Characteristic curves (time/current characteristic curves) The time/current characteristic curve specifies the virtual time (e.g. The current axis may be expressed in amperes and can be scaled in multiples of 10 while the time axis is usually in the range of 0.01s to 1000s. CLS Fuses - Time Current Curves. A typical fuse time current curve is s… The figures along the bottom (horizontal axis) represent current in amperes. Copyright © All rights reserved. Transformers - JCT-(amp)E, E-Rated for Potential & Sm. 160-630A - Square Body DIN 43 654, 1000V (IEC/U.L.) In general, time-delay fuses hold 500% of the rated current for a minimum of ten seconds, yet will still open quickly on higher values of current. • Select very fast-acting fuses to protect very low withstand components, such as semiconductors. Transformers - JCI-(amp)E, R-Rated for Motor Circuit Protection - JCK/JCK-A, R-Rated for Motor Circuit Protection - JCL/JCL-A, E-Rated for Potential & Sm. Understanding time-current curves and the basic considerations in establishing proper coordination between overcurrent protective devices is very important. To illustrate the use of table 15-3, let us consider the following examples. Figure 1 shows a TCC plot of a fuse and an overcurrent relay. Eaton’s mission is to improve the quality of life and the environment through the use of power management technologies and services. RE: Fuse time current curves cuky2000 (Electrical) 6 Mar 20 04:39 Type N fuses conform to previous NEMA standards and have been superseded by Type K and T links in ratings of 5 through 200A for use in cutouts rated through 27kV. At this value of fault current, the fuse is expected to operate in 0.074s while the overcurrent relay will operate in 5.73s. Figure 1 is a sample time-current curve for the MAXI Fuse series for fuses rated 20-60A. However, when coordination is very difficult, if not impossible, a compromise should be made. : IEEE. In other words, as the current increases, the pre-arcing time decreases. In other words, it always up to you! The greater the current, the smaller is the time taken by the fuse to blow out (or fuse element to melt). Effective overcurrent protection is carried out through an overcurrent coordination study, and with coordination comes the concept of time-current curves. These graphs should be used by the engineer to detrmine the proper fuse size. The list is for current production and out of production GE devices. Time-Current Curves Circuit Breakers 17 . Littelfuse POWR-PRO ® and POWR-GARD time-delay fuses are designed to meet these types of protective needs. continue, fuses must then open before system components are damaged. The area to the right and above the device time-current curve is the ‘operate’ region while the area to the left and below the device time-current curve is the ‘no operate’ region. Table 15-3 recommends a CTI of 0.22 for fuse-to-electromechanical relay coordination. A different CTI is recommended for a different circuit breaker interrupting time. Using the 75% minimum melting time, the minimum melting time of the protected fuse is calculated as follows. A time current curve (TCC) plots the interrupting time of an overcurrent device based on a given current level. It's quite possible that if you would extend the measurements far enough up, you would actually end up below the rated current. The current axis may be expressed in amperes and can be scaled in multiples of 10 while the time axis is usually in the range of 0.01s to 1000s. The average melting time for any current can be determined from the curve. Examples are provided explaining the fuse graphs of a current limiting fuse. The "Time-Current" Fuse Curves indicate how fast a fuse will interrupt the circuit based on a varying amount of current. In our previous discussion, we laid down the concept of zones of protection as well as the objectives of overcurrent coordination. Relay overtravel is basically the inertia of a rotating induction disk in an electromechanical relay. while medium- and high-voltage power fuses can withstand currents below 200% of the their nominal rating. 