Siemens 5sj4240-7hg42 40A 240V 2 Pole Miniature Circuit Breaker

Product Description

The SIEMENS 5sj4240-7hg42 is a Sentron Type NSJ miniature circuit breaker rated for 240 volts AC at 40 amps, designed for 2-pole, single-phase overcurrent protection in low-voltage electrical distribution systems. It features thermal magnetic trip action, providing both overload and short-circuit protection in a single compact device. The breaker is rated for a 14 kA interrupt capacity and operates at 50 Hz. It mounts on a standard DIN rail and accepts line, load, and screw-type connections. Licensed electricians working on commercial panels, distribution boards, and industrial control enclosures are the primary installers of this device.

This circuit breaker is suited for residential, commercial, and light industrial panel applications where DIN rail-mounted overcurrent protection is required. The handle actuator provides direct manual switching. Its IP20 enclosure rating makes it appropriate for use inside protected electrical enclosures and switchgear assemblies. The operating temperature range of -25 to 55 degrees C makes it viable across a wide range of installation environments, including unheated mechanical rooms and outdoor-rated enclosures where ambient temperatures remain within this range.

Key Features

• 40 amp continuous rating at 240 volts AC for robust overcurrent protection
• 14 kA interrupt capacity handles high fault-current environments
• Thermal magnetic trip responds to both sustained overloads and instantaneous short circuits
• 2-pole configuration for single-phase branch circuit protection
• DIN rail mounting for fast, tool-efficient installation in standard enclosures
• Accepts 14 to 4 AWG wire via screw-type line and load connections
• IP20 enclosure rating suitable for use inside protected switchgear assemblies

Compatibility

Designed as an OEM-style DIN rail miniature circuit breaker for use in standard switchgear enclosures, distribution boards, and industrial control panels that accept Type NSJ Sentron series breakers with 2-pole configurations.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the NEC and any applicable local codes. De-energize and lock out the panel or distribution board before installing or removing the breaker. Verify that wire gauge falls within the 14 to 4 AWG range before making screw-terminal connections and confirm torque requirements against the panel documentation or enclosure label. Do not exceed the rated voltage, amperage, or interrupt capacity of this device.

Technical Specifications

• Type: NSJ Sentron Miniature Circuit Breaker
• Voltage Rating: 240 volts AC
• Amperage Rating: 40 amps
• Frequency: 50 Hz
• Interrupt Capacity: 14 kA
• Trip Type: Thermal Magnetic
• Poles: 2
• Phase: 1
• Actuator Type: Handle
• Connection Type: Line/Load/Screw
• Wire Range: 14 to 4 AWG
• Enclosure Rating: IP20
• Mounting: DIN Rail
• Operating Temperature: -25 to 55 degrees C
• Dimensions (H x W x D): 4.76 inches H x 1.42 inches W x 2.76 inches D

Standard Information

• Brand: SIEMENS
• Manufacturer Part Number: 5sj4240-7hg42