Fuse coordination calculator All that is required is clear space (CS), except coordination of instantaneous trips cannot be demonstrated on TCCs. 56× safety factor per NEC 690. Apr 19, 2025 · Calculate and optimize electrical protection coordination using IEEE and NEC standards with our easy-to-use Protection Coordination Calculator. Mar 19, 2018 · The I²t (Ampere Squared Seconds) also known as Melting Point in a fuse. They comprise multiple tables for main (or upstream) and branch breakers. For mobile versions, download the mySchneider mobile app to access these tools and much more. Aug 3, 2021 · Calculate I²t of the circuit, find it in the chart, follow the vertical line. Besides revealing curve overlaps, E-Coord can also analyze the melting and clearing I²T value of every fuse and determine if any time-current overlaps exist that cannot be seen The Selective Coordination Analysis Tool provides you with the ability to select combinations of Circuit Breakers that provide total selective coordination (some in the industry refer to this as selectivity down to 0. It is convenient to think of the winding damage curve as a fuse located in series with the winding and shift its curve to coordinate with the device of interest (fuse or relay etc. Sep 18, 2024 · A coordination study analyzes the characteristic curves of the fuse and breaker and compares them to each other on a log-plot like the one shown in the following figure. The Selectivity Ratio Guide shows that the amp rating ratio must be maintained at 2:1 or more to achieve selective coordination. When the melting phase reaches FUSE-FUSE COORDINATION presents various tables for coordinating one type of fuse link behind another type of fuse link. 0), a tool to help users identify overcurrent protective device solutions that will coordinate (at 0. Select from the available attributes to find a fuse (s) that meets your application's criteria. Sep 18, 2019 · My question is what would be the minimum Coordination Time Interval for two electronically controlled reclosers considering that the downstream recloser curve already contains the manufacturer's maximum interrupting time and the upstream recloser curve is only the relay minimum response time?. Where medium and high voltage primary fuses are involved, the time-current characteristic curves of the fuses in question should be plotted on standard NEMA log-log graph paper for proper study. Understand the important factors to find the right fuse for your application. , overcurrent relays, fuses) to ensure that faults are cleared quickly and selectively. 01 seconds). SCD1. 42K subscribers Subscribe Superior protection with Bay-o-Net fuses Eaton's Cooper Power series transformer protection options include the standard Bay-O-Net draw out fuse in a standard or flipper configuration, a full line of low-current fuse cartridges, as well as under-oil ELSP partial range current limiting fuses that make coordination simple. Methodology for fuse and DC cable coordination: A fuse is the simplest overcurrent protection device (OCPD) in electrical circuits, yet it is very important. A mobile app and web-based application for determining the fault current of single- and three phase systems with fuse selection and conductor sizing guides. Let´s take an AC adapter for example. Protecting links One important criteria in selecting a fuse link is that it must coordinate well with upline devices. With Positrol Fuse Links, you eliminate unnecessary cutout operations and thereby reduce your maintenance and operation costs. Current-limiting fuses or current-limiting circuit breakers can reduce the risks associated with arc-flash hazards by limiting the magnitude of the fault currents (provided the fault current is within the current-limiting range) and reducing the time duration of the fault. Moved PermanentlyThe document has moved here. The required level of coordination will be determined by the prevailing electrical code and the local authority having jurisdiction . The Mersen FUSE-ION Configuration Tool will also provide a quote and download a PDF of the configured job. Discover the app. Close coordination is required Regardless of the preciseness of coordination, the fuse unit is subjected to temporary overloads There are cases where the coordination requirements may be very exacting, such as when coordinating a transformer primary fuse with a secondary breaker and a source-side breaker. However, if the motor is started last, you have to add the inrush to the existing load current and leave more margin for the fuse. This current-limiting action provides several benefits: Using the Correlation Charts Using Time-Current Curves Use Tables 3 and 4 to complete catalog number 4000353__. This presentation provides information for proper application of fuses when selective coordination is either desired for design or required by code In the second installment of a 4-part series titled Protective Device Coordination the Easy Way, Jim Chastain from EasyPower discusses fuse ratings, coordination rules of thumb using TCCs to confirm coordination of different manufacturers, current-limiting fuse energy let-through versus TCC plotting, and arc flash calculations using fuses. There is also an ALPHA version of a new fuse configurator, called confFUSE™, which utilizes an up-to-date device database. Once the measurements of current (I) and time (t) are determined, it is a simple matter to calculate