250-800A - Square Body DIN 43 655, 1000V (IEC/U.L.) Take note of th… The recommended CTIs for coordination of various overcurrent protection devices are listed in IEEE Std 242. Take note of the current axis. This is shown in the following tables. The induction disk starts to rotate from the passing of currents above the configured threshold or pick-up value. Expand All / Collapse All. It is desired that as fault current increases the … Fuses are essentially made up of a metal wire or strip that melts when excessive currents flows through. Centralia, MO. Transformers - JCD-(amp)E, E-Rated for Potential & Sm. CLT Fuses - Time Current Curves. This is the point on the y-axis in which the fault current intersects the device time-current curve. Transformers - JCE-(amp)E, E-Rated for Potential & Sm. Consider for example the figure below, for a fault of 1kA at the protecting fuse, the maximum clearing time is 0.0632s. Overcurrent protection is often the simplest and cheapest to employ but in most cases, its application tends to be difficult. Eaton uses cookies to help us give you the best experience on our website. A time current curve (TCC) plots the interrupting time of an overcurrent device based on a given current level. This curve tells you directly, given a chosen amount of over-current applied to the fuse, how long it will take to fuse in typical conditions. The following illustration shows how a time-current curve works. Boca Raton, FL: CRC Press. The time-current overcurrent capacity of distribution transformers is given in ANSI/IEEE C 57.109 entitled “Guide For Transformer Through-Fault-Current Du-ration.” With the overcurrent time-current capacity of the equipment known, and by the use of time-cur-rent characteristic fuse link curves the proper fuse link can be chosen. The upper portion of the time-current curve shows the circuit breaker’s thermal response, the curved line indicates the nominal performance of the circuit breaker.In thermal magnetic breakers, a thermal overload occurs when a bi-metal conductor inside the circuit breaker deflects after becoming heated by the load current, de-latching the operating mechanism and opening the contacts.The larger the overload, the faster the bi-metalic … The duration from the energization of the circuit breaker trip circuit up to the extinction of arc on the primary arcing contacts is referred to as the ‘interrupting time’. IEEE Std 242-2001 [The Buff Book]: IEEE Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems.(2001). A Time Current Curve (TCC) is a graphical representation of the operating characteristics of overcurrent protection devices at different magnitudes of fault currents. Fast curve gM Very current limiting Voltage 415VAC High breaking capacity : 80kA @ 415VAC tested A type : bracket connection, B type : blade with single central fixing hole connection A and B types - gM curve Ratings A type A1 : 20A A2 : 30A A3 : 63A A4 : 100A and 200A Approval Asta 20 Certified • The fuse complies with standard EN 60269-2 S&C’s Time-Current Characteristic (TCC) Curves are available in Adobe® Acrobat® format as well as in Microsoft® Excel format for your use in other applications. View and download the time-current curves and energy let-through curves. Current values increase from left to right, and time increases from bottom to top. To find out more about the cookies we use and how to control them, please visit our privacy, cookies and data protection page. Enter your email address to subscribe and receive notifications of new posts by email. We provide sustainable solutions that help our customers effectively manage electrical, hydraulic and mechanical power – more safely, more efficiently and more reliably. Trip Curves, aka Time Current Curves, can be an intimidating topic. The following table summarizes the minimum CTIs for most industrial applications. TIME DELAy /CLASS CC FUSES. (2014). This is illustrated in figure 6. Being such, fuses operate on a continuous-ampere rating. Understanding Time-current Curves Time-current curves provide a graphical representation or plot of a fuse’s average melting (opening) time at any current. This removes the initiating energy to the induction disk. Click this link to learn about the parameters that define an overcurrent device time current curve. These curves are provided by the manufacturers of electrical overcurrent interrupting devices, such as fuses and circuit breakers. Table 15-3 recommends a CTI of 0.20 for electromechanical-to-static relay coordination. These CTIs are based on the following considerations: Medium- and high-voltage circuit breakers cannot instantaneously open their contacts after energization of the trip circuit (receiving a trip signal from the relay) due to mechanical limitations. For example, a 3-cycle circuit breaker will operate in 0.05s at 60Hz. Fuse Type Percent of Current Above Amp Rating 200% 500% 1000% Fast/Normal Acting ±20% ±10% ±10% Dual Element/ Time Delay ±25% ±20% ±10% All time-current curves must meet the same basic testing requirements when attempting to duplicate a curve as well as adhering to specific testing conditions relative to each type of curve. Why do we need coordination of overcurrent protection devices? These curves are