4/1/201412013 Eaton. All rights reserved.Overcurrent Protective Device (OCPD) BasicsDan NeeserField Application EngineerEatons Bussmann BusinessCell:314-753-2514email: dan.neeser@cooperindustries.com2 2013 Eaton. All rights reserved.Agenda Overcurrent Considerations Overcurrents Overloads Short-circuits &ground faults Component protection Arc Flash Overcurrent Protective Basics Basics Construction, Operation and Ratings (V, A, IR) Time Current Curves Let-through Curves Overcurrent Protective Device Types Circuit Breakers (MCCB, ICCB, LVPCB, AFCIs, GFCIs) Fuses (Class L, H, R, J , T, CC) High Speed Fuses Supplemental Protectors3 2013 Eaton. All rights reserved.Overcurrent Protective Devices Protect FromOvercurrent (NEC Definition)Any current in excess of the rated current of equipment or the Ampacity of a conductor. It may result from overload, short circuit, or ground fault.FPN: A current in excess of rating may be accommodated by certain equipment and conductors for a given set of conditions. Therefore, the rules for overcurrent protection are specific for particular situations.An Overcurrent Results From Overload, Short Circuit, or Ground Faults4/1/201424 2013 Eaton. All rights reserved.Effects Of Overcurrents Conductor insulation damage Fires Equipment damage Arc Flash Energy5 2013 Eaton. All rights reserved.Overload. (NEC Definition)Operation of equipment in excess of normal, full-load rating, or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating. A fault, such as a short circuit or ground fault, is not an overload.An Overload Is NOT AShort Circuit, or Ground FaultsOvercurrent Protective Devices Protect From6 2013 Eaton. All rights reserved.SourceWithinthenormal pathR RR RRRLoadRVSIOL=VS/ RTLoadROverload - ExampleVoltage (V) =480Load Resistance (R) =2 X 12 =24 ohmsWire Resistance (R) =0.01 ohmsIload= (480) / (0.01 + 24) = 20 Amps4/1/201437 2013 Eaton. All rights reserved.Overcurrent Protective Devices Protect FromShort Circuit Current. Not Defined In NFPA, IEEE or other similar organization documents An overcurrent, typically many times larger than normal operating current Can be an arcing fault or bolted fault Can be between phase(s) and/or phase(s) and ground (ground fault)A Short Circuit Is An Overcurrent But Not An Overload8 2013 Eaton. All rights reserved.SourceOutsidethenormal pathR RR RRRISC=VS/ RTVSLoadROut of thecircuitShort-Circuit - ExampleVoltage (V) =480Load Resistance (R) =12 ohmsWire Resistance (R) =0.01 ohmsIload= (480) / (0.01) = 48,000 Amps9 2013 Eaton. All rights reserved.Typical Short-Circuit Currents Home Receptacle - 200 to 500 amps Home Service - 2,000 to 10,000 amps Bussmann Headquarters - 70,000 amps New York City - 202,000 amps St. Louis, MO - 210,000 Chicago, IL - 215,000 Dallas, TX - 220,000 Tulsa, Oklahoma - 260,000 amps4/1/2014410 2013 Eaton. All rights reserved.Short-Circuit Currents Sources of short-Circuits Utility Generator Motors Decreases due to impedance Conductors, bus, etc. Transformers (size & impedance) Must be calculated11 2013 Eaton. All rights reserved.Eaton Bussmann Short-Circuit Calculator NEW version Apple or Android Apps Web (run from homepage after entering contact info)12 2013 Eaton. All rights reserved.OCPD - Voltage & Ampere Rating Voltage Rating Circuit Breakers - 120, 120/240, 240, 277, 480, 480/277, 600V. Fuses - Typically 250 or 600V (Class J& L 600V) Ampere rating 80% (MCCB-UL 489 and standard fused switch-UL 98) 100% - if CB or fused switch is 100% rated in enclosure Few MCCB & Most ICCB - UL489 LVPCB- UL 1066 Bolted pressure switch - UL 977. 