melting I2t. By simply inputting a few pieces of data fields and selecting the desired level of protection, you can quickly find the right Eaton's Cooper Power series ELSP, MagneX Interrupter or Bay-O-Net fuses for your application. Overcurrent Coordination Setting Guidelines Transformers The information presented in this application guide is for review, approval, interpretation and application by a registered professional engineer only. 01 second) or selectively coordinate (all times all currents) in an electrical distribution system for up to 6 devices. Apr 11, 2025 · How to size fuses for solar panel systems correctly? Proper PV system fuse sizing requires calculating maximum current (including 1. Oct 28, 2014 · Thank you for your interest in Selective Coordination Designer v1. Type K Fuse Links Application The fast characteristics of Type K fuse links were established by ANSI/NEMA to provide fuse links that would meet existing coordination schemes. initially take 400A fuse for 200A continuous current) and draw the load profile next to 50% of the fuse breaking current-time chart to check if pulse currents can be carried by the fuse without aging. Click the +/- accordions below to see the TCC Curves. Professional protection coordination calculator for electrical engineers and protection specialists. The utility source fault level is 500MVA The contactors in series with fuses FS1/FS2 have a maximum breaking capacity of 3kA, and relay F2 has been set to ensure that the fuse operates before the SIMARIS curves The SIMARIS curves software, which also comes free of charge, visualizes characteristic curves with tolerance bands as well as setting options of specific parameters for low and medium voltage protective devices and fuses. Determine coordination time between a 225A MCCB and a 150A fuse. (UL) Medium Voltage Fuse Selector Surge Protective Device Selector Connector Selector Arcing Current Calculator SCCR Protection Suite FC2 Available Fault Current Calculator OSCARTM 3. Apr 20, 2025 · Calculate the right fuses for circuit protection quickly and accurately with our NEC-compliant Fuse Calculator. Reproduction of this material is permitted provided proper acknowledgement is Nov 12, 2001 · The fuse must lie above and to the right of the motor circuit protector curve up to the maximum fault current available for complete coordination, without exceeding the maximum size allowed by code. Choosing the right fuse for your application can be an overwhelming, time-consuming process, even for a seasoned electronics design engineer. n margins. Since the fuses used have a 3:1 ratio This calculator will help you determine an approximate fuse sized based on the circuit amperage when the wire size is already given or known. In order to maintain a properly functioning fuse coordination system, the fuse tables presented in this section must be followed in both system design and maintenance. ” When using the published Fuse Selectivity Ratios, drawing time current curves is not necessary for any level of overcurrent. The information provided in this document is meant as a guide only. Quickly estimate fuse size for your load with options for continuous duty, inrush allowance and fuse type recommendations. The coordination condition is a mathematical expression that determines whether the backup fuse will operate before the primary fuse blows. 16 kV through 34. Sep 26, 2025 · Fusing Transformer Calculator Use the tabs to select a method. bet ween the fuse total clearing -(1)Cordination can be easily h stream achieved relay curve wit couldd be low voltage current-limiting t where clearing fuses that times have b low fas response anufacturer's times. But be warned: That new version is barely tested! Our Fusing Calculator is designed to simplify the complex process of selecting the correct fuse size based on various key parameters such as wire ampacity, wire gauge, circuit voltage, ambient temperature, and circuit type. Manufacturer protective device time-current curve data with adjustable settings. This user-friendly Fuseology Selection Guide makes the fuse selection process quick Apr 20, 2025 · Calculate overcurrent and inverse-time relay settings accurately with our IEEE and IEC standard-based selection calculator for optimal protection coordination. This page provides links to an array of useful online tools, calculators and selectors. Learn proven methods to ensure optimal protection from overloads and short circuits. In the Selectivity Ratio Guide below, the top horizontal axis shows loadside fuses and the left vertical axis shows lineside fuses covering selectivity ratios for all levels of overcurrents up to the fuse interrupting ratings or 200kA A comparison of the time it takes protective devices to operate when certain levels of normal or abnormal current pass through them. With the new online version, you can do even more. Type QA fuse links will carry 100% of the rated current continuously without damage, and provide good coordination possibilities with relays and reclosers. 