UL508Afor Panel Builders Getting Started Restricted Siemens AG 2016 siemens.tld/keyword
Exclusion of Liability The typical circuit diagrams and interpretations of the standard are not binding and do not claim to be complete regarding configuration, equipment or any other eventuality. They do not represent any client-specific solutions and are only intended to offer assistance for typical tasks. Each person viewing this presentation is responsible for the correct operation of the products described. This presentation does not relieve you of your responsibility regarding safe handling when using, installing, operating, and maintaining the equipment. By viewing this presentation you agree that Siemens cannot be made liable for possible damage beyond the above mentioned liability clause. We reserve the right to make changes and revisions to this informational documentation without prior announcement. When writing these guidelines, a lot of tables and texts were lifted straight from the relevant standards. All users of this documentation must always check whether the items quoted are still up to date or not. The final decision about the appropriateness of applying the applicable standards must be made by the user of this documentation. The reproduction of this presentation and its distribution, utilization or the dissemination of its contents to third parties is not permitted. Page 2
Speaker Jeff Woolfolk Bachelor of Science, Electrical Engineering Technology System Consultant Digital Factory Control Products Application consulting: - North American Standards and Codes - European Directives and international IEC/ISO standards www.usa.siemens.com/controlpaneldesign www.usa.siemens.com/planning-efficiency Page 3
Differences between USA and everywhere else = Page 4
Excerpts of the OSHA standards and NEC Ed. 2014 OSHA 1910.303(b)(2) Subpart S Electrical / General requirements: Installation and use: Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling. Definitions acc. NEC Art. 100: Equipment: A general term, including fittings, devices, appliances, luminaires, apparatus, machinery, and the like used as a part of, or in connection with, an electrical installation. Listed: Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. Labeled: Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards etc. Page 5
Relevant standards for panels for the US market Page 6
Comparison between USA and IEC standards IEC 60364-1 IEC 61439-2 IEC 60204-1 Page 7
UL508A Industrial Control Panels 1893 World Exhibition in Chicago Outbreak of a fire 1894 Start of UL William H. Merrill opens the Underwriters Electrical Bureau Page 8
National Fire Protection Association Foundation: 1896, due to increasing sprinkler system installations Headquarters: Quincy, Massachusetts Publication of over 300 standards to date National Electrical Code or NFPA70 NFPA79 Electrical Standard for Industrial Machinery Standardization organization in the field of fire protection, electrical safety and building safety Page 9
NFPA (nec) and UL508A work together Page 10
NFPA (nec) and UL508A work together When it comes to Industrial control panels the NEC 2014 refers still to UL 508A! Recommendation: Industrial control Panels should fulfill furthermore the UL 508A Maximum voltage 600V! UL 508A is still limited to 600V or less! Page 11
Most Important Network Types in Detail Grounded wye / solidly grounded wye Slash rating: e.g.: 480Y/277V, solidly grounded wye 3 phase; 4 wire 3 phase; 3 wire Possible devices 480Y/277V; 600/347V 480V; 600V Transformer 3p, 4w / grounded phase-ground U = 277 V across one contact worst case! I k 480Y/277V AC L1 L2 L3 Note: All devices having a slash rating with the indicated voltage or higher All devices having a delta rating with at least the higher of both voltages M Page 12
Most Important Network Types in Detail Corner grounded delta Straight (Delta) rating: e.g.: 480V / 3 phase - 3 wire Transformer 480V AC L1 L2 L3 Possible devices in this example: 480V; 600V I k Phase - Ground Do not use: 480Y/277V; 600Y/347V U = 480 V across one contact worst case!! Note: The devices switch full (=high) voltage at the first single pole short-circuit (phase to ground) M The following applies to this network in principle: Only devices with delta rating must be used! Page 13
