electronic trip breakers

Electronic Trip Circuit Breaker Basics: Schneider Electric Micrologic Trip Units

What is electronic trip circuit breakers .

An electronic trip circuit breaker is a type of circuit breaker that uses electronic components to control the tripping mechanism instead of traditional thermal-magnetic trip elements. Electronic trip circuit breakers are commonly used in industrial and commercial applications where high reliability and selective coordination are required.

These circuit breakers use a solid-state trip unit to sense and respond to overcurrent conditions. The trip unit monitors the current flowing through the circuit breaker and can be programmed to trip at specific current levels and time delays. This allows for greater precision in protecting against overcurrent conditions and reduces the risk of nuisance trips. Electronic trip circuit breakers can also provide advanced monitoring and diagnostic capabilities. Some models can provide real-time current and voltage measurements, as well as fault event recording and reporting. This information can be used to identify potential issues and optimize system performance.

Related Article:  Circuit Breaker Essentials 

Why Use Electronic Trip Circuit Breakers? 

In most cases, the basic overcurrent protection provided by standard thermal-magnetic circuit breakers will meet the requirements of the electrical system design. In some cases, however, basic overcurrent protection might not be enough. Electronic trip circuit breakers can provide the additional features needed in those cases.

Reasons to use electronic trip circuit breakers includes:

• Enhanced coordination capabilities
• Integral ground-fault detection
• Communication capabilities
• Future growth potential

Enhanced Coordination Capabilities

Schneider electric micrologic electronic trip units.

• Independent adjustments  - allow one dial setting to be changed without affecting the rest of the pickup and delay levels. This allows the designer to better define the tripping characteristics needed on the system. 
• Interchangeable rating plugs-  allow the designer to shift the entire trip characteristic curve (except for ground fault) to improve coordination with other devices. MICROLOGIC rating plugs define the circuit breaker's maximum current rating based on a percentage of the circuit breaker sensor size and can be used on any frame size of circuit breaker within the MICROLOGIC family of circuit breakers. 
• Withstand ratings give the designer a larger window of coordination potential - The withstand rating is the level of rms symmetrical current that a circuit breaker can carry with the contacts in the closed position for a certain period of time. At current levels above the withstand rating (and less than or equal to the interrupting rating), the circuit breaker will trip instantaneously. In other words, the withstand rating is the highest current level at which delay can be introduced to maintain coordination with downstream devices. Withstand ratings are available only on full-function trip systems ordered with the adjustable short-time function.
• Inverse time delay characteristics  - allow for better coordination with fusible switches or thermal-magnetic circuit breakers downstream. Devices that respond to heat generated by current flow (such as fuses and thermal-magnetic circuit breakers) have inverse time tripping characteristics. This means that as current increases, the time that it takes the device to trip will decrease. In order to coordinate better with these types of downstream devices, MICROLOGIC circuit breakers offer inverse time delay characteristics on the long-time, short time and ground-fault functions. 
• Ammeter/trip indicator - displays the level of ground-fault leakage current associated with the circuit. The ground-fault pickup level on the circuit breaker may then be adjusted somewhat higher than the amount of leakage current displayed on the ammeter.

Integral Ground Fault Protection

Communication capabilities.

• History of last trip
• Trip unit pickup and delay levels
• Impending trip conditions
• Operating currents for each phase
• Ground-fault leakage current associated with the circuit
• Ground-fault alarm signal

Standard Function Trip Unit Curves

Long term trip function.

• LONG-TIME PICKUP Switch — switch value (multiplied by the ampere rating) sets the maximum current level which the circuit breaker will carry continuously. If the current exceeds this value for longer than the set delay time, the circuit breaker will trip. 
• LONG-TIME DELAY Switch — sets length of time that the circuit breaker will carry a sustained overload before tripping. Delay bands are labeled in seconds of overcurrent at six times the ampere rating. For maximum coordination, eight delay bands are available.

Short-time Trip Function

• SHORT-TIME PICKUP Switch — switch value (multiplied by the ampere rating) sets the short-circuit current level at which the circuit breaker will trip after the set SHORT-TIME DELAY.
• SHORT-TIME DELAY Switch — sets length of time the circuit breaker will carry a short circuit within the short-time pickup range. Delay bands are labeled in seconds of short-circuit current at 12 times the ampere rating, P. The short-time delay can be set to one of four I^2t ramp operation positions (I^2t IN).

