How to determine shortcircuit current ratings iaei magazine. Formerly supplement sa of ul 508a 1 listed components. Ul 508a supplement sb sccr method ul 508a supplement sb describes three steps to determine the sccr of industrial control panels 1. Basic steps for calculating the sccr of a control panel. Ul 508a industrial control panels power distribution and control. Ul 508a supplement sb is the preferred option for nearly all industrial control panels. Designing for safety compliance in industrial control panels, ul 508a and shortcircuit current ratings elearning. Littelfuse using currentlimiting fuses to increase sccr pdf.
Latest facebook app for nokia s40 latest facebook app for n. We design, assemble, and install ul certified panels and can bring existing control panels up to ul safety standards, as well as build panels from the ground up meeting the customer requirements, while following ul safety standards. Requirements for industrial control panel safety, implications of ul. This document will be updated on an asneeded basis as changes occur in the use of components in panels. Ul 508a standard ul 508a standard is industrial control panels the standard covers industrial control panels intended for general industrial use, operating at a voltage of 600 volts or less this equipment is intended for installation in ordinary locations, in accordance with the national electrical code, ansinfpa 70 supplement sb is included to help determine sccr for. The ul 508a supplement sb method of assigning the sccr to an industrial control panel does not require the panel be listed. Ansi ul 508a, standard for industrial control panels, supplement sb, is an example of an approved method. This guide replaces neither the standards including ul 508a that electrical equipment must comply with nor the requirements of standard profes sional practice. Each copy is watermarked with the purchasers information. This is typically somewhere between 240vac 600vac, 3 phase power. Ul508a standard for industrial control panels document. Purcell systems manufactures ul 508a certified enclosures and cabinets to the ul 508a safety standard this manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent damage to property. Ul 508a20, supplement sb, is an example of an approved method. Shortcircuit current rating sccr a first, establish the short circuit current ratings of individual power circuit components as specified in sb4.
Nec article 409 and ul 508a shortcircuit current ratings. Ul 508a 20, supplement sb, is an example of an approved method. Ul 508a sb method for determining panel sccr feeder branch feeder branch primary protection 1. Control components branch and feeder circuits power transformer vs. Ul 508a, supplement sb, provides an analytical method to determine the shortcircuit current rating of an industrial control panel. Ul 508a supplement sb sccr method ul 508a supplement sb describes three steps to determine the sccr of industrial control panels. This document is intended to be used to determine the requirements for components when used in industrial control panels. Excerpts from ul 508a standard for safety for industrial control panels are the.
This award winning design tool allows you to comply quickly and accurately with 2008 nec and ul 508a supplement sb for assembly sccr marking requirements. Ul standard for safety for industrial control panels. Ul 508a covers industrial control panels and industrial panel enclosures operating at 600. Using currentlimiting fuses to increase short circuit. The second day instructs industrial control panel customers on how to establish shortcircuit ratings for individual industrial control panels in accordance with the requirements outlined in the new standard for industrial control panels, ul 508a, 2nd edition, supplement b. This method is based upon the weakest link approach. The ul listing mark on an industrial control panel provides evidence of third party certification to the municipal inspection authority and to the purchaser of the panel.
Modify the sccr of certain series combinations if currentlimiting devices are used in the feeder circuit. The elevator control panel shall not be installed where its the available shortcircuit current exceeds its shortcircuit current rating, as marked in accordance with 620. Using current limiting fuses in the panel feeder could protect components that are not marked or have a low sccr and allow for the overall panel sccr to be higher than an individual component. Designing for safety compliance in industrial control panels. This guide replaces neither the standards including ul 508a that electrical. The current version will be stored on ul s industrial control panel website. Once you have all of the component ratings, either use an outside service or ul 508a supplement sb. Ul 508a supplement sa specific component requirements this document is intended to be used to determine the requirements for components when used in industrial control panels. Learn critical safety compliance requirements of the ul 508a standard for industrial control panels and the new requirements found in the national electrical code nec article 409 and ul 508a supplement b in our interactive twoday workshop. Control panel technical guide how to ensure troublefree approval of your ul compliant control panels 6 1 ul standards and control panel design definition of electrical circuits as per standard ul 508a chap.