Most Important Network Types in Detail Ungrounded delta - Ungrounded wye Straight rating: e.g.: 480V / 3 phase - 3 wire Transformer Δ/Y 480V AC L1 L2 L3 Possible devices in this example: 480V; 600V Do not use: 480Y/277V; 600Y/347V Note: Phase - Phase U = 480 V across one contact worst case!! The devices switch the full (=high) voltage at the second single-pole short-circuit (phase to ground) I k! Operation Betrieb requires Insulation monitoring! Insulation measuring M The following applies to this network in principle: Only devices with delta rating must be used! Page 14
UL Category Code Numbers The CCN represents a clear description of the respective product The respective CCN Guide Information clearly describes how and under which conditions the respective product can or may be applied (www.ul.com/database) Every AHJ or UL inspector can thus verify whether the respective product was correctly configured and applied The CCN should be additionally integrated in the parts list Examples: DIVQ // DIVQ7 // NMTR2 // NMTR8 Page 15
UL508A Table SA1.1 Page 16
(www.ul.com/database) Page 17
UL508A Short Circuit Current Rating (SCCR) Requirement of NEC 2005 Art. 409 (mandatory since April 26, 2006) Re-enforcement of the standards for industrial control panels Failures in determining the short-circuit current rating (= SCCR) of an industrial control panel. For the short-circuit current rating not only the short-circuit breaking capacity of, e.g. the circuit breaker is needed, also the short-circuit current rating of every individual device is as relevant. SCCR-relevant components in the power circuit, such as: Circuit-breakers, contactors, soft starters, overload relays, but also Terminals, busbars, Supply to an control transformers, Frequency converters, Further current limiting effects are not allowed to be considered e.g.: that of wires, cables, busbars, Page 18
UL508A Short Circuit Current Rating (SCCR) NEC Article 409.110 Marking An industrial control panel shall be marked with the following information that is plainly visible after installation:. (4) Short-circuit current rating of the industrial control panel based on one of the following: a. Short-circuit current rating of a listed and labeled assembly b. Short-circuit current rating established utilizing an approved method Informational Note: ANSI/UL 508(A), Standard for Industrial Control Panels, Supplement SB, is an example of an approved method. Exception to (4): Short-circuit current rating markings are not required for industrial control panels containing only control circuit components Page 19
UL508A Short Circuit Current Rating (SCCR) Determination of the short-circuit current rating (SCCR) acc. to NEC409.110 (4): Step 1: necessary! SCCR of the installed and UL-listed components Step 2: necessary! Establishment of the SCCR on the basis of standard values (UL508A suppl. SB or UL-guide; chapter 5.8.4). Step 3: Optional, very helpfull! SCCR of tested industrial control equipment assemblies (series rating = 2 circuit breakers in series or combination tests = motor branch circuits) Step 4: Optional, not very helpfull! Use of current limiting devices (transformers, fuses, circuit breakers) Page 20
UL508A Short Circuit Current Rating (SCCR) Page 21
UL508A Short Circuit Current Rating (SCCR) List the short circuit current ratings of components, from UL 508A, Table SB 4.1, if no values on the nameplate or on instructions provided with the components (see step 1) Establishment of the SCCR value using the table in UL508A. These standard values must be used if the technical documents do not provide SCCR values for the applied devices. Page 22
UL508A Short Circuit Current Rating (SCCR) SCCR of tested industrial control equipment assemblies Series rating tests Series connection of 2 or more devices, which are able to automatically respond in short circuit cases without delay. SB4.3.2 in UL508A! Current limiting cannot be used here! Combination tests Series connection of any type of devices, e.g.: Motor protection circuit breaker and contactor (=fuseless load feeders as type F acc. to UL508) MCCB and terminal block Page 23