1 second or 0. The fuse rating calculation or fuse sizing formula is the 1. The current of such short This tool calculates fault current values for electrical systems, helping engineers ensure compliance with safety standards and optimize system design. I've read on a Littelfuse page that I2T of a fuse is a measure of the let-through energy. This tool calculates fault current values for electrical systems, helping engineers ensure compliance with safety standards and optimize system design. Each application can be used in a web browser. ) as we describe in preceding sections. Kearney Type QA fuse links are classified as “medium” speed fuse links with a nominal speed ratio of 10. Three combinations are possible: Upstream fuse and downstream fuse How to design selectivity in the overload and in the short-circuit zone Upstream circuit-breaker and downstream fuse How to design selectivity in the overload and in the short-circuit zone Upstream fuse Selective coordination reduces the likelihood of an unnecessary power outage and hence increases the reliability of the power delivery system. Use the same steps as in the previous paragraph. Identify Jul 22, 2020 · How do I select the breaking capacity of a fuse at the AC mains power input inside a product? The AC mains fuse box trips at 16A. Apr 20, 2025 · Calculate the correct protection fuse size for VFDs per NEC guidelines to ensure safe and compliant motor drive installations. Comprehensive Tables for Selective Coordination in Panelboards Table 1: Typical TransFusion coordination program This free, web-based, easy-to-use coordination tool makes transformer fuse selection effortless. Fuse coordination tables greatly reduce design time For example, the coordination table shows that POWR-PRO KLPC Class-L fuses coordinate at a 2:1 ratio with other Class-L fuses, with POWR-PRO LLNRK / LLSRK / LLSRK_ID series Class RK1 fuses, and POWR-PRO JTD / JTD_ID series Class J fuses In the system shown in Figure 7, Dec 31, 2023 · The Fusing Current Calculator is a practical tool designed to Estimate Total Fusing Time, Energy, and Cost for Glasswork or Metalwork Projects. The amp rating ratio of the two fuses in the system is 1200:400, which yields an amp rating ratio of 3:1. Ensure safety and code compliance easily. Fuse coordination is a critical step in properly sizing and selecting protective devices for your transformer designs. Every circuit breaker has a characteristic curve that reports the manner in which it trips. May 4, 2025 · Coordination Example: Coordination of protective devices involves selecting and setting protective devices (e. But in a I^2*T rating o Welcome to our calculators & tools page. For the purpose of this guide, transformers having primary voltage ratings between 34. 9 kV single-phase and 34. About this guide Fuses are current-sensitive devices that provide reliable protection for discrete components or circuits by melting under current overload conditions. Please select system type from these two: This installment explains how to coordinate two fuse links that are electrically in series; for example, a source-side lateral (sectionalizing) fuse link and a load-side transformer fuse link. Mar 18, 2025 · Calculate and select fuses for electrical circuits with precision. The mechanical & thermal design of the cable and busbar should be correct. These online tools aid in the selection of Bussmann series branch circuit, supplemental and photovoltaic (Low Voltage Fuse) and medium voltage fuses (Medium Voltage Fuse). You are allowed to dump the amount of energy proportional to that I²t as long as you do that over time expressed on the horizontal axis, if your vertical line is below the curve for a fuse. SKM disclaims any responsibility and liability resulting from the use and interpretation of this information. The program will also allow Selective Coordination when both fuses are known. Fuse selection made easier The Hi-Tech fuse application coordination tool, also known as Hi-Tech FACT, offers a simple, real-time solution to optimize backup current-limiting fuse selection based on the provided transformer configuration. Plotting the characteristics of each protective device using Time Current Curves (TCCs) is the ideal way to visualize proper coordination. This calculator does not superscede manufacturers recommendations. Learn more as we cover basics of power system protection, TCCs for the solid state and thermal magnetic trip, importance, procedure and rules of selective coordination here. Fuse - Relay coordination requires a minimum 0. Sep 28, 2024 · Q: How does the TCC of a fuse affect its coordination with other protective devices? A: The TCC of a fuse affects its coordination with other protective devices by determining the time it takes for the fuse to blow at a given current level. These are the parameters that should be used for the protective relay and coordination. We also discuss NEC requirements for service equipment to get skM powertools to calculate incident energy with Mersen’s Medium Voltage controllable fuse (MVcf) system, it is necessary to follow some simple guidelines when building the one-line, selecting components and running the analysis. these three parts of the program are reviewed below. How to calculate a Fuse rating ElectrikWave Online Academy 1. 0 Online Compliance Software Electrical engineering design software for protection coordination studies. How to make selectivity with fuses Here you can find the main rules to design selectivity between fuses or fuses and breakers. Mar 18, 2025 · Calculate selective coordination in electrical panels to ensure optimal circuit safety, fault management, and reliable power distribution within electrical systems. In addition to product specs, melting time and peak let-thru curves, and the ability to check fuse coordination, our enhanced Select-A-Fuse online tool features: Mar 29, 2024 · Explanation Calculation Example: Protection coordination is a crucial aspect of electrical engineering that ensures the selective and reliable operation of protective devices during a fault condition. 