Siemens Sentron MD Frame Breakers for Industrial Power

Siemens Sentron MD Frame breakers designed for panel systems, switchboards, or motor control centers

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Table Of Contents
  1. Commercial or industrial power distribution
  2. Sentron MD Frame Breaker
  3. Large motors, downstream feeder sections
  4. Short-circuit protection, long-term overload protection
  5. Siemens and legacy ITE switchboards
  6. Built into UL 891 switchboards
  7. Long history of being dependable

Commercial or industrial power distribution

Switchboards, panelboards, motor control centers, and big feeder applications

Electrical systems needs dependable feeder protection

You’ve probably come across a Siemens Sentron breakers if you are working with major commercial or industrial power distribution equipment. In switchboards, panelboards, motor control centers, and big feeder applications where greater ampacity and dependable protection are essential, these molded case circuit breakers are often used.

Because Siemens/ITE breakers offer reliable performance, adaptable protection options, and integration with Siemens distribution equipment already in use in North American facilities, the MD Frame series has been used effectively for many years.

Sentron MD Frame Breaker

for commercial and industrial power distribution networks.

What Is a Siemens Sentron MD Frame Breaker?

The Siemens Sentron MD Frame breaker is a high-amperage molded case circuit breaker for commercial and industrial power distribution networks. Large feeder circuits in switchboards, distribution sections, and motor control centers are often protected by MD Frame breakers.

Sentron circuit breakers are popular because they give you dependable overcurrent protection while fitting inside compact electrical equipment layouts. Instead of moving up to much larger power circuit breakers, facilities use MD Frame breakers to handle higher-current applications efficiently.

The MD Frame family is part of the broader Siemens Sentron breaker platform, recognized throughout the electrical industry.

Specification Typical MD Frame Ratings
Frame Type MD Frame
Amp Range 600A to 800A
Voltage Rating Up to 600VAC
Pole Configurations 2 Pole / 3 Pole
Trip Styles Thermal Magnetic / Electronic
Interrupt Ratings Varies by model
Mounting Fixed Mounted
Applications Feeders, mains, industrial distribution

Before selecting a replacement breaker, you’ll typically want to verify the breaker frame size, AIC rating, voltage class, and trip configuration to ensure compatibility with your existing electrical equipment.

Large motors, downstream feeder sections

critical if you run a facility with continuous-process equipment

Sentron MD Frame Breaker Applications

Because Siemens MD Frame breakers provide dependable high-amperage feeder protection in a small molded case design, they are used in industrial and commercial applications.

MD Frame breakers are installed in manufacturing facilities for large motors, downstream feeder sections, HVAC distribution, and production equipment. Reliable feeder protection is critical if you run a facility with continuous-process equipment. Unplanned outages are costly.

Commercial buildings also rely on MD Frame breakers. Large office buildings, hospitals, retail facilities, and institutional campuses use them in electrical rooms serving mechanical loads, elevators, and tenant distribution systems.

MD Frame breakers are often built into UL 891 switchboards that handle UPS systems, cooling infrastructure, power distribution units, and generator connections if you work in data center power distribution.

Short-circuit protection, long-term overload protection

… more options when you use electronic trip breakers

Thermal Magnetic vs Electronic Trip Protection

One of the most significant decisions when choosing a Siemens MD Frame breaker is whether to use electronic trip prevention or thermal magnetic protection.

Because they are simple, reliable, and well-known to the vast majority of maintenance staff, traditional thermal magnetic breakers continue to be utilized extensively. Without requiring complex adjustment settings, these breakers offer both immediate short-circuit protection and long-term overload protection.

You have more options when you use breakers with electronic trip protection. Electronic trip units can improve selective coordination, provide customizable protection settings, and support optional ground fault prevention when working with complex coordination studies or important power systems

Catalog Number Amps Poles Description
HMD63B800 800A 3 Pole Thermal Magnetic
HMD63B700 700A 3 Pole Thermal Magnetic
MD63B800 800A 3 Pole Standard Industrial
LMD63B800 800A 3 Pole High Interrupting
MD63F600 600A 3 Pole Feeder Breaker
HMD23B600 600A 2 Pole Thermal Magnetic
LMD63F800 800A 3 Pole Electronic Trip

Siemens and legacy ITE switchboards

… easier and more cost-effective than replacing the entire switchboard lineup.