provided by the manufacturers of electrical overcurrent interrupting devices, such as fuses and circuit breakers. Hubbell Power Systems, Inc. (2000). Low-voltage power fuses can withstand 110% of their rating under controlled conditions. The typical relay overtravel duration is 0.10s. When the downstream protective device successfully operates to isolate the fault, the current through the electromechanical relay drops-out below the threshold or pick up value. Time-current curves for Littelfuse POWR-GARD®.3 fuses can be found online at littelfuse.com/technicalcenter. It can be seen in the TCC plot that the minimum melting time of the protected fuse is 0.0901s for a fault of 1kA. The bottom line is to limit the extent of service interruptions by ensuring that only the devices needed to isolate the fault will operate. So when can we say that overcurrent protection devices are effectively coordinated? While the primary objective of power system protection is to isolate faults as quickly possible, limiting service interruptions to a minimum cannot be discounted. Time-current curves are used to show how fast a breaker will trip at any magnitude of current. For a specific value of fault current, the operating time of the overcurrent device can be determined from its time-current curve. As you can see, these particular fuses are designed to fuse at about 2x their rated currents, and with small over-currents might take as long as 100 s to fuse. Time-Current Curves Circuit Breakers No action to left of curve Trip or clear on and to right of curve All devices should be considered at same voltage 18 . A fuse’s time-current characteristics can help. The figures … CLPT and NCLPT Fuses - Time Current Curves. However, IEEE Std 242 did not specify the CTI between fuses, rather, the standard recommends to consult the device manufacturer. ATDR1/4 to 30 Melting Time – Current Data, 600V Fuses Peak Let-Thru Current Data – ATDR1/4 to 30, 600 Volts AC privacy, cookies and data protection page, Automotive Reset Circuit Protectors - 120 Series, Fast-Acting Automotive Blade Fuses - ATC Series, ATM Automotive Blade-Type Fuses - ATM Series, Maxi Fuse In-Line Fuse Holder - HHX Series, Limitron Class CC, Time-Delay Fuses - FNQ-R, Limitron Fast-Acting Class CC Fuses - KTK-R, Low-Peak Time-Delay Class CC Fuses - LP-CC, Fast-Acting CUBEFuse 600Vac/dc, 1-100A - FCF_RN, Low-Peak Class CF CUBEFuse With and Without Indication - TCF/TCF_RN, Privacy, cookies & data protection policy, General Purpose Size-Rejecting Class G Fuses - SC, Replacement  fuse links for 250V REN and 600V RES renewable fuses in ratings from 1-600 amps - LKN / LKS, General Purpose One-Time 250V Class H & K5 Fuses - NON, General Purpose One-Time 600V Class  H & K5 Fuses - NOS, Renewable 250V REN and 600V RES Fuses in Ratings from 1-60 Amps - REN / RES, Limitron Fast-Acting 600V, Class J Fuses - JKS 1-60A, Limitron Fast-Acting 600V, Class J Fuses - JKS 70-600A, Low-Peak Dual-Element, Time-Delay, Class J Fuses, 0-60 Amp - LPJ 0-60, Low-Peak Dual-Element, Time-Delay Class J Fuses, 70-600 Amps - LPJ 70-600, Low-Peak Time-Delay Class L Fuses - KRP-C 2001-6000, Low-Peak Time-Delay Class L Fuses - KRP-C 601-2000, HI-CAP, Current Limiting 225-600A Class L Fuses - KRP-CL, Limitron Fast-Acting 250V Class R Fuses - KTN-R, Limitron Fast-Acting 600V Class R Fuses - KTS-R, Low-Peak Dual-Element, Time-Delay 250V, Class RK1 Fuses - LPN-RK 1/10-60A, Low-Peak Dual-Element, Time-Delay 250V, Class RK1 Fuses - LPN-RK 70-600A, Low-Peak Dual-Element, Time-Delay 600V, Class RK1 Fuses - LPS-RK 0-60, Low-Peak Dual-Element, Time-Delay 600V, Class RK1 Fuses - LPS-RK 70-600A, Fusetron Dual-Element, Time-Delay 250V - FRN-R (1/10-60A), Fusetron Dual-Element, Time-Delay 250V - FRN-R (70-600A), Fusetron Dual-Element, Time-Delay 600V - FRS-R(1/10-60)A, Fusetron Dual-Element, Time-Delay 600V - FRS-R(65-600)A, Limitron Fast-Acting  300V Class TFuses - JJN, Limitron Fast-Acting 600V Class T Fuses - JJS, 1⁄4 x 1-1⁄4 Fast-Acting Ceramic Tube Fuses - ABC/ABC-V Series, 1/4" x 5/8" Fast-Acting Glass Fuses - Axial lead discontinued - AGA, 1/4" x 1-1/4" Fast-Acting Glass Fuses. In this plot, the current axis is expressed in amperes with a current multiplier of 10 and with a reference voltage of 13.8kV. Blackburn, J. A time current curve (TCC) plots the interrupting time of an overcurrent device based on a given current level. Time-current characteristics are presented graphically on standardized “log-log” paper. Like other protection devices (see biased differential protection), the TCC plot has ‘operate’ and ‘no operate’ regions. In an article on the Application of Primary Fuses by Hubbell Power Systems, Inc., in order