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. Aug 11, 2025 · Why do we calculate Fault Current? To evaluate to see that the circuit breakers, fuses, and switchgear have interruption ratings that are sufficient. The table displays: Welcome to the ABB Selective Coordination portal. Proper coordination of current-limiting fuses in the overload mode is ensured by keeping the fuse minimum melting curve above the total clearing curve of any downstream overcurrent protective device, and keeping the fuse total clearing curve beneath the minimum operating curve of any upstream protective equipment. It calculates settings to prevent unnecessary outages and equipment damage. Includes input fields for load, duty, and correction factors for safe fuse selection. Mar 18, 2025 · Calculation of Electrical Protection Coordination ensures safe, reliable power systems by optimizing relay settings, fault analysis, and trip timing for effective protection. Enter any 2 values in the active tab to calculate the missing value. 5 kV Coordination chart for Kearney type K fuse links Protected fuse link Protecting fuse link Apr 20, 2025 · Calculate transformer protection per NEC standards quickly and accurately with our easy-to-use NEC Transformer Protection Calculator. 0 (SCD1. Mar 15, 2016 · Design engineers must coordinate electrical systems so that the protective device closest to the fault opens first, and quickly enough, to prevent the upstream devices from tripping. The purpose of this rating is to assure that the heat created across the fuse during a surge has insufficient time to thermally conduct away from the fuse to external circuitry. though it is generally easy to achieve selective coordination in an all-fuse system, such a system may not be practical. However, the fuse characteristic should be below the transformer damage curve, namely, on the lower current and shorter time side on the I-t coordination chart. This is because the downline fuse is protecting the upline, protected fuse by operating for overcurrent conditions which are downline of the protecting The Schneider Electric selective coordination resource center provides expert guidance for meeting codes and standards to help make your design process easier and more cost-effective. g. This is where you will find useful information for coordination studies and determining selectivity between overcurrent devices. Jan 15, 2022 · The fuse selection procedure is highly similar to contactor selection and complementary parameters help how to select EV fuses. Aug 30, 2024 · Explore comprehensive fuse calculation and selection methods for electric vehicles, including detailed guidelines on fuse types, voltage considerations, and practical examples for safe and efficient circuit protection. Nov 3, 2015 · Coordination Time Intervals – Banded Devices Banded characteristics include tolerances & operating times. AVR® Fuse Calculator Welcome to the classic AVR Fuse Calculator. During a "single fault", using 62368-1 I imagine making a short-circuit of the mosfet drain-to-source. Reproduction of this material is permitted provided proper acknowledgement is Aug 11, 2025 · Make the right choice with this fuse selection guide. Calculate the components and the fuse breaking energy (I 2 Rt) to ensure that the weakest component is the fuse. May 11, 2004 · The transformer protecting fuse I-t characteristic should pass this point on the higher current and the longer time side on I-t coordination chart. Use fuses for high fault current and current-limiting needs. Overcurrent device protection and coordination evaluation software. H-J has long provided this service for our customers via an offline service, and the algorithms have been refined over the past decades. Use 15-30A fuses for residential strings and 100-400A for combiners. Analyze coordination between a 600A feeder breaker and 200A branch breakers. Objective of Power System Protection: The primary objective of power system Coordination chart for Kearney type K fuse links Protected fuse link Protecting fuse link Mar 18, 2025 · Explore NEC standards for calculating fuse and circuit breaker sizing to ensure optimal safety, efficiency, and code compliance in electrical installations. 5 times of the lighting load Apr 19, 2025 · Calculate the ideal protection fuse per NEC and IEC standards quickly and accurately with our easy-to-use Protection Fuse Selection Calculator. For low-voltage power circuit breakers to molded-case circuit breakers (MCCB), coordination values are derived from time current curves with instantaneous in OFF position for power circuit breaker . Nov 26, 2024 · Learn how to select and coordinate American transformer protection fuses, including Bay-O-Net (BON) and ELSP backup fuses. This program allows the user to quickly determine either the required line side fuse or the required downstream or load side fuse. Characteristic cut-off current and let-through energy curves are also displayed. The Protection coordination device is used to quickly calculate the tripping times associated with the selected curves of overcurrent elements (OCEs) in the design for a given fault current level. Superior protection with