Metal-Enclosed Drawout

Class 6037 / Refer to Catalog 6037CT9901

Power-Zone™ 4 Low Voltage Switchgear with Masterpact™ Circuit Breakers

Power-Zone 4
Low Voltage Switchgear
(Class 6037)

Square D™ brand Power-Zone™ 4 low voltage, metal-enclosed, drawout switchgear is designed to provide superior electrical distribution, protection, and power quality management. The prime components of the switchgear are the Masterpact™ NW and NT ANSI rated circuit breaker. Power-Zone 4 switchgear is designed to maximize the functionality of the Masterpact circuit breakers, which, in turn, deliver maximum uptime, system selectivity, ease of maintenance, and reliable circuit protection. All of these features are packed into the smallest footprint available for low voltage drawout switchgear.

  • Power-Zone 4 is designed and built to ANSI® C37.20.1 and is Listed to UL 1558

  • Masterpact NW and NT drawout low voltage power circuit breakers are designed and built to ANSI C37.13 and C37.16. Listed to UL 1066

  • Short-circuit current rating up to 200 kA at 240 V and 480 V without fuses

  • High short-time withstand ratings up to 100 kA for 1 second, minimum

  • Arc flash limiting (L1F) Masterpact NW feeder breakers available in 800, 1600, and 2000 A ratings

  • Family of field installable and upgradeable Micrologic™ trip units with optional Powerlogic™ data communications features

  • Power-Zone 4 switchgear can offer optional data communications capability

  • Smallest equipment footprint available in this product class

  • Front access to all control and communications wire connections

  • Bolted copper bus provided as standard
    (up to 6000 A maximum)

  • Large rear cable compartment pull area allowing maximum room for power cables

  • Horizontal bus provision for future equipment expansion

  • System designed for maximum uptime with low maintenance

  • Modular circuit breaker designed for easy addition of control accessories

  • Available in NEMA 3R outdoor walk-in enclosures

  • Available Arc Resistant construction certified to ANSI C37.20.7. See Power-Zone™ 4 Arc Resistant Switchgear with ArcBlok Technology.

Masterpact NW circuit breakers are available in various levels of interrupting ratings from 42–200 kA at 480 V and 130 kA at 600 V.

The Masterpact NT circuit breaker is available in an 800 A frame size and 42 kA at 480 V interrupting rating. Up to 8 Masterpact NT circuit breakers can be mounted in a 30-inch wide section. (Not available for 600 V.)

Circuit breakers of like frame sizes and interrupting ratings are interchangeable.

Masterpact Circuit Breaker Selection

Rating (A)

Catalog No.

Rating (A)

Catalog No.

Masterpact NW







































Masterpact NT




Power-Zone™ 4 Arc Resistant Switchgear with ArcBlok Technology

Arc Resistant Power-Zone 4
Low Voltage Switchgear
(Class 6037)

Protecting Your Personnel and Equipment from an Arc Flash

Power-Zone 4 arc resistant switchgear with Masterpact NW ArcBlok technology offers patented, superior arc flash protection for operators and maintenance personnel. The arc flash containment features are unique to the industry in both the circuit breaker compartment and the structure.

Power-Zone 4 Arc Resistant Switchgear with ArcBlok Technology is certified to comply with ANSI C37.20.7 IEEE Guide for Testing Metal-Enclosed Switchgear Rated Up to 38 kV for Internal Arcing Faults, and third-party (UL) witnessed as arc resistant switchgear. Refer to Data Bulletin 6037DB1302 for the complete UL Witness Certification Summary.


  • Masterpact NW circuit breakers with patented ArcBlok technology (up to 5000 A)

  • Rated for systems with up to 100kA, 635V fault current

  • 60 in. (1524 mm) deep x 22 in. (559 mm) wide (smallest arc resistant footprint in the industry)

  • 22 in. (559 mm), 36 in. (914 mm) section widths

  • 60 in. (1524 mm), 72 in. (1829 mm), 80 in. (2032 mm) section depths

  • Internal arc gas management system for optimized cooling

  • ANSI Type 2B Rating

  • NEMA 1 enclosures

Available Options

  • Insulated copper bus

  • Zone selective interlocking

  • High-resistance grounding

  • Energy reduction maintenance switch

  • Section barriers (rear, cable, and side)

  • Circuit breaker remote racking

  • ANSI Type 2B rated arc plenum exhaust

Micrologic™ Trip Units

A modern family of field-installable trip units is available with Masterpact NW and NT circuit breakers. The circuit breaker overcurrent protection consists of a microprocessor-based tripping device that requires no external power source. The complete tripping system has three main components: the air-core sensors, the trip device (with rating plug), and the trip actuator. The microprocessor-based trip unit uses true RMS current level sensing.

The Metering and Communications system is used in conjunction with Micrologic Type A, Type P, and Type H trip units (see Digest PowerPact P- and R-Frame Micrologic Trip Units and Micrologic™ Trip Unit Accessories ) for the Masterpact NW and NT circuit breakers. Modbus™ industry standard data communications allow this system to replace discrete meters, multiple transducers, analog wires, and analog-to-digital conversion equipment. Extensive information can be transmitted over a single communications cable to a Powerlogic system display, a personal computer, programmable logic controller, or other host system.

Basic circuit information, such as amperes, can be monitored using Micrologic Type A trip unit. Circuit breaker remote operation is available using the Micrologic Type P and Type H trip units with Powerlogic functionality. In addition to its metering capabilities, the Micrologic trip unit system is available with optional status inputs and relay outputs for monitoring discrete contacts and remote control of devices by way of the data communications channel.

Micrologic trip unit metering functions include:

  • Amperes and volts

  • Frequency

  • Power

  • Power demand

  • Energy

  • Energy demand

  • Power factor

  • Power quality measurements

  • Communications

  • Waveform capture

  • Data logging

  • Programmable contacts

  • Current unbalance

  • Over/under voltage

  • Over/under frequency

  • Voltage unbalance

  • Phase sequence

  • Reverse power

  • Long time imaging

  • Contact wear indicator

  • Masterpact circuit breaker maintenance information

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