Instantaneous Trip Function

• INSTANTANEOUS PICKUP Switch — switch value (multiplied by the ampere rating) sets the short-circuit current level at which the circuit breaker will trip with no intentional time delay. The instantaneous function will override the short-time function if the INSTANTANEOUS PICKUP is adjusted at the same or lower setting than the SHORT-TIME PICKUP. 
• GROUND-FAULT PICKUP Switch — switch value (multiplied by the sensor size) sets the current level at which the circuit breaker will trip after the set GROUND-FAULT DELAY.
• GROUND-FAULT DELAY Switch — sets the length of time the circuit breaker will carry ground-fault current which exceeds the GROUND-FAULT PICKUP level before tripping. Delay bands are labeled in seconds of ground-fault current at 1 times the sensor size, S. Ground-fault delay can be adjusted to one of four fixed time delay positions (I^2t OUT). 

In Comparison with Thermal Magnetic Circuit Breakers

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Micrologic 4 Electronic Trip Units

Introduction

The Micrologic 4 electronic trip unit is designed to protect:

o Conductors in commercial and industrial electrical distribution.

o Goods and people in commercial and industrial electrical distribution.

On 4-pole circuit breakers, neutral protection is set on the Micrologic trip unit by using a three-position dial:

o 4P 3D: neutral unprotected

o 4P 3D + N/2: neutral protection at half the value of the phase pickup, 0.5 x Ir (not available on Micrologic trip unit with In ≤ 40 A)

o 4P 4D: neutral fully protected at Ir

The Micrologic 4 electronic trip unit is available in two versions for earth-leakage detection:

o The Trip version trips when earth-leakage is detected.

o The Alarm version measures the earth-leakage current and indicates an earth-leakage fault on the front face with the earth-leakage fault indicator, which changes from gray to yellow.

When the SDx indication contact is present, it signals an earth-leakage fault remotely.

Description

The adjustment dials and indications are on the front face.

The trip unit rating In corresponds to the maximum value of the setting range.

Setting the Long-Time Protection

The long-time protection pickup Ir is set by using two multi-position dials.

o The preset dial allows the pickup to be preset to the value Io (displayed in amperes on the dial).

The maximum preset value (maximum setting on preset dial) equals the trip unit rating value In.

o The adjustment dial can be used to fine-tune the pickup Ir (value displayed in multiples of Io on the dial).

The time delay tr for long-time protection cannot be adjusted.

The following table shows the value of the time delay tr for long-time protection (in seconds) according to the overload current (in multiples of Ir)

The precision range is -20%, +0%.

Setting the Short-Time Protection

The short-time protection pickup Isd is set by using a multi-position dial.

The setting value is expressed in multiples of Ir.

The precision range is +/- 15%.

The time delay tr for short-time protection cannot be adjusted:

o Non-trip time: 20 ms

o Maximum breaking time: 80 ms.

Setting the Instantaneous Protection

The pickup Ii for instantaneous protection cannot be adjusted.

The following table shows the value of the pickup Ii for instantaneous protection (in amperes) according to the trip unit rating In:

The time delay for instantaneous protection cannot be adjusted:

o Non-trip time: 0 ms

o Maximum breaking time: 50 ms.

Setting the Neutral Protection (4P Only)

The neutral selection dial gives a choice of three values for the neutral long-time and short-time protection pickups.

The following table shows the values of the pickup for neutral long-time protection (in multiples of Ir) and neutral short-time protection (in multiples of Isd) according to the dial position:

The time delay for the neutral long-time protection and short-time protection is the same as that for the phases.

Setting the Earth-Leakage Protection

The earth-leakage protection IΔn, type A, is set by using a multi-position dial.

The following table shows the value of the pickup IΔn for earth-leakage protection according to the trip unit rating In:

The OFF setting annuls any earth-leakage protection and the circuit breaker behaves as a standard circuit breaker for cable protection.

Setting the earth-leakage protection to OFF can be used to inhibit earth-leakage protection during periods of setting, commissioning, testing and maintenance.

Setting the Earth-Leakage Protection Time Delay

The time delay of the earth-leakage protection is set by using a multi-position dial.

When IΔn is set to 30 mA, the time delay Δt is always 0 ms regardless of the position of the dial (instantaneous tripping).