4/1/2014513 2013 Eaton. All rights reserved.OCPD - Interrupting Rating NEC 110.9: Device interrupting rating MUST be equal to or greater than the maximum available fault current. Chapter 1 Video Clips - Interrupting Rating14 2013 Eaton. All rights reserved.OCPD Interrupting Rating Circuit Breakers Interrupting rating varies - 10, 14, 18, 22, 25, 30, 35, 42, 50, 65, 100, 125, 200 kA.Dependent upon voltage and manufacturer. No rejection feature for proper application of voltage or interrupting rating Fuses Minimum interrupting rating of 200,000A (except for Class H & K - 10,000A) at rated voltage.Interrupting rating does not vary with voltage.Many at 300kA. Unique dimensions or rejection features to prevent interchangeability15 2013 Eaton. All rights reserved.OCPD - Current Limitation A current limiting fuse will clear a fault within one half of a cycle. Thermal energy is proportionate to the square of RMScurrent multiplied by the time (Irms2t) Mechanical stresses are proportionate to the square of peakcurrent multiplied by the time (Ip2t)4/1/2014616 2013 Eaton. All rights reserved.OCPD - Current Limitation Conductor protection for fault of 45kA/480V (26kA with conductor) with non-current-limiting device (1 cycle) vs. current-limiting device (>1/2 cycle)17 2013 Eaton. All rights reserved.17Equipment Protection NEC 110.10: Equipment short-circuit current ratings must be adequate for maximum available fault current. Must Assure Protection Conductors/Busway Panelboards/Switchboards Motor Controllers/MCCs Switches/Transfer Switches Industrial Control Panels HVAC Equipment Etc. Current-limiting overcurrent devices can provide increased short-circuit protection of components and high short-circuit current ratings for equipment.18 2013 Eaton. All rights reserved.18Arc Flash Energy People Protection Arc flash Energy Is Dependent On: Distance from arcing fault Arcing fault duration or time to clear Speed of the overcurrent protective device Arcing fault current magnitude Available fault current Current-limitation can reduce4/1/2014719 2013 Eaton. All rights reserved.19Arc Flash Testing - Test 4480V, 22.6kA Short-Circuit Current640A NCL OCPD: 6 cycle Clearing Time20 2013 Eaton. All rights reserved.20Arc Flash Testing - Test 3480V, 22.6kA Short-Circuit Current601A CL Fuse: Less Than 1/2 Cycle Clearing Time21 2013 Eaton. All rights reserved.Circuit Breaker Components Major Components Molded Case Frame Operating Mechanism Contacts Arc Extinguishers Trip Units Tripping Conditions Overload Short-Circuit Ground Fault Arcing Fault4/1/2014822 2013 Eaton. All rights reserved.Circuit Breaker Components23 2013 Eaton. All rights reserved.Circuit Breaker Components Contact Assemblies24 2013 Eaton. All rights reserved.Circuit Breaker Components Arc Extinguisher Contacts Separate Magnetic Field Drives Arc Into Steel Plates Arc Is Confined Divided Extinguished4/1/2014925 2013 Eaton. All rights reserved.Thermal Protection Bimetal In Series With Connected Cable Bimetallic Element Is Heated By The Load Current Sustained Overload Will Cause Bimetal To Deflect Deflection Trips The Breaker26 2013 Eaton. All rights reserved.Magnetic Protection Electromagnet Winding Is In Series With Load CurrentCoilN SMagneticField27 2013 Eaton. All rights reserved.Thermal Magnetic Time Current Characteristic Curve4/1/20141028 2013 Eaton. All rights reserved.Different Types And Sizes Molded Case Circuit Breaker (MCCB)A circuit breaker that is assembled as an integral unit in a supporting and enclosing housing of insulating material. Insulated Case Circuit Breaker (ICCB)A circuit breaker that is assembled as an integral unit in a supporting and enclosing housing of insulating