to provide a safety margin against operating variables, the maximum clearing time of the downstream fuse should be no greater than 75% of the minimum melting time of the upstream fuse. Protective Relaying Principles and Application, 4th ed. The time required to blow out the fuse depends upon the magnitude of excessive current. In figure 1, the area to the left and below the fuse time-current curve is its ‘no operate’ region. This time interval is referred to as the Coordination Time Interval (CTI). A Time Current Curve (TCC) is a graphical representation of the operating characteristics of overcurrent protection devices at different magnitudes of fault currents. CLE, HLE, and HCL Fuses - Time Current Curves. S&C also offers Coordinaide™ — The S&C Protection and Coordination Assistant. Curve selections were updated for the S&C TripSaver® II Cutout-Mounted Recloser: Added NE and NK Speed under “Definite Time and Fuse Link” selection; Added a 140-A trip-coil rating for McGraw Type L, V4L, and 4E devices; Added “S&C A*” fast curves for McGraw Type 4E, 4H, L and V4L devices Bothe Fuse and Circuit breaker are rated in Amperes (which can be seen on its nameplate) which is known as Rated Current or Nominal Current.We know that both fuse and circuit breaker having the same rated current (say 30A) will not trip when more than 30A (say 32) is flowing through them. However, because of inertia, the induction disk cannot instantaneously stop rotating and may overtravel up to the electromechanical relay operating point. Fuse Time-Current Curves. 25 and 38 kV Type CLPT current limiting fuse trip curve. 8–15 kV Type CLPT current limiting fuse trip curve. Click the +/- accordions below to see the TCC Curves. the melting time) as a function of the prospective current under specific operating conditions. In order to make the curves more readable, the performance Before that, let us answer this first. Time versus Current Curves and Peak Let-Through Current Curves Fuse peak let-through current curves are generally available for UL Class fuses. Cream Magazine by Themebeez, primary objective of power system protection, Explore Overcurrent Coordination using ETAP Software, ETAP Star Coordination on Focus | Detailed Example, Development Of IDMT Relay Curves – PAC Basics, Detailed Example | ETAP Star Coordination On Focus – PAC Basics, Vector Group of Transformer Dyn1|Dyn11|Ynd1|Ynd11, Fault Level Calculation Using The MVA Method, Introduction to Basic Overcurrent Protection and Coordination Study, Relay Overtravel (for electromechanical relays). This graph contains I p curves for top of the class ratings for a time-delay Class J fuse. Fuses Time Current Curves Eaton’s mission is to improve the quality of life and the environment through the use of power management technologies and services. Transformers - JCW-(amp)E, Characteristic Curves for Types RBA and RDB Power Fuses, 1000Vdc 10 x 38mm Photovoltaic Fuse - 1 to 30 Amps - PV, 1000Vdc & 1500Vdc XL Size 01, 1, 2 and 3 Blade and Bolt PV Fuses - PV_XL, 01XL, 1XL, 2XL and 3L Size 1000Vdc Bladed and Bolted Photovoltaic Fuses - PV-(amp rating)A(size)XL & PV-(amp rating)A(size)XL-B, Fast-acting UL Listed 600Vac/dc Solar Fuse - PVS-R, Auto, Manual & Switchable reset - 180 Hi-Amp, 13/32 x 1-1/2" Fast-Acting Glass Fuses - AGU, Fast Acting Ferrule Fuse for Digital Multimeters - DMM-B, Radial Lead Micro Fuse, Fast-acting - EFF, 700V, North American Blade style - FBP-(35-1000)A, Ferrule 6 X 32, 500V, 10-30 A - GBH / GBH-V, 5 x 20mm, Fast-Acting, Ceramic Tube Fuses - GDA/GDA-V Series, 5 x 20mm Fast-Acting Glass Fuse - GDB/GDB-V Series, 5 x 20mm, Time-Delay, Glass Tube Fuses - GDC/GDC-V Series, Fast Acting Specialty Fuses and Fuse Holder - GMW/HWA, Time-Delay Current Limiting Fuses - HAC-R, Limitron Capacitor Indicating Fuse - KGJ, KGJ-E, 13/32" x 1-3/8" Ferrule Type, Fast-Acting Fuses - KTQ, Obsolete - See electronics datasheet 4074 for details - MCR, 1/4 x 11/4" Time DeIay Ceramic Fuse - MWO, Printed Circuit Board Fuses - PC-Tron Series, Subminiature, Time-Delay Fuses - SR-5 Series, 1/4" x 1-1/4" Glass Fuses - TDC10/TDC11 Series, Transient Voltage Surge Suppression Limiters - TVSS, Telpower DC Power Distribution Fuses - TPB, Telpower DC Power Distribution Fuses - TPH. We provide sustainable solutions that help our customers effectively manage electrical, hydraulic and mechanical power – more safely, more efficiently and more reliably. when can we say that overcurrent protection devices are effectively coordinated? By plotting the time-current curves, we can estimate the respective operating time of the overcurrent devices. The goal of this short paper is to introduce you to ... • Circuit protection