When IΔn is set above 30 mA, the time delay Δt can be adjusted to the following values:

o 0 ms

o 60 ms

o 150 ms

o 500 ms

o 1000 ms

Testing the Earth-Leakage Protection

The earth-leakage protection must be tested regularly by using the test button ( T ). Pressing the test button simulates a real leakage current passing through the toroid, and the earth-leakage fault indicator displays the following symbol:

When the earth-leakage protection pickup IΔn is set to the OFF  position, pressing the test button has no effect.

In the case of the Trip version of Micrologic 4, pressing the test button trips the circuit breaker.

In the case of the Alarm version of Micrologic 4, pressing the test button causes the earth-leakage indicator to change to yellow.

If the circuit breaker does not trip, or the earth-leakage indicator does not change to yellow, check that the circuit breaker is energized. If the circuit breaker is energized correctly, and has not tripped or indicated the earth-leakage fault, replace the Micrologic 4 trip unit.

Resetting the Circuit Breaker After an Earth-leakage Fault Trip

Resetting the circuit breaker after an earth-leakage fault trip depends on the version:

o For the Trip version, reset the circuit breaker by moving the handle from Trip  to O (OFF)  position, and then to I (ON) position.

o For the Alarm version, press the test button ( T ) for three seconds.

For Trip and Alarm versions, the earth-leakage fault indicator changes back to gray after the reset.

Examples of Setting the Long-Time Protection

Example 1: Setting the long-time protection pickup Ir to 140 A on a Micrologic 4.2 trip unit rated In 250 A:

Example 2: Setting the long-time protection pickup Ir to 133 A on a Micrologic 4.2 trip unit rated In 250 A:

The actions in steps (2) and (3) on the adjustment dials modify the trip curves as shown:

Example of Setting the Short-Time Protection

Setting the short-time protection pickup Isd to 400 A on a Micrologic 4.2 rated In 250 A on a 133 A feed:

The action in step (2) on the adjustment dial modifies the trip curve as shown:

Example of Setting the Earth-Leakage Protection

Setting the earth-leakage protection pickup IΔn to 1 A with a tripping time delay of 500 ms on a Micrologic 4.2 rated In 250 A:

DOCA0140EN-01

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Evolution of the molded case circuit breaker trip units and their value to customers.

Even though an 1879 patent filed by Thomas Edison provided a glimpse of the definition of what would become circuit breakers, fuses (use once and throw away) were the standard for the first 30-40 years in power distribution systems.1 In 1924, German inventor Hugo Stotz created and patented what was marketed as a re-settable fuse (Figure 1). It was a direct retrofit into common fuse panels of the day. The Stotz fuse incorporated a thermal element to detect and open contacts to clear overloaded or shorted circuits.2 This was a forerunner of the thermal-magnetic breaker (Figure 2) widely used in today’s power distribution systems.

How have circuit breakers evolved since the Stotz? More importantly, how can you take advantage of new circuit breaker technology to deliver to your clients a better tailored and user-friendly project? This brief article will focus specifically on the evolution of the breaker trip unit and the value this evolution provides to customers.

Circuit Breaker and Trip Unit

In order to understand what a trip unit is, let’s revisit the definition of a circuit breaker. A circuit breaker is a mechanical switching device designed to automatically detect and eliminate short circuits and overload current. A trip unit, specifically, is the “brain” of the circuit breaker as its function is to measure physical parameters such as electrical current and decide when to “trip” or rapidly open the mechanical contacts of the circuit breaker. At the bare minimum, a trip unit needs to offer overload and short circuit protection. In regard to the topic of evolution, the trip unit can be as simple as a bi-metallic strip, or now, as advanced as a computer. This evolution has opened the door to so much more than overload and short circuit protection – it’s opened a whole new world of protection, measurement, and control.

Let’s take a look at the evolution of the circuit breaker trip unit in four stages, starting with the basic thermal magnetic circuit trip unit, which is still the most widely used trip mechanism today.

Thermal Magnetic Circuit Trip Unit

The basic thermal magnetic circuit trip unit still provides a cost-effective solution for basic circuit protection and remains in widespread use. With the growth of critical electrical loads, the need for accurate and coordinated circuit protection has become much more important. However, the lower accuracy sensitivity offered by a thermal magnetic breaker cannot fully address this increasing demand. These shortcomings are amplified when you need breakers to trip in a coordinated fashion where only the problematic circuit is taken out of service. This is called selectivity and was a primary driver in the evolution from the thermal magnetic trip unit to the electronic trip unit which can provide a much higher degree of accuracy in sensing and responding to trip events.