Replacement and Legacy Siemens MD Breakers

Many facilities still operate older Siemens and legacy ITE switchboards originally designed around MD Frame breakers. If you’re maintaining aging electrical infrastructure, finding compatible replacement breakers is easier and more cost-effective than replacing the entire switchboard lineup.

When replacing a legacy breaker, you’ll usually want to confirm:
Breaker frame dimensions
Mounting configuration
Voltage rating
Interrupting capacity
Bus connection compatibility
Trip unit type

Facilities use tested surplus or professionally reconditioned MD Frame breakers to keep existing equipment running while avoiding major capital upgrades.

Built into UL 891 switchboards

supporting bigger feeder circuits without significantly raising equipment footprint

MD Frame Breakers in UL 891 Switchboards

MD Frame breakers provide a compromise between small size and increased current capabilities, this breaker is built into UL 891 switchboards.

MD Frame breakers help with supporting bigger feeder circuits without significantly raising the equipment footprint required when developing or replacing a switchboard lineup. For this reason, they are still often used in data centers, utility systems, industrial sites, and medical campuses.

MD Frame breakers are compliant with current Siemens electrical distribution systems and provide variable feeder layouts for producers of custom switchboards.

Long history of being dependable

making compatibility, coordination, and long-term maintenance planning easier

Why Siemens MD Frame Breakers Remain Popular

Siemens Sentron MD Frame breakers are used by contractors and facility engineers for a reason.

They have a long history of being dependable in challenging electrical designs. Many facilities already have them installed, maintenance crews are familiar with them, and industrial electrical vendors offer a range of replacement alternatives.

Sticking with MD Frame breakers can make compatibility, coordination, and long-term maintenance planning easier if you’re extending or maintaining an existing Siemens power distribution system.

+ What is a Siemens Sentron MD Frame breaker?

A Siemens Sentron MD Frame breaker is a high-amperage molded case circuit breaker used for industrial and commercial feeder protection.

+ What amp range is available for MD Frame breakers?

Most MD Frame breakers are commonly available from 600 amps through 800 amps depending on the model.

+ Are Siemens MD breakers thermal magnetic?

Yes. Many Siemens MD breakers use thermal magnetic trip protection, although electronic trip versions are also available.

+ Can Siemens MD breakers be installed in switchboards?

Yes. MD Frame breakers are commonly installed in UL 891 switchboards, MCCs, and commercial distribution equipment.

+ What voltage are Siemens MD breakers rated for?

Many Siemens MD Frame breakers are rated for applications up to 600VAC.

+ Are replacement Siemens MD breakers still available?

Yes. Many tested surplus and reconditioned Siemens MD breakers remain available through industrial electrical suppliers.

+ What industries commonly use Siemens MD breakers?

Industries including manufacturing, healthcare, utilities, commercial construction, and data centers commonly use Siemens MD Frame breakers.

Term Definition
Molded Case Circuit Breaker (MCCB) Circuit breaker designed for overload and short-circuit protection.
MD Frame Siemens molded case breaker family used for higher ampacity applications.
Thermal Magnetic Trip Breaker protection using thermal and magnetic trip functions.
Electronic Trip Unit Adjustable electronic protection system used in advanced breakers.
AIC Rating Maximum fault current a breaker can safely interrupt.
UL 891 UL standard governing dead-front switchboards.
Switchboard Commercial or industrial electrical distribution assembly.
Feeder Breaker Breaker supplying downstream electrical equipment.
Motor Control Center (MCC) Assembly containing motor starters and power distribution equipment.
Selective Coordination Protection design allowing only the closest breaker to trip.