakers

These circuit breakers resist vibration better than standard low-voltage DC circuit breakers.

Harsh-Environment
DC Circuit Breakers

Built to resist vibration and corrosion in harsh enviornments.

Blade-Style DC Circuit Breakers

Protect against overload and short circuits in low-voltage automotive and other electronic applications.

Blade-Style High-Voltage
DC Circuit Breakers

Rated to 72V DC, these can handle higher voltages than any other DC circuit breaker we offer.

AC/DC Circuit Breakers

Panel-Mount AC/DC Circuit Breakers

In addition to protecting equipment, these circuit breakers can be used as on/off switches. They can handle high inrush current found in motor start-ups.

High-Temperature Panel-Mount
AC/DC Circuit Breakers

These magnetic circuit breakers are unaffected by temperature changes so they are suitable for high-temperature environments. They trip when the magnetic field in the coil increases from current overload.

Current Limiters

Also known as thermistors, these devices protect power supplies, motor drives, and battery chargers from large inrush currents when the equipment is turned on.

Torque Limiters for Chain and Belt Drives

Torque Limiters for
Chain and Belt Drives

Prevent damage from overloading. When overloaded, these limiters cause your sprocket or pulley to slip. Once the overload is removed, the limiters automatically reset.

Surface-Mount GFCIs

Mount and hardwire one of these GFCIs to your equipment to provide ground fault protection.

Adjustable Torque-Limiting Socket Adapters

Adjustable Torque-Limiting
Socket Adapters

Set a desired torque within the range.

Torque-Limiting Shaft-to-Gear Couplings

Magnetic Torque-Limiting
Shaft-to-Gear Couplings

Also known as hysteresis clutches, these couplings use magnetic force to brake, control tension, and prevent torque overload. They have few moving parts, so they last longer than mechanical couplings.

Magnetic Torque-Limiting
Shaft-to-Gear Couplings with Shaft

Also known as hysteresis clutches, these couplings use magnetic force to brake, control tension, and prevent torque overload. They have a shaft on one end for connecting to other components.

Electromagnetic Torque-Limiting
Shaft-to-Gear Couplings

Use these with an overload sensor in an automated system to instantly disconnect power and prevent damage. Couplings also accelerate loads from zero to full speed in less than three milliseconds when the power is turned on.

Electromagnetic Tensioning, Holding,
and Stopping Shaft-to-Gear Couplings

Also known as electric hysteresis brakes, these couplings use magnetic force to create drag to slow or stop the motion of your drive system.

Torque-Limiting
Shaft-to-Gear Couplings

Adjust your system's torque limit by hand.

Air-Powered Torque-Limiting
Shaft-to-Gear Couplings

Often used in automated systems, these couplings are both air actuated and remotely adjustable, so you can adjust the torque setting even during operation.

Torque-Limiting Shaft-to-Shaft Couplings

Torque-Limiting Flexible
Shaft Couplings with Alarm

If they exceed maximum torque, these couplings disengage, sound an alarm, and then automatically re-engage once the overtorque condition is eliminated.

Torque-Limiting Flexible
Shaft Couplings

Protect shafts, motors, and gear boxes from damage that’s caused by torque overload from machine jams and emergency stops.

Torque-Limiting Shaft Couplings

Adjust your system's torque limit by hand.

Air-Powered Torque-Limiting
Shaft Couplings

Often used in automated systems, these couplings are air actuated so you can adjust the torque during operation.

Enclosure-Mount Aluminum Power and Data Outlet Boxes

Enclosure-Mount Aluminum
Power and Data Outlet Boxes

Mount these boxes to the outside of an enclosure to access a programmable logic controller or other networked device without opening the enclosure.

NEMA Straight-Blade Plugs, Sockets, and Receptacles

Surge-Suppressing DIN-Rail
Mount Straight-Blade Receptacles

Prevent damage to electronic equipment caused by spikes in current. Mount these receptacles to DIN rail.

GFCI Straight-Blade Receptacles

Install these receptacles indoors. They keep personnel safe from electric shock by adding ground fault protection.

Weather-Resistant GFCI
Straight-Blade Receptacles

Suitable for use outdoors, receptacles can be used in wet and damp environments. They keep personnel safe from electric shock by adding ground fault protection.

GFCI DIN-Rail Mount
Straight-Blade Receptacles

Keep personnel safe from electric shock by adding ground fault protection to all outlets on the same circuit. These receptacles mount to DIN rail.

GFCI Sure-Grip
Straight-Blade Receptacles

Keep personnel safe from electric shock by adding ground fault protection. These receptacles have an extra-tight fit when mated with plugs to withstand high vibration. Also known as hospital grade receptacles.

Cords

GFCI Turn-Lock Extension Cords

Keep personnel safe from electric shock with these cords.

GFCI Extension Cords

Keep personnel safe from electric shock with these cords.

GFCI Outlet Splitters

Turn a single outlet into five outlets with ground fault protection to minimize the risk of electric shock.

Extension Cord GFCI Converters

Hardwire one of these converters to an extension cord to keep personnel safe from electric shock.

GFCI Outlet Adapters

Minimize the risk of electric shock by adding ground fault protection to a standard outlet.