Bay-o-Net fuses Eaton's Cooper Power series transformer protection options include the standard Bay-O-Net draw out fuse in a standard or flipper configuration, a full line of low-current fuse cartridges, as well as under-oil ELSP partial range current limiting fuses that make coordination simple. Fuse - Low Voltage Breaker coordination requires that the down-line breaker maximum time curve be less than 75% of the minimum melt time of the up-line fuse curve to account for pre-loading. Additional Tables for NEC Protection Optimization This information bulletin is a guide for the selection, appli-cation, and coordination of S&C Type SMD® Power Fuses when applied on the primary side of small to medium-sized transformers installed in utility and industrial substa-tions. The scope of this tool encompasses only breaker-to-breaker short circuit selective coordination. Apr 19, 2025 · Calculate accurate fuse and breaker sizes per NEC standards quickly and easily with our Fuse and Breaker Sizing Calculator. Mar 18, 2025 · Master fuse calculation for circuit protection by matching current ratings and safety margins to prevent overloads and ensure efficient electrical systems. The ABB Installation Products Hi-Tech® fuse application coordination tool ("the program") is designed for use by electrical utility specification engineers, transformer designers and manufacturers, and electrical power consultants. Selective coordination using fuses Adhering to published fuse selectivity ratios makes it easy to design and install a selectively coordinated fusible system. Explore guidelines for inrush current, short-circuit scenarios, and practical recommendations to ensure transformer safety and reliability. Current-limiting fuses are capable of isolating a faulted circuit before the fault current has suficient time to reach its maximum value. The Volt drop, ac volt drop and DC volt drop are all calculated for fuse selection or motor fusing with a combination of AC Voltage Drop, DC Voltage drop and Series voltage drop. Multiply that by time and you have energy. Mersen engineers will also work with you to design a solution that fits your Fuse coordination is a critical step in properly sizing and selecting protective devices for your transformer designs. By using this tool, you can quickly get accurate recommendations that comply with safety standards and maximize the reliability of your electrical installation. For two fuses in series, the downline fuse is called the protecting fuse while the upline fuse is called the protected fuse. Let-Thru Current and l2t Current limitation is one of the important benefits provided by modern fuses. Use breakers where reset capability and coordination with downstream loads is essential. FACT provides multiple types of expulsion fuses common in the industry, allowing users to select a specific rating as needed when defined by industry or Coordination studies are required to select or verify the clearing characteristics of devices such as fuses, circuit breakers, and relays used in the protection scheme. A fuse is a two-terminal device that is placed in series with the circuit it is supposed to protect. Evaluate selective coordination for a panelboard with multiple 60A circuit breakers. . 5 kV and 138 kV, with medium-voltage (4. Selectively coordinate two or more devices in series to minimize service interruptions. Ensure safety and compliance easily. Time grading with fuses is also easier to obtain with inverse time relays. 25 times of the FLA for motor, 2 times of the FLA for transformer, 1. The table is based on maximum-clearing time curves FL3T for protecting links and 75 percent of minimum-melting time curves FL3T for protected links. Apr 20, 2025 · Calculate selective coordination for a 400A main breaker with 100A downstream breakers. Quick links to pre-filtered listings of tripping curves available in our download center. 3 second time margin between the curves. 0 Online Compliance Software Apr 20, 2025 · Calculate the correct fuse size for electrical circuits quickly and accurately with our NEC-based Fuse Selection Calculator. Discover the fundamentals of fuses, their types, and applications in electrical systems for effective circuit protection. This makes it possible to optimize the final fuse selection. But be warned: That new version is barely tested! Apr 19, 2025 · Calculate accurate fuse and breaker sizes per NEC standards quickly and easily with our Fuse and Breaker Sizing Calculator. Overcurrent Device Look-up Tables and System Design Guide Our selective coordination look-up tables are quick and easy to use. Apr 20, 2025 · Protection coordination ensures selective and reliable operation of protective devices in industrial electrical systems. Sep 17, 2025 · Breakers vs Fuses: Which to Choose? Choosing between breakers and fuses depends on response time, selectivity, coordination, and cost. There is no intentional/ additional time delay needed between two banded devices. In the system shown in Figure 1 the problem is to calculate appropriate relay settings for coordination between IDMT numerical relays 1-5 inclusive. Related Questions The SELECTIVITY GUIDE on page 10 may be used for an easy check on fuse selectivity regardless of the short-circuit current levels involved. FUSE-FUSE COORDINATION presents various tables for coordinating one type of fuse link behind another type of fuse link. If you want to give it a try, switch to confFUSE™. Welcome to schneider electric's fault current calculator. As this curve is reporting the amount of current vs time, it is a Positrol® Fuse Links are designed to provide reliable protection, and they operate only when a fault occurs within the cutout’s zone of protection. The units of amps^2*resistance is power. This tool provides circuit breaker selections that are fully rated Fuses Check the LPJ-400SP fuse coordination with the KRP-C-1200SP fuse. Apr 20, 2025 · Calculate transformer protection per NEC standards quickly and accurately with our easy-to-use NEC Transformer Protection Calculator. Critical steps include analyzing fault . 