Since 2006, manufacturers of custom control panels that have the ul listed. Supplement sb, provides an analytical method to determine the shortcircuit current rating of an industrial control panel. Ul 508a, supplement sb is an approved method to determine sccr for industrial control panels and industrial machinery control panels. First, the term motor controller in the default sccr table sb 4. The ul listing mark on an industrial control panel provides evidence of third party certification to the. Once you have all of the component ratings, either use an outside service or ul 508a supplement sb. These requirements also cover industrial control devices or systems that store or process information and are provided with an output motor control functions. Formerly supplement sa of ul 508a 1 listed components 1.
Latest facebook app for nokia s40 latest facebook app for n. A ul 508a certification is an industrial control panel directive, which electrical inspectors look for. Nec article 409 and ul 508a shortcircuit current ratings. Purchase ul standards online official ul standards sales. Overview of supplement sb from the ul 508a standard. Littelfuse using currentlimiting fuses to increase sccr pdf. Three basic changes have been made to the latest edition of ul 508a, supplement sb dated february 4, 2010. A brief history of ul 508a and tips for how control panel. Determine the overall panel short circuit current rating according to sb4. Underwriters laboratory implemented ul508a supplement sb.
Ul 508a supplement sb ul 508a supplement sb describes three steps to determine the sccr of industrial control panels. 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. Basic steps for calculating the sccr of a control panel. Eaton is a major component supplier that is committed to providing this information to our customers. Reference manual shortcircuit current rating sccr of. Multiple revision in 2017 slide alignment of ul508a with nec. Supplement sb in ul508a, which became effective on april 1, 2006, is referenced by the nec as an approved method for establishing the sccr of a panel. Per ul508a supplement sb, components that do, realized that any rating from this table is subject to meeting what ul defines as conditions of, inside the panel. Short circuit current ratings calculation and tools. The ul 508a supplement sb method does not require the panel to be listed. The component with the lowest sccr defines the sccr of the entire panel. Short circuit current rating sccr control concepts, inc.
This method is based upon the weakest link approach. Shortcircuit current rating sccr a first, establish the short circuit current ratings of individual power circuit components as specified in sb4. Other application information on sccr publications. 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. In order to open a secure pdf, you will need to install the fileopen plugin and register your computer. The elevator control panel shall not be installed where the available shortcircuit current exceeds its shortcircuit current rating, as marked in accordance with 620. Ul 508a standard pdf download a1d9fc608e share on facebook.
How to ensure troublefree approval of your ulcompliant. Ul508a 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. Control panel technical guide how to ensure troublefree approval of your ulcompliant control panels 8 2 ul standards and circuit design design of a motor circuit as per standard ul 508 part iv and ul 508a chap. 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, 3rd edition, supplement sb. The method stipulated in ul 508a, supplement sb, is also referenced in article 670, industrial machinery.
Simplify your panel design and project organization. The test has to be witnessed by a ul project engineer. Determining sccr for industrial control panels and industrial. Instruction sheets with sccr ratings ul tested combinations pdf. Purchase previously tested combinations from a major supplier that can be tabulated in the panel builders procedure. Determine the sccr of all individual power components and ul approved series ratings. Supplement sb is the ul approved method for determining the sccr for industrial control panels based on the power circuit components within the industrial panel. Test each panel construction and record the construction in a followup procedure. For many years, the ul508a supplement sb has been the approved method for calculation and determination of the short circuit current rating for industrial control panels. This rating is used to determine compliance with nec 110. With the numerous possibilities for product combinations within a panel, this option will require a tremendous investment in testing and maintenance. Sccr rating marked on the component use assumed sccrs in table sb 4.
An internet connection is required to open a secure pdf. Nec article 409 references ul508a supplement sb as an approved method for determining the sccr of an industrial control panel. 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. Ul 508a provides, tech topics will explain how ul 508a supplement sb is used to determine panel sccr and how the use of, training session on ul 508a, studied the standard in detail, and have firsthand field experience. How to determine shortcircuit current ratings iaei magazine. Shortcircuit current rating markings are not required for industrial control panels containing only control circuit components. All components in power circuit must have ratings ratings of starters are typically based on hp rating supplement sb, table sb4.
The table on page four from the ul 508a supplement sb lists the ratings of common unmarked components and their default sccr rating unless you have an alternative, such as a tested combination from schneider. Ansiul 508a, standard for industrial control panels, supplement sb, is an example of an approved method. And in the case of industrial control panels, change also tends to come slowly. Ul 508a standard pdf download gaaphakerslingbeachs blog. Control panel technical guide how to ensure troublefree approval of your ulcompliant control panels 6 1 ul standards and control panel design definition of electrical circuits as per standard ul 508a chap. Does my phase monitor realy require a short circuit. Supplement sb, provides an analytical method to determine the short circuit current rating of an industrial control panel. Short circuit current rating sccr is a rating on components and assemblies representing the maximum level of shortcircuit current that a component or assembly can withstand. It is a weakestlinkinthechain evaluation, meaning that the lowest sccr circuit within the panel.
Ul 508a supplement sb sccr method ul 508a supplement sb describes three steps to determine the sccr of industrial control panels. Ul 508a supplement sb is given as an example of an approved method. The sccr of the control panel is based on the sccr of each component in the power circuit. This translates to applying the method described in ul508a supplement sb for calculating the sccr for industrial control panels. Advanced guide to understanding assembly shortcircuit current rating simplified guide to understanding shortcircuit current rating find it, fix it, forget it spd selecting protective devices sections on industrial. Requirements for industrial control panel safety, implications of ul 508a 2nd edition panelbuilder 2 contents introduction 3. Ul 508a industrial control panels power distribution and.
Establishing the sccr for solid state relays per ul508a, shortcircuit current. Equipment intended to be connected to a source of supply greater. Determine the sccr of all individual power components by one of the following methods. Supplement sb, as an example for shortan approved method. Modify the sccr of certain series combinations if currentlimiting devices are used in the feeder circuit. A secure pdf license can be reassigned to a different computer if necessary. Tested product combinations to meet nec article 409 and ul. This is not a bad thing, mind you, because we must take care to ensure safety with control panels so its only fitting that our practices be tried and true. The secure pdf file needs to remain open for offline viewing. Furthermore, all industrial control panels listed to ul508a must be marked with their sccr. Underwriters laboratory implemented ul 508a supplement sb to. Sccr labeling is required on all panels and assemblies. Supplement sb is the ul approved method for determining the sccr for industrial.
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