UL508A Short Circuit Current Rating (SCCR) Series rating for Siemens Breakers www.ul.com/database Series rating Tested combinations Fuse MCCB 3VL MCCB 3VL MCB 5SJ4..HG4 MCB 5SJ4..HG4 M 3RT contactor 3RB motor protection relay Page 24
UL508A Short Circuit Current Rating (SCCR) Transformer peak-let-through currents can be used to protect Branch circuits! Feeder circuit Main Disconnect Current limiting device Every Transformer is current limiting Branch circuit Short circuit protection Short circuit protection Short circuit protection contactor contactor contactor Overloadrelay Overloadrelay motor motor heater Page 25
UL508A Short Circuit Current Rating (SCCR) Page 26
UL508A Short Circuit Current Rating (SCCR) Page 27
UL508A Short Circuit Current Rating (SCCR) 1.) Single Phase Transformers: Transformer Full-Load Current (IFL) = (Transformer kva x 1000) / Voltage* Short Circuit Current (ISC line-to-line) = ((Transformer Full Load Current (IFL )) / Transformer Impedance (Z) 2.) Three Phase Transformers: Transformer Full-Load Current (IFL) = (Transformer kva x 1000) / (Voltage** x 1.732) Short Circuit Current (ISC line-to-line-to-line) = ((Transformer Full Load Current (IFL )) / Transformer Impedance (Z) Page 28
UL508A Short Circuit Current Rating (SCCR) Result: 3 Ph. 480Y/277V AC Class J Fuse, 100 Amps A.I.C: 100 ka Overall SCCR = 100kA = A.I.C of the Class J Fuse on the primary side of the Transformer since the available secondary fault current of the transformer (4.6kA) is less than the SCCR and A.I.C s of the components on the load side of the transformer Transformer: S = 150 kva, Z = 4%, 3 Phase, 480/277V Available secondary Fault Current = 4.6kA @480V Power Distribution Block SCCR: 10 ka @480V Infeed system SCCR: 65 ka @480V MCB A.I.C: 10 ka @480V MSP A.I.C: 65 ka @480V Compact MSP A.I.C: 30 ka @480V MSP s A.I.C: 65 ka @480V Solid state relay SCCR: 5 ka @480V Contactors SCCR: 5 ka @480V Terminal Block SCCR: 10 ka @480V Terminal Block SCCR: 10 ka @480V Terminal Block SCCR: 10 ka @480V Terminal Blocks SCCR: 10 ka @480V Page 29
UL508A Short Circuit Current Rating (SCCR) Use of current limiting fuses, when used as feeder elements SB 4.3.3 Only fuses listed in UL508A table SB 4.2 are applicable. Use let-through values from the UL508A table SB 4.2 ONLY (manufacturer s values are NOT permissible) Fuses are also standardized in the geometrical dimensions manufacturer-independent replacement The fuse is replaced by the service staff, which shall not compare the corresponding let-through values (old fuse versus new fuse) Note: For practical application only partially useable, as, e.g.: Standard contactor up to 37kW: max. 5kA Standard busbar: max. 10kA Standard terminal block: max. 10kA Page 30
UL508A Short Circuit Current Rating (SCCR) Use of current limiting fuses, when used as feeder elements SB 4.3.3 Use let-through values from the UL508A table SB 4.2 ONLY (manufacturer s values are NOT permissible) Fuses are also standardized in the geometrical dimensions manufacturer-independent replacement The fuse is replaced by the service staff, which shall not compare the corresponding let-through values (old fuse versus new fuse) Example: There are 7 different 30A Class R Fuses, each. with different characteristics Page 31
UL508A Short Circuit Current Rating (SCCR) Use of current limiting circuit breakers, listed as current limiting, when applied as feeder element SB 4.3.2 The circuit breaker must be listed as current limiting The circuit breaker must be marked as current limiting (UL508A SB 4.3.2) The manufacturer has to publish the current limiting characteristics or data and provide them to the user When replacing the circuit breaker by a different type or manufacturer, the SCCR value must be checked again engineering is required Note: For practical applications hardly usable, as, e.g.: Standard contactor up to 37kW: max. 5kA Standard busbar: max. 10kA Standard terminal block: max. 10kA Siemens current limiting breakers Page 32
UL508A Short Circuit Current Rating (SCCR) Siemens SIRIUS Contactor 3RT1035 Short Circuit Current 5kA, 600V Page 33
UL508A Short Circuit Current Rating (SCCR) See report in the annex Magnetic Motor Control Type F Page 34
UL508A Short Circuit Current Rating (SCCR) http://www.usa.siemens.com/sccr Page 35
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