Figure 3 exemplifies the typical response of a thermal magnetic breaker in the form of a time current curve (TCC). The X axis represents current and Y axis represents time, in seconds. The grid is logarithmic on both the X and Y axis. The breaker has two elements – ‘L’ or long time for the thermal, and ‘I’ for the magnetic. Note the width of the long-time element indicates a substantial lack of accuracy. Also note that the breaker’s response is significantly affected by temperature. There are two long time curve sections shown. The blue section is the ‘cold’ response and the orange section is the ‘hot’ response. The lack of accuracy makes coordination between thermal magnetic breakers difficult.

First Generation Electronic Trip Units

As noted earlier, this lack of accuracy, along with the growing need for coordinated circuit protection, drove the development of the electronic trip unit. First generation electronic trip units (Figure 4) were simple analog circuits comprised of resistors, capacitors, inductors, and transistors, however, they offered increased accuracy over their thermal magnetic cousins. Electronic trip breakers could be reasonably coordinated and be used to build a selectively coordinated distribution system.

Over the years, electronic trip units underwent incremental improvements including:

• Limited Adjustability – Provided ability to make basic adjustments to instantaneous and overload response to improve selectivity
• True RMS Sensing – Improved accuracy, bringing measurement much closer to the thermal response (not just looking at peak) of the current
• Thermal Memory – Ensured (even lacking the inherent “heater” present in original thermal magnetic breakers) that trip data could be retained and remembered for reporting
• Overall Improvement in Equipment Protection – Due to these enhancements which allowed more selectivity and eliminated the nuisance of premature trips which can damage the equipment

Modern Microprocessor Trip Units

As these electronic trip units continued to evolve, manufacturers used more and more sophisticated and integrated circuits which slowly evolved trip units into the modern microprocessor trip unit. The microprocessor trip unit provides even more improved protection accuracy and adjustability (ability to coordinate breakers closer together thus allowing additional breakers to operate in series IE levels of protection). Electronic trip unit breakers are commonly referred to as ‘LSI’ or ‘LSIG’ where ‘L’ is the long-time trip (60-600 sec), ‘S’ is the short time trip (0.1 to 60 sec), and ‘I’ is the instantaneous trip. ‘G’ is the optional ground fault trip. The ‘L’ and ‘S’ functions replace the thermal element in the thermal magnetic circuit breaker and the ‘I’ replaces the magnetic element. Figures 5 and 6 show the difference in response and adjustability between thermal magnetic and LSIG circuit breakers.

Figure 7 shows the time current curve of a typical breaker with a microprocessor LSI trip unit. Note the increased accuracy and adjustability in comparison with the thermal magnetic breaker.

This improved accuracy and adjustability of LSI breakers allowed for more advanced coordination of increasing layers of panels/circuit breakers in series.

Application Example

A building with a 2000A main switchboard and multiple power panels scattered throughout. Thermal magnetic breakers may allow up to three levels of coordination – switchboard main to switchboard feeder to power panel branch. Suppose the power panels were then feeding lighting panels. The lighting panel branch circuits can not be coordinated as it is the fourth level of coordination. If LSI breakers were used, the same system could be coordinated through the lighting panel and possibly with an additional panel in between (5 levels).

These evolving microprocessor trip units also provide much improved coordination with different types of protective devices such as motor starters, fuses, and relays, as well as the key ZSI (Zone Selective Interlocking) ability which allows planned overlap to gain maximum protection.

One big weakness that had yet to evolve was the advancement of sensors. So, while these electronic microprocessor trip units along with the right add-on equipment could provide early versions of metering from the circuit itself, the data was very inaccurate.

Today’s Advanced Next Generation Microprocessor Trip Units

Finally, we come to today’s advanced microprocessor trip units which are still microprocessor based, but because of the continued miniaturization in electronics to provide additional power, memory, and storage, and with a big change in sensor technology, these new breakers are a quantum leap ahead of their predecessors.

With the evolution of breaker trip units starting with basic overcurrent protection, you now have advanced capabilities that offer a host of additional protective functions nearly equal to functions offered by medium/high voltage multi-function relays. A few key features to look for include monitoring capabilities such as voltage, power quality, and even temperature of external sensors connected to the breaker.