material and with a stored energy mechanism. Low Voltage Power Circuit Breaker (LVPCB)A mechanical switching device, capable of making, carrying, and breaking currents under normal circuit conditions and making and carrying for a specified time and breaking currents under specified abnormal circuit conditions such as those of short circuit. Rated 1000 V ac or below, or 300 V dc and below, but not including molded-case circuit breakers.29 2013 Eaton. All rights reserved.Molded Case Circuit BreakersMiniature G Frame E Frame F Frame JFrame K Frame L Frame M Frame N Frame R Frame15 100A 15 100A 15 125A 10 225A 70 250A 70 400A 70 600A 300 800A 320 1200A 800 2500A Continuous Ampere Ratings from 15A to 2500A Frame Interrupting Capabilities of 22KA to 100KA Found In enclosures, panelboards, switchboards, MCCs and Control Panels Industrial AND Residential Applications30 2013 Eaton. All rights reserved.Insulated Case Circuit Breakers Typically 800A 6000A Frame Range Interrupting Duty 35 150kA Found In Enclosures, Switchboards and Switchgear4/1/20141131 2013 Eaton. All rights reserved.Low Voltage Power Circuit Breakers Interrupting Duty from 42kA to 100kA and Current-Limiting Up To 200kA 800A to 6000A Frame Found in Enclosures, Switchboards, and Switchgear Draw-out & maintenance capabilities32 2013 Eaton. All rights reserved.Electronic Trip UnitsCircuit BoardTrip UnitFlux Transfer Shunt TripCurrent Transformer 33 2013 Eaton. All rights reserved.Time-Current CharacteristicDepicts the time required for an overcurrent protective device to open automatically Three Regions Long-time: Opening in minutes Short-time: Opening in seconds or tenths of seconds. Instantaneous: Opening with no intentional delay - millisecondsLong TimePickupLong TimeDelayShort TimePickupShort Time Delay(I2t)InstantaneousPickup0.5 1 10 1000.010.11.0101001000Multiples of Rated CurrentTime In Seconds4/1/20141234 2013 Eaton. All rights reserved.Communications Remote Data Collection Energy / Voltage / Current Cause Of Trip And Other Alarm Information Control HTTPWEBURLInternetHTTPWEBURLInternet35 2013 Eaton. All rights reserved.Zone Selective Interlocking Communication Between Breakers Reduces Trip Time When Possible Helps With Arc Flash Energy ReductionCase 1: Both Breakers See Fault UpstreamBreaker Waits As DesignedCase 2:Only UpstreamBreaker Sees Fault No Input FromDownstreamBreaker Trip As Fast As PossibleIsc36 2013 Eaton. All rights reserved.Arc Flash Reduction Switch ALWAYS WORK DE-ENERGIZED Manually or Automatically enables analog instantaneous pickup Protects all downstream equipment / personnel Limits energy available during maintenance4/1/20141337 2013 Eaton. All rights reserved.Arc Flash Reduction Switch Clearing times are much faster than ZSI Clearing times are faster than standard INSTRef:Incident energy calculated using IEEE STD 1584TM-2002 method for a 480 Vac system, working distance of 24 inches,Grounding type = solid grounded and Equipment type = Switchgear.38 2013 Eaton. All rights reserved.Arc Detection / Fire Prevention Technology Has Progressed To Enable Enhancement Of The Residential MCCB Residential And Commercial Applications39 2013 Eaton. All rights reserved.Arc Detection / Fire PreventionStationary Contact MemberMechanism SpringLatchPieceMoving Contact MemberOperating HandlePush To Trip Test ButtonInstantaneous Trip Element( Armature )Long Delay Trip Element( Bimetal )Electromagnet Load Neutral TerminalPanel Neutral WireLoad TerminalArc Fault Sensing Circuitry4/1/20141440 2013 Eaton. All rights reserved.Dual Element Time Delay Fuses Dual Element Time-Delay MODERN CL FUSES Designed to