Ul 508a sb determining sccr three basic steps ul 508a supplement sb shortcircuit current ratings for industrial control panels shall be determined by the following evaluation procedure. Per the ul 508a guideline a power transformer rated 5kva or lower will limit the fault to 2ka on the secondary side of the transformer section sb4. The table below is extracted from the ul 508a supplement sb, table sb4. At the municipal, county and state levels, electrical codes are being amended at an increasing rate to include the requirement for sccr labeling of industrial control panels per nec409. Sccrs are required to be marked on industrial control panels and other equipment in accordance with the product standards and thenec. These requirements also cover industrial control devices or systems that store or process information and are provided with an output motor control functions. The sccr for components typically is determined by testing. Benefits of selecting an enclosure or cabinet that carry the ul 508a certification include. In order to open a secure pdf, you will need to install the fileopen plugin and register your computer. Underwriters laboratory 508a overview of ul508a supplement sb ul 508a is a safety standard for industrial control panels adopted by underwriters laboratory, which is an approved method in determining sccr referenced by nec article 409.
Ul 508a for functional design and the calculation of ratings applicable standards from beginning to end of a project product selection. These standards ensure public safety, and provide assurances. It is the responsibility of the equipment manufacturer to ensure compliance with all applicable standards. Supplement sb, provides an analytical method to determine the short circuit current rating of an industrial control panel. We will help with the acceptance ul 508a standard pdf download a1d9fc608e share on facebook in industrial control panels according to ul508a. The nec article 409 refers to the ul 508a supplement sb as an approved method for determining the sccr of an industrial control panel. Ul508a supplement sb4 is the approved method for determining short circuit. Test each panel construction and record the construction in a. Prior to the release of the latest edition of ul 508a, supplement sb dated december 20, 20, sccr applied only to the power circuit of a control panel. Ul 508a covers industrial control panels and industrial panel enclosures operating at 600 volts. References in this document to sections or paragraphs in ul 508a are understood to be to the third edition of the standard with revisions dated july 3, 2018.
The north american electrical safety system changes affecting industrial control panels a white paper on ul 508a, nec 409 and related codes and standards changes that affect panel builders, machine builders and those who design and develop industrial control panels. Pdf 16xxx 140023 ul, tb30003sp ul, ndn63wh ul, ndn111wh ul ul1953 ul1059 sb bu09622 pdbfs series pdb series 163711. Ul 508a, standard for industrial control panels, supplement sb, is an example of an approved method. The 508a standard for industrial control panels is the premier document for designing and constructing for compliance with the national electrical code. Sa in the second edition of ul 508a, and subsequently.
Ul 218 fire pump controllers ul 508a industrial control panels ul 508c power conversion equipment adjustablespeed drive and accessories or modules for use with an adjustablespeed drive ul 845 motor control centers ul 6094741 lowvoltage switchgear and control gear, part 41. Underwriters laboratory implemented ul508a supplement sb to. Please refer to the ul website to view the most uptodate table sb4. This document replaces what was supplement sa in the second edition of ul 508a, and subsequently appendix c in the third edition of ul 508a. Ul508a is the ul standard for the construction of industrial control panels. Equipment sccr, industrial control panel devices and ul 508a supplement sb. As testing is always time consuming, as well as incurring signi. This document gives guidelines to panel builders on various issues including proper component selection, wiring. With the numerous possibilities for product combinations within a panel, this option will require a tremendous investment in testing and maintenance. Ul knowledge solutions industrial control panels ul 508a. Modify the sccr of certain series combinations if current limiting devices are used in the feeder circuit. Using currentlimiting fuses to increase sccr industrial control panels article 409 industrial machinery electrical panels article 670 multiple motor hvac equipment article 440 meter disconnect switches article 230 multiple motor controllers article 430 although sccr markings and labels are required by several. Schneider electric codes and standards 2017 nec changes.