Much of the new functionality is made possible by the replacement of the lower accuracy non-linear iron core current transformers with highly accurate linear current sensors. These sensors are based on the Rogowski coil concept. With traditional iron core current transformers, there is a tradeoff between measurement range and accuracy. Circuit breakers require sensing a large range of currents and accuracy is not as important. Today’s demands for metering require a smaller sensing range and much greater accuracy. The Rogowski coil sensor can cover a wide range of currents and has a very linear response. It is the perfect sensor for both protection and metering.

As mentioned, the real leap in value is moving so many functions “on board” the breaker trip unit that, in the past, could only be delivered by purchasing, integrating, and programming separate devices. A few examples (many more to explore) include:

• Built in programmable logic – Moves functions formerly available only through the addition of one or more PLCs, such as automatic source transfer, load shedding, load control, and generator control
• Communications – Standard network connections, additional communications technology such as IEC6185/GOOSE to high-speed breaker to breaker communications and coordination, including serving as a bridge between LV/MV applications.
• Metering – Ability to delivery revenue-class metering (typically 1% accuracy), harmonic measurement and reporting, and power quality monitoring
• Commissioning – Allows direct access to trip units via HMI panel (one panel for multiple breakers), or USB device (just copy over the settings), or even Bluetooth connection (outside the arc-flash zone)

The Evolution Will Certainly Continue

We’ve touched on the evolution of the circuit breaker trip unit across a century. Generally, three key technical advancements have opened up the possibilities of today’s advanced circuit protection with a molded case breaker – increased processor power (intelligence) due to advances in circuit board/component miniaturization, increased sensor accuracy as advances allowed for the application of the Rogowski coil for linear measurement, and the continued improvements to high-speed communications both in the processor capabilities and communication protocols. Overall, these three things combine to deliver the key cornerstone values required in smarter, safer, and more reliable power – accuracy plus the ability to make decisions and execute responses in milliseconds.

These capabilities will continue to evolve, and you and your customers will continue to benefit from the advancement of cheaper and more available raw computing power and communications over time.

• Friedel, R., & Israel, P. (1987). Edison’s electric light biography of an invention. New Brunswick, NJ, NJ: Rutgers Univ. Pr.
• Riemensperger, S. (2014, October 31). Miniature Breakers Stop Overloads, Short Circuits. Retrieved July 22, 2020, from com/conversations
• Electrical installation handbook – Protection, control and electrical devices (Sixth ed., ABB Technical Guide). (2010). Bergamo Italy: ABB SACE.
• Figure 3 – 3. (n.d.). In A Working Manual on Molded Case Circuit Breakers (Third ed.). Beaver, PA: Westinghouse Electric Corporation

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Record Plus

A New Standard in Molded Case Circuit Breaker Performance Record Plus* molded case circuit breakers offer a new standard of performance: Available up to 600A with interruption capacities up to 200kAIC, global approvals, compact size, dual AC/DC ratings, common internal accessories and a broad range of improved external accessories.

FB100 - Thermal Magnetic Trip The FB100 molded case circuit breakers have the same features as the FC100 circuit breakers with 1 3/8" pole spacing for easy integration into equipment.

Features and benefits

• High interrupt ratings for the expanding available short circuit currents associated with networked transformers.
• Thermal magnetic and electronic trip for broad applications
• Adjustable dial to set Amp rating on PremEon S trip unit
• Large range of rating plug sizes for SMR2 trip units to provide design flexibility
• Compact size for easy integration into switchboard and power panels
• Consistent white finish across the range
• Complete set of field-installable accessories
• Tested to exceed UL requirements of 8000 operations
• Meets UL/cUL 489, IEC 947-2 and is CE Marked - a Truly Global Breaker  

Record Plus Life Cycle Management Classic Phase

FC100 - Thermal Magnetic Trip This 100A breaker has exceptionally high ratings (150kA @ 480V) in a small compact 3" wide frame. This is a breakthrough product that will enable smaller, more efficient designs for our customers.

FG600 - Electronic Trip This 600A breaker offers the highest short circuit ratings in the industry at up to 200kAIC @ 480V, all in a traditional 400A frame.

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• Time Current Curves

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Spectra RMS™ Electronic Trip

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Catalog No. : SELA36AT0060

Description:  SEL 3P 600V 60A

UPC: 783164211467

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Specifications

• Publications

Descriptors

Classifications, se (60af 35/40/45/50rp); long/tracking short time instantaneous.