be sized close to load and accommodate motor and transformer inrush which could not be accomplished by single-element non-time-delay or fast-acting fuses. Overload (time delay) Element Short Circuit (current limitation) ElementShortcircuit elementOverload Element41 2013 Eaton. All rights reserved.Dual Element Time Delay Fuse - OverloadBeforeAfter Dual Element Time-Delay Under sustained overload condition, spring operated trigger assembly separates the connectorfrom the short-circuit element, opening the circuit.42 2013 Eaton. All rights reserved.Dual Element Time Delay Fuses Short Circuit Dual Element Time-Delay Under a short-circuit condition, restricted portions of the short-circuit element melt (vaporize) and arc to burn back the resulting gaps until the arcs are suppressed by the arc quenching material and increased arc resistance.4/1/20141543 2013 Eaton. All rights reserved.Fuse ClassesHigh Speed FusesPermitted to provide short-circuit, ground-fault protection for motor branch circuits utilizing power electronic drives44 2013 Eaton. All rights reserved.Fuse Class Dimensions4445 2013 Eaton. All rights reserved.Time Current Characteristic (TCC) CurvesThe Trip Curve A Trip Curve Is Plotted Time Vs. Current The Curve Tells The Trip Times For Various Levels Of Current Minimum melt, average melt total clear Fast acting fuses faster in overload region than time-delay fuses.Similar in short-circuit region.0.520 200 10000.010.11.0101001000Current (Amps)Time (Seconds)MinimumMeltTotalClearAFuse OpensAt Some TimeBetween These BandsUnderstanding How An Overcurrent Protective Device Operates Is ImportantCurrent LimitingThresholdAverageMeltOverloadShort Circuit4/1/20141646 2013 Eaton. All rights reserved.Fuse Class Current Limitation All manufacturers must comply with maximum let-through values (Peak/I2t) for each fuse class(at fault currents of 50, 100, 200, 300kA)47 2013 Eaton. All rights reserved.Current Limiting Effect Charts Manufacturer (fuse or circuit breaker) published data provides actual Ip and Irms let-through48 2013 Eaton. All rights reserved.Class L Large Class L Low-Peak KRP-C-(AMP)SP 600V, 601A 6000A, 300kA Characteristics Time Delay Current limiting Applications Mains and feeders in electrical distribution equipment Large motors4/1/20141749 2013 Eaton. All rights reserved.Class T Tiny Fast-acting 300V AC or 600V AC Up to 1200A Amperage case sizes include: 30, 60, 100, 200, 400, 600, 800, 1200 200kA Interrupting rating Current limiting Rejection feature class or size rejecting Best space saving design of any power fuse Applications: Heating and lighting circuits Single phase lighting circuits (277V) Residential and multi-metering50 2013 Eaton. All rights reserved.Class H HazardousClass H One-Time NON-(AMP)/NOS-(AMP) 250V/600V, 1/8A-600A 60A or Less 50kA, above 60A - 10kACharacteristicsNon-Time DelayNon-current-limiting & non-rejectingRecommend REPLACE with RK5/RK1Applications General purpose HVAC, light commercial51 2013 Eaton. All rights reserved.Class RK5 Rejection Class RK5 Fusetron FRN-R-(AMP) / FRS-R-(AMP) 250V/600V, 1/10A 600A, 200kA Characteristics Dual Element Time Delay Good current limitation Optional Open Fuse Indication Applications Feeders and branch circuits in electrical distribution and OEM equipment Time delay good for across the line start motor applications and transformer primaries4/1/20141852 2013 Eaton. All rights reserved.Class RK1 Rejection Class RK1 Low-Peak LPN-RK-(AMP)SP/LPS-RK-(AMP)SP 250V/600V, 1/10A 600A, 300kA Characteristics Dual Element Time Delay Better current limitation (better Type2 and Arc Flash protection) Less time delay