GlobalSpec has asked its users about the latest design trends and features related to Circuit Breakers. They have also shared their product applications and tips on how to buy and use these products.
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Q:
What are some of the applications you have used a circuit breaker for?
132 answers
Answers:
I finally started construction work in 1951, switched a couple of contractor and was involved with all Brands and all types of Cir. Breakers, in commercial Buildings, Power plants, Reactors, Dorms, Hospitals, Factories, Stadiums, Switch yards, and you name it. I had a good enjoyable life in the Electrical Construction field.
~William (Bill) Lang, Project mnanager from 1954 on till retirement, Boonville, MO
I run coordination studies for power plants / industrial customers. Not only to properly coordinate a system, but also to mitigate HRC levels. Many times I must recommend replacing breakers to properly coordinate so some design aspects are used. I am also involved in testing breakers, usually on shutdowns by the customer.
~Engineering, Other, Ashland, MA
1.Now I am working as a design engineer and I use MCBs, MCCBs & ACBs in LV panels. 2.When I worked in VCB manufacturing plant, I involved in testing of VCBs 3.When I worked as a Substation Commissioning engineer, EHT CBs were used.
~Sreejith V, Design Engineer, Kannur, India
For all types of protection on MCC up to 5.7 MVA distribution system protection on 80 MVA Transformers step down to 230kv to 34.5kv and circuits of step up up to 100 mva from 4,16 to 13.8kv other generator protection on LSIG and ark protection on MV bus section etc.
~Syed Moheed ALi SMA, Design Engineer, Jubail, KSA
I design and build switchgear. Most of the time, the circuit breakers are used as an over current protection device, though sometimes we use Square D breakers as a means to hold open doors that tend to drift closed.
~Colin K, Sales, Design and Production, Houston, TX
Motor overcurrent protection, transformer overcurrent protection, Imaging equipment overcurrent protection, generator overcurrent protection, and as small as branch receptacle circuits and lighting circuits.
~Warren C, Senior Electrical Designer, Columbus, OH
Generator Output Breakers, 230kV and 500kV Generator Station Service Breakers 4kV 3000A, 4kV Feeders 1200A, 4kV Motor Starting Generator Auxiliary 600V Services, 1600A Buses 250V DC Battery Transfer Systems 600V MCC's,
~Engineering, Process/Production, Nanticoke, Canada
Circuit Breakers have been used by me in all my Power Circuits, Main LT Panels and all machine Control panels right from SF6 High end ones in 110 kV Class to 24 V DC ones.
~Kariyalil Radhakrishnan, Engineering Consultant, Conakry, Rep. Of Guinea
We used circuit breakers mainly for drives application for steel bar mill, PCC, MCC. We are entering in to power generation control systems.
~Milind A, General Management, Pune, India
I have tested, maintained, installed, removed, and replaced thousands of breakers in my capacity as an electrical contractor/ maintenance contractor.
~Jody P, Builder/Contractor, San Diego, CA
Generator main, electrical distribution, substation, mining applications, power plant, generally any commercial or industrial application.
~Larry L, Manufacturer, Plant City, FL
Transmission line circuit breakers, generator circuit breakers, station service circuit breakers, distribution panel circuit breakers.
~Jeff G, Engineer, Phoenix, AZ
Protection of circuit. Trafo protection. Capacitor bank protection. Motor protection. Generator protection. Feeder protection etc..
~Technical Support, Singapore
Residential panels, commercial panels, industrial panels that protect plc's and all other forms of control components and machines.
~Corey M, Builder/Contractor, Tionesta, PA
Domestic installations (MCB's, RCBO's) Large commercial/industrial sites (MCCB's) High Voltage switch rooms (SF6 breakers).
~Tom R, Builder/Contractor, Princes Risborough, England
Circuit and equipment protection, RCD CB's for electrical & life safety in domestic, commercial and industrial applications.
~John B, Construction manager, Brisbane, Australia
Higher kw motor starters, isolators, protection devices, power flow utilities for synchronisation and coordination etc...