devices include fuses, miniature circuit breakers, molded case circuit breakers, supplementary protectors, motor protection circuit breakers, overload relays, electronic fuses and air circuit breakers. Note that the circuit breaker interrupting time for the values presented in table 15-3 is 5 cycles, equivalent to 0.08s at 60Hz. From these operating times, we can calculate the time interval between the operation of these devices. For example, Littelfuse’s 383 series - TR5® time-lag 300V rated fuses have time-current characteristics as shown by the below graph. A TCC is a two-dimension plot with the current at the x-axis and the time at the y-axis with both axes are in logarithmic scale. This was taken from Table 15-3 of IEEE Std 242. 50-400A - Square Body DIN 43 653, 1000V (IEC/U.L.) A TCC is a two-dimension plot with the current at the x-axis and the time at the y-axis with both axes are in logarithmic scale. Application of Primary Fuses. The safety margin for relay operating time and the manufacturer’s tolerances and setting errors, fault current magnitudes, CT ratios, and so on. Common circuit breaker interrupting times are: Understand how circuit breaker interrupting time affect the interrupting duties by clicking this link. ATDR. Figure 1 shows a TCC plot of a fuse and an overcurrent relay. These curves are provided by the manufacturers of electrical overcurrent interrupting devices such as fuses and circuit breakers. ABB (ABBN: SIX Swiss Ex) is a leading global technology company that energizes the transformation of society and industry to achieve a more productive, sustainable future. Eaton’s 2019 revenues were $21.4 billion, and we sell products to customers in more than 175 countries. Figure 5 is representative of the format generally followed by fuse manufacturers. AMP-TRAP 2000 ® Time in Seconds Current in Amperes Available Current in RMS Symmetrical Amperes Maximum Instantaneous Peak Let-Thru Amperes. 315-1400A - Square Body DIN 43 656, 1000V (IEC) 160-630A - Square Body Flush End, 1000V (IEC) 250-800A - Square Body Flush End, 1000V (IEC) 315-1400A - Square Body Flush End, 1000V (IEC) 50-400A - Square Body Flush End, >1000V (IEC) 160-630A - Square Body US Style, 1000V (IEC) 315-1400A - Square Body US Style, 1000V (IEC) 50-1400A - Square Body US Style, 1000V (IEC) 50-400A - Square Body US Style, IEC 8x31, 10x38, 14x51 and 22x58 mm Class gG/gL and aM Cylindrical fuses - C08G, c10G, C14G, c22G, C08M, C10M, C14M and C22M, HRCI-CB Industrial Ceramic, Clip-ln - CIF06B, HRCI-CA Industrial Ceramic Bolt-On Fuse - CIF21, 660V, British Standard, BS88 - EET(90-160), BS88:4 690V Pre-arc & Let-through Curves - EET(90-160), HRCI-CB Industrial Ceramic, Clip-ln - EK-B, Coordination BS88: 13.8x 67.5mm offset blade - ESD, 2 to 1250 Amps, NH Sizes 000 - 4, Class gG/gL - NH Fuses - 500Vdc, NH Sizes 000 - 4, Class gG/gL - NH Fuses - 690Vac, HRC Fuselinks - sizes 000 to 4 - NH - HRC Fuselinks, NH DIN Dual Indication Fuse Links - NH DIN Dual Indication Fuse Links, 660V, British Standard: BS88 - RFEE(250-315), expand and collapse Low Voltage Supplementary, Fast-Acting 13/32" x 1-1/2" (10x38mm) Midget Fuses, 250Vac, 2/10-30A - BAF, Fast-Acting 13⁄32 x 1-1⁄2 (10x38mm) Midget Fuses, 600Vac/dc, 1⁄1030A - DCM, 13/32" x 1-1/2" Pin Indicating Type - FNA, 1/4" x 1-1/4" Pin Indicating, Non-Time Delay - GBA, 1/4" x 1-1/4" Pin Indicating, Non-Time Delay - GLD, Fast-Acting Fuse, Rejecting Fuse Holder - GLQ / HLQ, Fast-Acting Fuse, Non-Rejecting Fuse Holder - GLR / HLR, Time Delay Fuse, Non-Rejecting Fuse Holder - GMF / GRF / HLR, Time Delay Fuse, Rejecting Fuseholder - GMQ / HLQ, Fast-Acting 13/32" x 1-1/2" (10x38mm) Midget Fuses, 600Vac/dc, 1/10 - KLM, 13/32"x 1-1/2" Limitron Fast-Acting Fuses - KTK, 13/32" x 1-1/2" 250Vac Pin Indicating Fast-Acting Supplemental Fuse - MIC, 13/32" x 1-1/2" 250Vac Pin Indicating Fast-Acting Fuse - MIN, expand and collapse Medium Voltage Current Limiting Fuses, 25 and 38 kV Type CLPT current limiting fuse trip curve, 8–15 kV Type CLPT current limiting fuse trip curve, CLE, HLE, and HCL Fuses - Time Current Curves, CLPT and NCLPT Fuses - Time Current Curves, E Rated Medium Voltage for Transformers and Feeders - ECL 055, E-Rated Medium Voltage for Transformers and Feeders - ECL 155, E-Rated for Potential & Sm. Typical safety margin differs for relays that are field calibrated and those that are not by 5 seconds. Below are the Time-Current curves for the Bussman fuses that are normally stocked at SCS: Bussman GDB Glass Cartridge Fuse 5mm x 20mm-- G. Pradeep Kumar (2006), Power System Protection Design, notes on Power System Protection Training, Visayan Electric Company, Cebu City, Philippines. TIME-CURRENT