Publication No.: K215-167C

Publication Type: Time Current Curves

SE (60AF); Let-Through Energy

Publication No.: K215-203A

SE (60AF 60RP); Long/Tracking Short Time Instantaneous

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Publication No.: K215-202A

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• Supplemental and Obsolescence Digest 178

Section 7: Miniature and Molded Case Circuit Breakers

• Miniature Circuit Breakers
• Molded Case Circuit Breakers
• Insulated Case Circuit Breakers
• QO Plug-On Circuit Breakers
• Accessories
• QO™ Mounting Bases
• QOU Miniature Circuit Breakers / QYU Supplementary Protectors
• QOU Accessories
• Plug-On Circuit Breakers
• C60 BP and C60 BPR Circuit Breakers
• C60 SP Circuit Breakers
• C60 H-DC Circuit Breakers
• GFP Ground Fault Protectors
• Multi 9 Circuit Breakers Busbar Offer
• C60 Accessories
• PowerPact Family
• B-Frame Circuit Breakers
• H- and J-Frame Circuit Breakers
• Q/LA/LH/Q4-Frame
• PowerPact L-Frame Electronic-Trip Circuit Breakers
• M-Frame Circuit Breakers
• P-Frame Circuit Breakers
• R-Frame Circuit Breakers
• Selective Coordination
• UL Listed 500 Vdc Circuit Breakers
• PowerPact Automatic Switches
• Instantaneous Trip Circuit Breakers
• Motor Circuit Protectors and Motor Protector Circuit Breakers
• H-, J-, and LA-Frame MCP Selection
• Electrical Accessories
• Motor Operators and Rotary Handles
• Locks, Installation Accessories, and Rear Connections
• Mechanical Lugs
• Compression Lugs and Power Distribution Connectors (PDC)
• Terminal Nuts, Terminal Pads, Terminal Shields and Accessories
• Plug-In and Drawout Mountings

PowerPact H-, J-, and L-Frame Trip Units

• PowerPact P- and R-Frame Trip Units
• MicroLogic™ Trip Unit Accessories
• MasterPact™ MTZ Circuit Breakers
• MasterPact™ NT/NW Circuit Breakers
• Enerlin’X System
• Multi-Product Architecture Examples
• Add-On Ground-Fault and Earth-Leakage Modules
• Miniature and Molded Case Circuit Breakers
• Enclosure Accessories and Dimensions

Class 611 / Refer to Catalog 0611CT1001

Micrologic trip units [1].

MicroLogic Standard 3.2/3.3 Trip Units

PowerPacT™ H-, J-, and L-frame molded case circuit breakers may be specified with any of the following MicroLogic Electronic Trip Units.

True RMS sensing

LI, LSI trip configurations

Field-interchangeable trip units

LED long-time pickup and trip indication

Test kits available

Thermal imaging

MicroLogic Ammeter 5.2A/5.3A/6.2A/6.3A Trip Units

Includes all features listed for MicroLogic standard trip unit, as well as:

Advanced user interface

Neutral protection

Incremental fine tuning of settings

Up to 12 alarms

Digital ammeter—phase and neutral (4-pole only)

Phase loading bar graph

Maintenance indicators including contact wear, number of operations, operating hours, and load profiles

Cause of trip information for troubleshooting assistance

LCD Display

Zone-selective interlocking (ZSI) (short-time & ground-fault)

Optional Modbus™ communications—PowerLogic™ compatible

MicroLogic Energy 5.2E/5.3E/6.2E/6.3E Trip Units

Includes all features listed for MicroLogic ammeter trip unit, as well as:

Ground-fault trip with programmable ground fault alarm (available on 6.2E/6.3E only)

Power and energy measurement

Power quality measurements

Current demand and power demand measurements

PowerPact H, J and L-Frame MicroLogic Trip Units

Micrologic trip unit settings for h-, j-, and l-frame.

• See Supplemental Digest Section 3 for circuit breakers with field-interchangeable trip units.

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Understanding Trip Circuit: Breakers, Overloads, and Solutions for Short Circuits

Understanding circuit breakers and how to deal with constant tripping.