than RK5 Optional open fuse indication Applications Feeders and branch circuits Primarily Building Systems Electrical Safety Upgrade53 2013 Eaton. All rights reserved.Class J J unior Class J Low-Peak LPJ -(AMP)SP 600V, 1A 600A, 300kA Characteristics Dual Element Time Delay Better time delay than CC Less time delay than RK1/RK5 Very current limiting Smaller than RK1/RK5 Open fuse indication Optional Applications Feeder and branch circuits OEM & Building Systems Type 2 Protection54 2013 Eaton. All rights reserved.Class J J unior Class J DFJHigh Speed Fuse DFJ -(AMP) 600V, 1A 600A, 200kA 450Vdc, 100kA Characteristics High speed performance: extremely current limiting (similar to high speed fuses) Applications Drive branch circuits Heater circuits with solid state relays (SSRs) Protect power electronics and provide branch circuit protection Fit HSF performance into standard, off the shelf, switches, holders and blocks4/1/20141955 2013 Eaton. All rights reserved.Class CF CUBE FUSE Class CF - TCF(amp), TCF(amp)RN or FCF(amp)RN TCF - 600Vac/300Vdc, 1-100A, 300kA/100kA FCF - 600Vac/dc, 1-100A 200kA/50kA Characteristics DE Time Delay or Fast Acting Class JPerformance Very Current Limiting Small physical Size Finger safe IP20 Optional Indicating version time-delay only Applications General purpose; e.g. motor circuits (Type 2 Protection, transformers, heaters, feeders and branch circuit protection WCF_RN CUBEFuse for 690Vac wind turbine systems(UL 248 Recognized) .56 2013 Eaton. All rights reserved.Class CC Control Circuitor Charlie Chaplin(little hat) Class CC - General Features 600V, up to 30A 200kA Interrupting rating Very Current Limiting Space Saving Design - 13/32X 1 Grooved ferrule provides rejection feature from supplementary fuses with same dimensions (midget fuses) when Class CC fuseholders are used Offer 3 different fuse types Time delay (for motor circuit: LP-CC) Time delay (for control transformer primary: FNQ-R) Non-time delay (Non-inductive loads: KTK-R)57 2013 Eaton. All rights reserved.Class G Fuses Growing Time-delay 600V AC, up to 20A 480V AC, 25-60A Amperage case sizes include: 15, 20, 30, 60 100kA Interrupting rating Current limiting Rejecting feature Length of fuse varies with the amperage Applications: Small Motors Small Transformers General applications with inrush current4/1/20142058 2013 Eaton. All rights reserved.Edison-Base Fuses and Fuseholders NEC 240.51(B) permits the use of plug fuses of the Edison-base type to be used only for replacements in existing installations where there is no evidence of overfusing NEC 240.53(A) Classifies Type S fuses as: Not over 125V 0-15A, 16-20A, and 21-30A NEC 240.53(B) Type S fuses cannot be interchangeable with a lower ampere classification Type S fuses are required to be designed for use in only a Type S fuseholder or an Edison-based fuseholder with a Type S adapter inserted. 59 2013 Eaton. All rights reserved.Circuit Breaker versus Fuse Circuit Breakers Size & Flexibility (IR) Resettability(OL) Shunt/Common Trip Integral Ground Fault Protection (multi-level) Adjustable Trip Settings Advanced Protection & Monitoring Features Arc Flash (above 800A and lower fault currents) Switching Operations and Drawout Capability for Maintenance Fuses Reliability limited maintenance Ease of application (V&IR), rejection features Current-limitation Component Protection (motor circuits, high SCCR and protection of solid-state equipment) Arc Flash Protection (typically 800A and less and higher fault currents) Ease of Selective Coordination (use of fuse ampacityratios)2013 Eaton. All rights reserved.Questions And CommentsThank You