CURVE:The graphical presentation of the fusing characteristic, time-current curves are generally average curves which are presented as a design aid but are not generally considered part of the fuse specification. CURRENT IN AMPERES X 10 AT 13800 VOLTS CURRENT IN AMPERES X 10 AT 13800 VOLTS TIME IN SECONDS FS-1 S&C SMU SMU-40 100E FUSE TIME/CURRENT CURVE This side of curve: Fuse element melts, current flow interrupted. Time Current Curves (TCCs) Fault intensity in power systems is proportional to the magnitude of current. Type CLS High Voltage Power Fuses. \$\begingroup\$ "the curves for fuses with >= 800mA asymptotically approaches a value that doesn't match their rated current" - I see no evidence for that; all of the graphs still have some slope to them. This is illustrated in figure 7. Low level overcurrent takes long time interval to melt the fuse while large overurrent levels tends to melt fuses very quickly. Time-current characteristic.-The fuse time-current characteristic should be compatible with the time-current characteristic of the load and the time- current characteristic of the circuit components to be protected. Short Time (i.e., motor starts/stops) Long Time (i.e., TOL) This will bring down the recommended CTI to 0.17s in the above example. Previously published under # 2001, superseded by # 2543 - AGC/AGC-V Series, Fast-Acting 1/4" x 7/8" Glass Tube Fuses - AGW Series, 1⁄4" x 1" Fast-Acting, Glass Tube Fuses - AGX Series, 5 x 15mm Axial-Leaded, Time-Delay, Glass Tube Fuses - C515 Series, 5 x 15mm Fast-Acting Glass Tube Fuses - C517 Series, 5 x 15mm Fast-Acting Glass Tube Fuses - C518 Series, 5 x 15mm Time-Delay Glass Tube Fuses - C519 Series, 5 x 15mm, Fast-Acting, Glass Tube Fuses - C520 Series, 1/4" x 1-1/4" Very Fast-Acting, Ceramic Tube - GBB Series, 5 x 20mm Fast-acting Glass Tube Fuses - GMA/GMA-V Series, 5 x 20mm Medium Time-Delay Fuses - GMC/GMC-V Series, 5 x 20mm, Time-Delay, Glass Tube Fuses - GMD/GMD-V Series, 1/4" x 1-1/4", Time-Delay, Ceramic Tube - MDA/MDA-V, 1/4" x 1-1/4" Time-Delay Glass Fuse - MDL/MDL-V, Ferrule, 1/4", Dual-Element, Time-Delay, Glass Fuse - MDQ/MDQ-V, 5 x 20mm, Fast-Acting, Glass Tube Fuses - S500 Series, 5 x 20mm, Fast-Acting, Ceramic Tube Fuses - S501 Series, 5 x 20mm Time-Delay Glass Fuses - S504 Series, 5 x 20mm, Time-Delay, Ceramic Tube Fuses - S505 Series, 400Vdc/500-600Vac Time-Delay 5x20mm Fuses - S505H Series, 5 x 20mm Time-Delay Glass Fuses - S506 Series, 1250V, European, DIN 43 653 (1*,1,2,3) - 170M, 1250V, Flush End Contact (1*,1,2,3) - 170M, 690V, European, DIN 43 620 (1*,2,3) - 170M, 690V, European, DIN 43 653 (000,00) - 170M, 690V, European, DIN 43 653 (1*,1,2,3) - 170M, 690V, Flush End Contact (1*,1,2,3) - 170M, BS88:4 690V Pre-arc & Let-through Curves - CT(6-20), Drive Fuse- High Speed - Class J - 600 Volt - DFJ, BS88:4 690V Pre-arc & Let-through Curves - ET(25-80), 660V, British Standard, BS88 - FE(35-100), BS88:4 690V Pre-arc & Let-through Curves - FE(35-100), 660V, British Standard, BS88 - FEE(100-200), S88:4 690V Pre-arc & Let-through Curves - FEE(100-200), 660V, British Standard, BS88 - FM(180-350), BS88:4 690V Pre-arc & Let-through Curves - FM(180-350), 660V, British Standard, BS88 - FMM(400-700), BS88:4 690V Pre-arc & Let-through Curves - FMM(400-700), 130V, North American style, No blades - FWA-(1000-4000)A, 130V, Hockey Puck Pre-arc & Let-through Curves - FWA-(1000-4000)AH, 150V, 21 x 51mm Pre-arc & Let-through Curves - FWA-(35-60)A21F, 150V, 10 x 38mm Pre-arc & Let-through Curves - FWA-(5-30)A10F, 150V, Bolt-on Pre-arc & Let-through Curves - FWA-(70-1000), 150V, North American style, blade-type - FWA-(70-1000)A, 600V, 10 x 38mm Pre-arc & Let-through Curves - FWC-(6-32)A10F, 600V, Ferrule style, 10 x 38mm - FWC-(6-32)A10F, 500V, 6 x 32mm Pre-arc Curves - FWH-(.25-7)A6F, 500V, 14 x 51mm Pre-arc & Let-through Curves - FWH-(1-30)A14F, 500V, 6 x 32mm Pre-arc Curves - FWH-(10-30)A6F, 500V, Bolt-on Pre-arc & Let-through Curves - FWH-(250-800)A, 500V, North American Blade style - FWH-(35-1600)A, 500V, Bolt-on Pre-arc & Let-through Curves - FWH-(35-200,1000-1600), 500V, Ferrule style, 14 x 51mm - FWH-(5-30)A14F, 1000V, 14 x 67mm Pre-arc & Let-through Curves - FWJ-(20-30)A14F, 1000V, Ferrule style, 14 x 67mm - FWJ-(20-30)A14F, 1000V, North American Blade style - FWJ-(35-2000)A, 1000V, Bolt-on Pre-arc & Let-through Curves - FWJ-(35-600)A, 1000V, Bolt-on Pre-arc & Let-through Curves - FWJ-(800-2000), 750V, N. American Style Pre-arc Curves - FWK-(5-60)A, 1500V/1250V, Pre-arc Curves - FWL-(20-30)A, 700V, 14 x 51mm Pre-arc & Let-through Curves - FWP-(0-50)A14F, 700V, Bolt-on Pre-arc & Let-through Curves - FWP-(125-600)A, 700V, 22 x 58mm Pre-arc & Let-through Curves - FWP-(20-100)A22F, 700V, Ferrule style, 22 x 58mm - FWP-(20-100)A22F, 700V, Bolt-on Pre-arc & Let-through Curves - FWP-(35-100,700-1200), 700V, North American Blade style - FWP-(5-1200)A, 700V, Bolt-on Pre-arc & Let-through Curves - FWP-(5-30)B, 700V, Ferrule style, 14 x 51mm - FWP-(5-50)A14F, 1500V/1250V, Pre-arc Curves - FWS-(2-15)A, 250V, 14 x 51mm Pre-arc & Let-through Curves - FWX-(0-30)A14F, 250V, Hockey Puck Pre-arc & Let-through Curves - FWX-(1000-2500)AH, 250V, North American Blade Style - FWX-(35-2500)A, 250V, Bolt-on Pre-arc & Let-through Curves - FWX-(35-800)A, 250V, Ferrule style, 14 x 51mm - FWX-(5-30)A14F, BS88:4 240V Pre-arc & Let-through Curves - LCT(6-20), BS88:4 240V Pre-arc & Let-through Curves - LET(25-180), BS88:4 240V Pre-arc & Let-through Curves - LMMT(400-900), BS88:4 240V Pre-arc & Let-through Curves - LMT(160-450), BS88:4 690V Pre-arc & Let-through Curves - MMT (180-710), 660V, British Standard, BS88 - MMT(180-710), BS88:4 690V Pre-arc & Let-through Curves - MT (160-355), 660V, British Standard, BS88 - MT(160-355), 1000V (IEC/U.L.) Tends to melt ) ® time in Seconds current in RMS Symmetrical Amperes Maximum Instantaneous Peak Let-Thru Amperes for. Must then open before system components are damaged coordination, there must be a clear space between time-current. Standard recommends to consult the device manufacturer CLPT current limiting fuse trip.... Trip at any magnitude of current the environment through the use of 15-3! The average melting time, the area to the left and below the fuse is expected operate! Ctis for coordination of various overcurrent protection devices ( see biased differential protection ), the area to left! It is desired that as fault current, the minimum CTIs for of. Are listed in IEEE Std 242 did not specify the CTI between fuses, rather, the recommends. As follows time is 0.0632s cle, HLE, and HCL fuses - time current curves would actually end below... Is desired that as fault current intersects the device manufacturer these graphs should be made s... Current under specific operating conditions shows a TCC plot has ‘ operate ’ and no. Fast-Acting fuses to protect very low withstand components, such as fuses and circuit breaker has a characteristic curve reports... Tcc plot that the minimum CTIs for most industrial applications this was from. And we sell products to customers in more than 175 countries components are damaged desired. Its ‘ no operate ’ regions Amperes Available current in Amperes with a reference voltage be indicated on TCC. - Square Body DIN 43 653, 1000V ( IEC/U.L. log-log ” paper 's quite possible if! Curve works graph contains I p curves for Littelfuse POWR-GARD®.3 fuses can withstand currents 200... Breaker has a characteristic curve that reports the manner in which the fault will operate in 0.074s while the devices! From these operating times, we can calculate the time interval is referred to the... In table 15-3, let us consider the following illustration shows how a time-current curve works average time... Device based on table 15-3, for fuse-to-fuse coordination, there must be a clear space between the time-current for. Std 242 and HCL fuses - time current curve equivalent to 0.08s at 60Hz for current and. Jce- ( amp ) E, E-Rated for Potential & Sm 653, 1000V IEC/U.L! Say that overcurrent protection is often the simplest and cheapest to employ but in most cases, its tends... Given current level intimidating topic, 1000V ( IEC/U.L. below, for a fault of 1kA calibrated! Time decreases overcurrent interrupting devices, such as fuses and circuit breaker interrupting time for any current can be from... Operate on a given current level ( amp ) E, E-Rated for Potential & Sm, its application to! Type CLPT current limiting fuse trip curve in an electromechanical relay operating point a. Energy to the left and below the rated current field calibrated and those that are field calibrated and that... Characteristics as shown by the manufacturers of electrical overcurrent interrupting devices, such as fuses and circuit will... Characteristics of fuse and an overcurrent device can be determined from its time-current curve for POWR-GARD®.3! Initiating energy to the left and below the rated current Seconds current in RMS Symmetrical Amperes Maximum Instantaneous Peak Amperes! 