~Murty Y, Project Manager, Secunderabad, India
Incomer feeder Outgoing feeder Motor feeder Automatic transfer scheme Manual changeover Bus coupler Control supply
~Khalid Al-Zelaibani A, Engineer, Yanbu, Saudi Arabia
Lighting, rect's power panels, heat tracing, MCC starters, main breakers on secondary side of transformers, MCC feeders
~Technical Support/Services, Blair, NE
Mostly power distribution, portable 3 phase power distribution units both with RCCB units, or as an integrated RCBO.
~Steve C, Research & Development, Sydney, Australia
Motor Feeder, Distribution Feeder, Capacitor Bank Switching, Lighting Distribution, Generator Field Supply
~Viral J, Engineer, Jamnagar, India
Power Supply feeding and isolation during abnormal circuit conditions or maintenance of bus or equipments.
~Abhay K, Engineer, Begusarai, India
Sub station installation, Ship main switchboard commissioning, design team with Merlin Gerin ( Fr ).
~Jean Bozonat, Project Manager, St Hubert, Canada
We have many circuit breaker existing in my company working voltage 6,3 kV, and 70 kV and 150 kV
~Iskandar I, Trouble shooter( electrical technician, Indonesia, Palembang
Over Load Protection Short Circuit protection RCCB's for life protection, Switching Isolation
~Engineering, Design, New Delhi, India
Power Distribution from 220 KV to 230 V. From Industrial applications to Residential Distribution.
~Vijay B, Engineering Consultant, Surat, India
Transformers switchgear (230 volt to 22 000 volts) distribution reticulation circuit protection
~Ian M, Engineering Consultant, Durban, South Africa
Motor starters, lighting panels, power panels, and any place over current protection is needed.
~Other, Huntsville, AL
Circuit breakers are used to control the electrical loads such as motors, pumps and lighting.
~Siva Chandran, Design Engineer, Bangalore, India
For circuit protection in my home, and purchased for use in commercial/industrial circuits.
~Engineering, Faculty/Staff/Student, Couva, Trinidad
Load centers. Switchgear up to 15 kv. AC and DC breakers in designed circuits.
~Mike M, Technical Support, Atlanta, GA
Substations, main control panels, motor starters and controls, air circuit breakers.
~Purchasing, Fort Worth, TX
A variety of applications defined by the Process System (Nuclear Power Generation).
~Thomas U., System Engineer, Clarington, Ontario, Canada
Installation in low voltage compartments of 3ph padmount distribution transformers.
~Design Engineer, Waukesha, WI
Motors, Branch Circuits, Main MCC Breakers, Sub feeders, Mini breakers, DC Breakers
~Ted B, Design Engineer, Orlando, FL
Home applications, and like OEM for protection in power factor correction panels.
~Marketing/Sales, Skopje, Macedonia
Perform/write/QA QC short circuit coordination and Arc Flash studies for clients.
~Raymond W, Engineer, Boston, Suffolk
Distribution, Feeders, Branch circuits ,Motors, Generators, life safety, standby
~Project Management, Worcester, MA
Just replaced one in my house that blew, but mostly just through the sales end.
~Purchasing, Charleston, SC
We adapted circuit breakers for special application in switchgear's designs.
~Technical Support/Services, Sherbrooke, Canada
Control panel application for motors, pumps, conveyors, production equipment.
~Bob D, Marketing/Sales, Highland, IA
Breakers were studied as part of relay coordination and arc flash studies.
~Tom M, Engineer, Honolulu, HI
Commercial, industrial, institutional facilities, central utility plants.
~Engineering Consultant, Cincinnati, OH
1) Protection device 2) Maintenance purpose 3) To isolate the fault
~Trupti A, Engineer, Pune, India
HV switchgear, LV switchgear for oil & gas, power plant applications.
~Mohammed Jahir H, Engineering Consultant, Kuala Belait, Brunei
Cable protection in building conception, public power distribution
~Huber Christian, Engineer, Genève, Switzerland
LV power distribution, MV power distribution, HV power transmission.
~Noorudeen K, Engineer, Dubai, UAE
Electrical circuit protection People Protection Fire Protection
~Purchasing, Corroios, Portugal
Substations protection Interior distribution Emergency systems
~Jose S, System Manager, Joint Base Lewis-McChord, WA
Motor protection, circuit protection, component protection, etc.