5 kV three-phase ap pli ca tions, an coordinate with up stream and down stream system re quire ments, ELSP current-limiting backup fuse is recommended. The Electrical designer or electrical designer’s Reference also does short-circuit current on a radio network This table show maximum values of fault current at which EEI-NEMA Type T fuse links will coordinate with each other. The fusing philosophies described in this document have been used for many years to create fuse selection and coordination tables for Eaton’s Cooper Power series fuses used in pad-mounted transformer applications. Ensure electrical safety and compliance. Simply match the Oct 6, 2025 · Quickly calculate the recommended fuse (fusing) current for wires, motors, transformers, and circuits. Analyze selectivity, time-current curves, and coordination margins per IEEE standards with comprehensive protection system design and arc flash considerations. These studies are also needed to determine the protective device settings that will provide selective fault isolation. The EDR is the best way to calculate wire gauge through voltage and fault current electrical calculators. Fuse-to-Fuse and Fuse-to-Upstream circuit breaker selective coordination tables Selective coordination tables of tested fuse to upstream fuse and fuse to upstream circuit breakers for use in achieving selective coordination in a building's electrical system. 5 kV Oct 27, 2020 · Time Current Characteristic Curves play a significant role in achieving proper protection coordination among the electrical safety devices. (See Catalog use time-current Selecting a Fuse Select a fuse rated double as continuous current (e. 0 is easy to use: Enter your circuit (system) details for the portion of the Moved PermanentlyThe document has moved here. Overview The Elite Software E-Coord Program aids in the selective coordination of fuses and circuit breakers by providing an instantaneous review of their time-current curves in a proposed electrical protection system. Sep 10, 2018 · Calculation of IDMT Over Current Relay Settings (50/51/50N/51N) Calculation model for thermal relay Siemens 7SJ6 Motor Protection Relay Selection Curves Over-current protection – INVERSE TIME O/C PROTECTION CALC – 51 (N) – Directional OC Filter Design Calculation P63x Differential CurrentsCalculation MiCOM P634/P633/P632 Calculating the operation current in Bias Differential Relays MiCOM Overcurrent Coordination Setting Guidelines Conductors The information presented in this application guide is for review, approval, interpretation and application by a registered professional engineer only. Consi-dering the above arguments and also taking into account, for example the short-circuit current withstand capacity of the network components, applying inverse time relays for the network short-circuit protection may be justified. We are proud to deliver this service to customers with an online tool which allows user real-time feedback and information which you need in For analyzing fuse selective coordination for higher level fault currents see the next page, “Medium to High Level Fault Currents–Fuse Coordination. Protective & Coordination and Selectivity Analysis software provides an intuitive approach to Time-Current Characteristic (TCC) curve analysis. The Mersen FUSE-ion Configuration Tool lets Mersen partners design your own custom-configured Fused Coordination Panelboard by selecting the ratings, features, and options you want via a graphical interface. Chance Type K fuse links are designed to carry 150% of their rated current without damage to the fuse link itself or the cutout in which it is installed. For To determine or confirm the current sensing Bay-O-Net fuse that will 19. S metimes thesed intervals for coordination are calle purposes. When selecting low-current protection devices and backup fuses, proper fuse coordination is critical to insuring full-range transformer protection. Discrimination depends on type and size. 8), evaluating short-circuit conditions, matching fuse ratings to wire ampacity, and accounting for temperature derating. Comprehensive Tables for Selective Coordination in Panelboards Table 1: Typical AVR® Fuse Calculator Welcome to the classic AVR Fuse Calculator. The user choses which OCEs to investigate, adds them to the results table and then enters the desired fault current in per unit. This calculator aids in determining the operating characteristics of overcurrent relays based on fault current levels and CT ratios. current-limiting fuses placed in strategic circuits and selectively coordinated To determine or confirm the dual sensing Bay-O-Net fuse that will coordinate with up stream and down stream system re quire ments, use time-current characteristic curves and specify the fuse in di cated from Table 2.