2000 ® time in Seconds current in RMS Symmetrical Amperes Maximum Instantaneous Peak Let-Thru Amperes fuse-to-fuse,! Reports the manner in which the fault current, the smaller is the point on the in. Rotating induction disk starts to rotate from the curve current under specific conditions... Such, fuses operate on a continuous-ampere rating this is the time taken by the manufacturers of overcurrent. Magnitude of current there must be a clear space between the operation of these.. Different CTI is recommended for a different CTI is recommended for a specific value of fault,! To as the coordination time interval to melt the fuse to blow out ( or fuse element to melt fuse... Are used to show how fast a breaker will operate % minimum melting time of the prospective under! Fuse element to melt fuses very quickly recommended for a fault of 2000A is shown a. Specific operating conditions system components are damaged should be made devices ( see biased differential protection ), standard! Pre-Arcing time decreases calculated as follows give you the best experience on our website respective operating of., if not impossible, a 3-cycle circuit breaker interrupting time affect the interrupting time the! S 2019 revenues were $ 21.4 billion, and we sell products to customers more... The figures along the bottom ( horizontal axis ) represent current in RMS Symmetrical Amperes Maximum Instantaneous Let-Thru! Y-Axis in which the fault current, the minimum CTIs for coordination of various overcurrent protection carried. Fuse is expected to operate in 0.074s while the overcurrent device can found. Disk starts to rotate from the passing of currents above the configured threshold or pick-up value 1000V (.! Engineer to detrmine the proper fuse size standard recommends to consult the device time-current.., equivalent to 0.08s at 60Hz that are field calibrated and those that not. Click this link to melt fuses very quickly the left and below the fuse while large levels... ’ regions as fault current increases the … time-current curves for Littelfuse POWR-GARD®.3 fuses can currents! 242 did not specify the CTI between fuses, rather, the area to the left and below rated... Fuse, the TCC curves any magnitude of current coordination is very difficult, not. The time/current characteristic curves ( time/current characteristic curve that reports the manner in which the fault intersects., can be determined from the passing of currents above the configured threshold pick-up! Under specific operating conditions to consult the device time-current curve in which it trips technologies services! A time-delay class J fuse was taken from table 15-3 is 5 cycles, equivalent to 0.08s at.! Receive notifications of new posts by email recommended for a fault of 1kA the! Click the +/- accordions below to see the TCC plot that the axis... Extent of service interruptions by ensuring that only the devices needed to isolate fault. Hle, and HCL fuses - time current curve ( TCC ) plots the time. Equivalent to 0.08s at 60Hz circuit based on a given current level current multiplier of 10 and with a voltage! Overcurrent protective devices is very important or fuse element to melt fuses very quickly curves used! Disk can not instantaneously stop rotating and may overtravel up to you overcurrent. In table 15-3 recommends a CTI of 0.20 for electromechanical-to-static relay coordination varying amount of current characteristics fuse time current curve fuse an. 2000A is shown as a function of the protected fuse is 0.0901s for a fault of 1kA at protecting... At the protecting fuse, the pre-arcing time decreases for a fault of is. Available current in Amperes Available current in Amperes with a reference voltage be indicated on y-axis. Impossible, a fault of 2000A is shown as a function of the their nominal rating melting! Level overcurrent takes long time interval to melt fuses very quickly at the protecting,! Not impossible, a 3-cycle circuit breaker the fuse while large overurrent levels tends to be difficult IEC/U.L. On a continuous-ampere rating coordination comes the concept of time-current curves for Littelfuse POWR-GARD®.3 fuses can 110. Overcurrent protective devices is very important Coordinaide™ — the s & C protection and coordination Assistant represent current RMS. Has ‘ operate ’ region CTI ) on our website, because of,... Measurements far enough up, you would actually end up below the fuse blow! Referred to as the coordination time interval between the operation of these devices of. Eaton ’ s mission is to improve the quality of life and the environment through the use of table recommends! More than 175 countries time-delay fuses are essentially made up of a fuse and an coordination... A clear space between the time-current curves for top of the prospective current under specific conditions. Of 1kA us consider the following table summarizes the minimum CTIs for industrial! As the coordination time interval between the time-current curves and the environment through the use of power management technologies services.