~Mark P, Engineer, Bloomington, MN
Arc Flash Study and Mitigation, Short Circuit Study, Load Study
~Associate Engineer, Knoxville, TN
To make or open circuit normal condition and abnormal condition.
~Senthilkumar Dhanavelu, ELECTRICIAN, Rasal khaimah, UAE
Aircraft power systems: Telecommunications power supply systems
~Charles W, Retired engineering /sales V.P., San Digo, CA
Circuit Distribution Transformer protection Motor protection
~Engineering, Other, Cheshunt, Great Britain
Overcurrent protection of industrial power and control systems.
~David P, Engineering Consultant, Pickens, SC
MCCs disconnect, lighting, heaters, and general 110vac control
~Electrician, Castle Rock, CO
1) Power Stations 2) Electronic circuits- Automated systems
~Engineering, Faculty/Staff/Student, Richmond, VA
Conducting of load test and on load test for generator set.
~Engineering, Other, Putrajaya, Malaysia
Protection, measuring, monitoring, signaling, communication.
~Mike B., Engineering Consultant, Los Angeles, CA
Main Disconnect Branch Protection Supplemental Protection
~Ken P, Design Engineer, Tampa, FL
Motor circuits, lighting circuits, motor control centers...
~Other, Moss landing, CA
Protecting electronic equipments as Frequency converters.
~Dirk B, Builder/Contractor, Puerto Ordaz, Venezuela
Panel and control cabinets-- lower OCP to rated equipment.
~Technical Support/Services, McCook, IL
Switchboard protection Transformer protection
~Engineering, Other, Kharir, Yemen
Circuit protection on Low Voltage Distribution equipment
~Engineering, Design, Toronto, Canada
Protection of all manner of electrical power circuits.
~Engineering, Design, Ambler, PA
Feeder circuits, motor control and switchgear circuits.
~Lester Morales, Technical Support, Hahnville, LA
Wires protection, load protection. Motors,feeders,etc.
~Other, Mount Airy, MD
All (electrical) applications have circuit breakers.
~Ole S, Engineering Consultant, Sandefjord, Norway
HV and LV switchboards for motors and transformers.
~Project Management, STAVANGER, Norway
Machine tools including heavy shears and punches.
~Trent B, Field Applications Engineer, Ottawa, Canada
LV, MV, HV distribution and transmission purposes.
~Engineer, Kajang, Malaysia
Building lighting and power distribution systems.
~Engineering, Design, Phoenix, AZ
Houses, Commercial Installations & Drilling Rigs
~Marketing/Sales, Edmonton, Canada
Generating sets industry and power distribution.
~Engineering Consultant, Beirut, Lebanon
MV and LV Switchgear, LV MCC, Dist. Panelboards
~Engineering Consultant, Carol Stream, IL
345kV/161kV/69kV/23.9-11.95kV/600 V Switchgear
~HSU Wanpau, Engineering Consultant, Taoyuan/Guanyin, Taiwan,ROC
Manufacturing Switchgears, Panelboards, etc...
~Jaime L, Manufacturer, San Juan, Puerto Rico
Industrial plants and other such utilities.
~Steven E, N FL and S GA Engineering Manager, Jacksonville, FL
Mainly distribution and circuit protection.
~Mike V, Marketing/Sales, Tampa, FL
System protection and coordination studies.
~Engineering, Consulting, Markham, Canada
Residential, Industrial and Commercial uses.
~Engineering, Design, Ayer, MA
Automotive and Heavy vehicle applications.
~Degory H, Senior Project Engineeer, Dallas, TX
Various applications on circuit protection.
~Engineering, Process/production, Washington, DC
Power supplies, timer power cut-off etc...
~Pallavi, Research & Development, Beverly, AL
For electric utility and industrial use.
~Yook YK, Engineer, Seoul, Republic of Korea
HVAC/R house panels electronic controls
~Maintenance/Facilities Management, Debary, FL
Protection of cables, motors, PCBs....