Nec article 409 and ul 508a shortcircuit current rating sccr of industrial control panels. Ul 508a control panel design guide the easytodesign guide for selection of electrical control components in control panels used in industrial machinery applications this guide is provided to assist with the design of control panels per ult 508a, specifically for use in industrial machinery applications. How to facilitate the ulcompliant approval to your control panel. Supplement sb, provides an analytical method to determine the shortcircuit current rating of an industrial control panel. Ul 508a is a standard covering industrial control panels. Determining sccr for industrial control panels and. Welcome to the training and certification center on controldesign. The power circuit supplies electricity to the workers that do the heavy lifting, powering large motors, for example. Ul 508a supplement sb defines a procedure for determining the equipment sccr. The workshop is ideal for those who need to understand the safety compliance requirements of the ul 508a standard for industrial control panels, as well as the new requirements found in the national electrical code nec article 409 and ul 508a supplement b. Ul 508a standard for industrial control panels standards. Determination of the sccr values of individual components. Requirements for industrial control panel safety, conductors. Ul 508a certification provides the inspection authority and your customer evidence that the control panel complies with nationally recognized safety standards.
A ul 508a certification is an industrial control panel directive, which electrical inspectors look for. Fpn reference to ul 508a supplement sb as an example of an approved method for determining the sccr that may be marked on the panel. Ul 508a supplement sa specific component requirements ul. As specified in the national electrical code nec, ul 508a supplement sb, the. Ul 5084891077 98508508c512 for verification of the presence of certificates of product compliance with applicable manufacturing standards. Tested product combinations to meet nec article 409 and ul. F, type f combination motor controller consisting of manual selfprotected. This document comes with our free notification service, good for the life of the document. Ul now offers the ability to purchase a premium hard copy of any ul standard. A secure pdf license can be reassigned to a different computer if necessary.
Short circuit current ratings for combination motor. Overview of nec article 409 shortcircuit current rating sccr of industrial control panels 10 reference manual, 0620, a5e31896849002arsaa001. Ansiul 508a, standard for industrial control panels, supplement sb, is an example of an approved method. Identify the interrupting rating for each overcurrent protective device. Ul 508a industrial control panels power distribution and. Test each panel construction and record the construction in a followup procedure. This comprehensive one and a halfday workshop provides technical information to industrial control panel professionals. The introduction of new article 409 for industrial control panels in the 2005 edition of the national electrical code nec drew increased attention to installations of industrial control panels icps. Purchase ul standards online official ul standards sales. Reference manual shortcircuit current rating sccr of. Short circuit current ratings for industrial control panels april 2006 page 4 of 12 overview of supplement sb from ul 508a ul508a is the safety standard for industrial control panels. Therefore, because the rating of all of the devices on the secondary of the transformer are greater than 2ka, the sccr of the panel in this example would be 65ka.
Determine the sccr of all individual power components and ul approved series ratings. Nec article 409 and ul 508a shortcircuit current ratings sccr. Power distribution block application ul 1995 example ul508a, table 28. Ul 508a, supplement sb is an approved method to determine sccr for industrial control panels and industrial machinery control panels. Ul 508a standard pdf download gaaphakerslingbeachs blog. Short circuit current ratings calculation and tools. In this example, the 125a circuit breaker is the largest shortcircuit protective device. Shortcircuit current rating markings are not required for industrial control panels containing only control circuit components. Ul 508a standard for industrial control panels purcell systems. The elevator control panel shall not be installed where the available shortcircuit current exceeds its shortcircuit current rating, as marked in accordance with 620. Firstly, by having the system tested to a recognised veri. Overview of supplement sb from the ul 508a standard. An internet connection is required to open a secure pdf.
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