When the circuit breaker in your home trips, it’s important to reset it in the fusebox to restore power. This may require a trip under the stairs or down to the garage, depending on where your circuit breaker is located. Circuit breakers are designed to interrupt the electrical current when the switch is tripped, ensuring the safety of your electrical system.

While circuit breakers are essential safety devices, constant tripping and repeated resetting can be frustrating. However, if you can identify the cause of the frequent trips, you can take steps to address the issue.

What is a Circuit Breaker?

Every home and business premises have electrical circuits controlled and protected by a switching device located in a consumer unit or fuse panel. Modern systems typically use circuit breakers for control and protection, while older systems might still rely on fuses that blow when overloaded. The main purpose of a circuit breaker is to cut off the flow of electricity to prevent circuits from overheating, which can cause damage and even lead to electrical fires.

How Does a Circuit Breaker Work?

A circuit breaker is a switching device that can be operated manually or automatically. It trips and disconnects the circuit to cut off the electricity supply if there’s an excessive current flow or an overload that the switch can’t handle. The circuit breaker is designed to protect your electrical power system and any devices connected to it.

Why Does a Circuit Breaker Trip?

A circuit breaker will trip when there is an electrical fault that could damage the circuit. This fault typically falls into three categories:

• Overloads: The most common reason for circuit breakers to trip is overloading. This occurs when you draw more electrical power from a circuit than it can handle. For example, running multiple appliances simultaneously or exceeding the circuit’s capacity. When a circuit overheats due to an overload, it puts all connected appliances at risk. The circuit breaker ensures the wires don’t excessively heat up and protects against fire hazards.
• Power Surges: Power surges can also cause circuit breakers to trip. These surges happen when there is a sudden increase in electrical voltage, often caused by lightning strikes or faulty wiring in the electrical system. Circuit breakers act as a defense mechanism against power surges by cutting off the excessive flow of electricity.
• Faulty Components: Another reason for circuit breakers to trip is faulty components within the electrical system. This can include damaged wires, short circuits, or defective appliances. When these faults occur, the circuit breaker detects the problem and interrupts the current flow to prevent damage.

Dealing with Constant Tripping

If your circuit breaker is frequently tripping, it indicates that you are demanding too much power from the circuit. To resolve this issue:

• Redistribute Appliances: Distribute your appliances and devices onto different circuits. Avoid overloading a single circuit by spreading the load across multiple ones. This ensures that each circuit operates within its designed capacity.
• Upgrade Your Electrical System: If your system doesn’t have enough circuits to meet modern demands, consider upgrading your electrical system. This may involve installing additional circuits or replacing outdated wiring and panels. A professional electrician can assess your needs and recommend the best solution.

By understanding how circuit breakers work and taking appropriate measures, you can prevent constant tripping, protect your electrical system, and ensure the safety of your home or business.

Understanding Circuit Breaker Tripping: Short Circuits and Ground Fault Surges

Have you ever experienced a sudden power outage in your home or office? Chances are, it was due to a circuit breaker tripping. Understanding the causes of circuit breaker tripping, such as short circuits and ground fault surges, is crucial for ensuring the safety of your electrical system. Let’s explore these common issues in more detail:

1. Short Circuits

Short circuits are a common reason for circuit breaker tripping and should be taken seriously due to their potential danger. A short circuit occurs when a live wire comes into contact with a neutral wire, resulting in an abnormal electrical connection. This can happen in electrical outlets or due to faulty wiring in appliances or plugs.

When a short circuit occurs, the normal electrical resistance is overridden, causing an excessive flow of current through the circuit. This generates excessive heat, which can lead to fires. If you notice a burning smell or dark discoloration around the circuit breaker, it is an indication of a short circuit.

2. Ground Fault Surges

Similar to short circuits, ground fault surges involve a live wire touching a bare copper ground wire or a part of a metal outlet box connected to the ground wire. When this happens, an excess flow of electricity occurs, triggering the circuit breaker to trip. Discoloration around the outlet is also a visible sign of a ground fault surge.

Both short circuits and ground fault surges are not only inconvenient but also pose serious risks to your safety. If your circuit breakers frequently trip, it is crucial to seek professional assistance to identify and resolve the underlying electrical issues. Attempting to solve electrical problems on your own can lead to further complications and put your premises at risk.

Remember, the safety of your electrical system should be entrusted to trained professionals. Don’t hesitate to call for professional help to ensure the proper functioning and safety of your electrical circuits.

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