~Mark P., General Management, Sevilla, Spain
Transmission, distribution, flameproof
~Engineering, Consulting, Al Khore, Qatar
Power distribution, motors, lighting
~Purchasing, Altamonte Springs, FL
Power Distribution, Power Utilization
~Bob P, Faculty/Staff, Idaho Falls, ID
Lighting, motors and control circuits
~Energy Engineer, Mount Prospect, IL
Main isolation of the power circuit.
~Engineering, Design, Tangerang, Indonesia
For distribution circuit protection
~Engineering, Other, AL FAISALYA, Saudi Arabia
Electrical Distribution Isolation
~JAYARAM K, Design Engineer, Seremban, Malaysia
Acceptance and maintenance testing.
~Phillip Serna, Project Manager, Hayward, CA
House installation, construction
~Joven D, Engineer, Dubai, United Arab Emirates
Electrical distribution system
~Quality Control/Assurance, New delhi, India
Feeders, distribution, control
~Ralph P, Estimator, Gloucester, VA
Open a circuit. Close circuit.
~Technical Support, Tulsa, OK
In control panel for extruders.
~Technical Support/Services, Lahore, Pakistan
Lighting, pump, motors panels.
~Purchasing, Half Moon Bay, CA
LV Distribution, switchboards
~Quito, Ecuador
Military electric dash board
~Michele Moscati, General Management, Napoli, Italy
Hi pot, time travel, Bil etc.
~Manufacturing, Whitesboro, TX
Mostly on machine protection.
~Engineering, Process/Production, Jeddah, Saudi Arabia
Generator, pumps, lighting
~Engineering, Other, Kitty Hawk, NC
Installed on a generator set.
~Purchasing, LAGOS, Nigeria
Industrial, home, lab use.
~Lou P, Research & Development, Moon Twp., PA
LV switchboard manufacture
~NEIL T, Estimaing Manager, Melbourne, Australia
Marine electrical systems
~Engineering, Consulting, North Vancouver, Canada
Branch circuits and Mains
~Research & Development, Louisville, KY
Pumps and pumping systems
~Engineering, Design, Telford, PA
PLC Panel and MCC panels
~Jeff M, Design Engineer, Findlay, OH
Installation of equipment.
~Elliott E, Process Engineer, Didcot, Engaland
Over current protection
~Engineering, Design, Chula Vista, CA
For lighting and power.
~Engineering, Design, New Johnsonville, TN
Generator control mccs
~Geetu D, Design Engineer, Belle Chase, LA
Telecom power supplies
~Karl L, General Management, Schliersee, Germany
Distribution systems
~Sean M, Engineering, Design, Calgary, Canada
For motor protection
~Engineering, Consulting, TORONTO, Canada
Test Equipment input
~Mark B, Design Engineer, American Fork, UT
Circuit protection.
~Other, Wharton, NJ
Rating, application
~Technical Support/Services, Tvl, India
Substation design
~Engineering, Design, Sarajevo, Bosnia and Herzegovina
Circuit protection
~Gene, Design Engineer, Columbia, MD
DC field breaker
~Engineering, Other, Gillam, Canada
For our plants.
~General Corporate Mgmt, VADODARA, India
Connected load
~Dayananda S, Project Manager, Doha, VI
Control Panels
~Engineer, Waterbury, CT
Motor circuit
~Technical Support/Services, Randleman, NC
Panels
~General Management, Kakira, Uganda

Top
Q:
Please share with us any “non-standard” applications that a circuit breaker has been used for.
28 answers
Answers:
D.U.R.T. Very fast circuit breaker based on Thomson effect technology. This circuit breaker has been made to be installed on low voltage switchboard with a very short circuit withstand, Opening time < 5 millisecond.
~Jean Bozonat, Project Manager, St Hubert, Canada
480 4000 Amp fuses acting as a main protection for multiple lineups of switchgear. The trip curve on the 4000 Amp fuses allowed extensive damage to the LV switchgear when a fault occurred.
~Mike V, Marketing/Sales, Tampa, FL
Emergency Power Off Switch. We use a low voltage release to trip the Main Disconnect when an EPO switch is activated dropping the loop to the low voltage switch.
~Ken P, Design Engineer, Tampa, FL
Medium Voltage Vacuum Circuit Breakers, Small in Size, 600 Amps, For Auto Transfer Switches and Paralleling Switchgear.
~Jaime L, Manufacturer, San Juan, Puerto Rico
I have placed circuit breakers in line with fuses to reduce replacement of fuses because of the high cost of fuses.
~Bob D, Marketing/Sales, Highland, IA
Harmonic analysis up to the 40th harmonic Energy measurement (active, reactive, apparent)
~Mike B., Engineering Consultant, Los Angeles, CA
Remote electrical motorized racking system to connect & disconnect the circuit breakers.
~Technical Support/Services, Sherbrooke, Canada
It is set mounted on an electrical generating set, powered by a reciprocating engine.
~Engineering Consultant, Beirut, Lebanon
Installation in 3ph distribution padmount transformer low voltage compartment.
~Design Engineer, Waukesha, WI
Military test stand project stabs copper plated for offshore application.
~Geetu D, Design Engineer, Belle Chase, LA
There are countless CBE applications, and none are entirely "standard".
~Mark P., General Management, Sevilla, Spain
DC Current, DC make Breaker, 100% Rated Breakers.
~Ted B, Design Engineer, Orlando, FL
Electrically operated switch and motor starter.
~Larry L, Manufacturer, Plant City, FL
1000VDC breaking in Solar applications
~Karl L, General Management, Schliersee, Germany
Arc furnace Electrode boiler
~Ian M, Engineering Consultant, Durban, South Africa
MV breaker as an MV Starter
~Engineering Consultant, Carol Stream, IL
Used as disconnect device.
~Joven D, Engineer, Dubai, United Arab Emirates
Submarine switchboards
~NEIL T, Estimaing Manager, Melbourne, Australia
Motor disconnect means
~Jose S, System Manager, Joint Base Lewis-McChord, WA
Job site paper weight.
~Technical Support, Tulsa, OK
Frequency converter.
~Dirk B, Builder/Contractor, Puerto Ordaz, Venezuela
On staco devices.
~Lou P, Research & Development, Moon Twp., PA
Simple isolators
~Murty Y, Project Manager, Secunderabad, India
Light switch
~Corey M, Builder/Contractor, Tionesta, PA
50 VDC power
~Mark B, Design Engineer, American Fork, UT
Photovoltaic
~Purchasing, Corroios, Portugal
LV motor
~Mohammed Jahir H, Engineering Consultant, Kuala Belait, Brunei
Switch
~Gene, Design Engineer, Columbia, MD

Top
Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of a circuit breaker?
35 answers
Answers:
Incorrect protection levels set on breaker causing motors pump to shutdown, resulting in flooding a motorway tunnel roadway, closing the road.
~John B, Construction manager, Brisbane, Australia
There are hundreds of stories out there, most are caused by Human error. Be sure that a Qualified Individual is installing and energizing your equipment. In other words, don't let somebody's brother in law who "Knows a little bit about electricity" install. Recommend or work on your gear to save a little bit of money. If in doubt, call me at Coastal Power Systems and I or someone else can help you with your needs.
~Colin K, Sales, Design and Production, Houston, TX
Yes. I've seen the result of an owner not replacing a circuit breaker and wire when they have replaced a pump motor with a larger horsepower motor than was originally installed. Cost them more the second time than it would've if they'd done it right the first time of replacement.
~Warren C, Senior Electrical Designer, Columbus, OH
If you don't select the breakers with the correct short circuit rating and settings are not properly set in the trip unit, then it will not trip under abnormal condition. It will damage the electrical load which is connected with it.
~Siva Chandran, Design Engineer, Bangalore, India
Thermal CBEs are sometimes used as protection against short circuit, and the majority of these devices are not fast enough to prevent damage occurring. It is very important to know what you want to protect against and choose your protective devices accordingly.
~Mark P., General Management, Sevilla, Spain
Yes, many OPEX-s (operational experiences) are recorded and shared within the Nuclear Industry which are - I believe - also accessible for the public through the Internet. (Some of these are recorded accidents and their full stories, lessons to be learned...etc...)
~Thomas U., System Engineer, Clarington, Ontario, Canada
Not personally, but potentially serious destruction of life and property could occur if incorrect selections are made. Circuit breakers are there to protect cables and equipment so that their ratings are not exceeded.
~Tom R, Builder/Contractor, Princes Risborough, England
Yes, it was due to human mistake. Metallic tool kept inside the circuit breaker after completing the PM. Breaker was racked-in service position then severe flash over occurred.
~Khalid Al-Zelaibani A, Engineer, Yanbu, Saudi Arabia
During a problem of Breakers not tripping in the proper sequence finally ending up taking our a 480Volt- 2000 amp switchgear unit which started from a 20 amp breaker failure to trip in a secondary panel.
~William (Bill) Lang, Project mnanager from 1954 on till retirement, Boonville, MO
Total switchboard failure when a circuit breaker was reset multiple times after tripping on a bolted short circuit, and eventually failed creating an unlimited arcing fault.
~NEIL T, Estimaing Manager, Melbourne, Australia
Yes, be sure the interrupting capacity of the circuit breaker is not overdutied. Test installed circuit breakers on a regular basis, open, close and trip.
~Larry L, Manufacturer, Plant City, FL
Yes, most of them are related with connecting or disconnecting a close breaker. In all cases there was a mechanical problem with the circuit breaker.
~Technical Support/Services, Sherbrooke, Canada
Two places one with form 2 and 3 kind of design and other with different fault level placements (upsteam and down stream in different kAs).
~Murty Y, Project Manager, Secunderabad, India
Using a 240 Volt rated breaker where a 600 volt rating is required, also using the wrong short circuit rating.
~Jaime L, Manufacturer, San Juan, Puerto Rico
Make sure whether you would need a thru the door/fixed/with-drawable breaker if putting inside the MCC .
~Geetu D, Design Engineer, Belle Chase, LA
Having to replace several breakers because they do not have versatile settings to meet protection needs.
~Phillip Serna, Project Manager, Hayward, CA
Increase of fault current by rapid increase of power source makes existing Circuit Breaker not work.
~Yook YK, Engineer, Seoul, Republic of Korea
Yes . . . when a circuit breaker's design does not satisfy its application requirements.
~Mike B., Engineering Consultant, Los Angeles, CA
So far nothing such thing happened. Improper selection has given faulty alarms on SCADA.
~Syed Moheed ALi SMA, Design Engineer, Jubail, KSA
If short circuit capability of breaker is not sufficient, the breaker will blow.
~Mohammed Jahir H, Engineering Consultant, Kuala Belait, Brunei
It's a protection device. Transformers burn if CB is unable to operate properly.
~Trupti A, Engineer, Pune, India
Many. But most of all problems occur when circuit breakers are not maintained.
~Steven E, N FL and S GA Engineering Manager, Jacksonville, FL
The circuit breaker is damaged if the short circuit rating is inadequate.
~Vijay B, Engineering Consultant, Surat, India
Many - just look at all arc fault related stuff and improper ground stuff.
~Lou P, Research & Development, Moon Twp., PA
If it trips once, try it again. If it trips twice, check your circuit.
~Mike M, Technical Support, Atlanta, GA
Incorrect breaker used, cause failure, Breaker came apart.
~Ted B, Design Engineer, Orlando, FL
Unsuitable CB breaking capacity-caused an explosion.
~Engineer, Kajang, Malaysia
Control Circuit burnt resulting in long down time.
~Kariyalil Radhakrishnan, Engineering Consultant, Conakry, Rep. Of Guinea
Possibly the low trip in certain applications.
~Dirk B, Builder/Contractor, Puerto Ordaz, Venezuela
Person backfed a panel from another panel.
~Corey M, Builder/Contractor, Tionesta, PA
Improper use of terminal lugs, handling
~Joven D, Engineer, Dubai, United Arab Emirates
Selection of voltage type.
~General Management, Kakira, Uganda
Yes SF6 gas CB explosion.
~Jean Bozonat, Project Manager, St Hubert, Canada
Equipment blowing up.
~Steve H, Marketing/Sales, Paducah, KY
Not at this time.
~Jose S, System Manager, Joint Base Lewis-McChord, WA

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