Related Manuals for Siemens NEC Article 409
Summary of Contents for Siemens NEC Article 409
- Page 1 Industrial Controls Short-circuit current rating (SCCR) of industrial control panels Reference Manual Edition 06/2013 Answers for industry.
- Page 3 ___________________ Overview of NEC Article 409 Overview of Supplement SB ___________________ from the UL 508A standard NEC Article 409 and UL 508A Basic steps for calculating ___________________ the SCCR of a control panel Flow chart for calculating the ___________________...
- Page 4 Note the following: WARNING Siemens products may only be used for the applications described in the catalog and in the relevant technical documentation. If products and components from other manufacturers are used, these must be recommended or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and maintenance are required to ensure that the products operate safely and without any problems.
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Page 5: Table Of Contents
Table of contents Introduction ............................. 7 Overview of NEC Article 409 ........................9 Overview of Supplement SB from the UL 508A standard ............... 11 Basic steps for calculating the SCCR of a control panel ................. 13 SB4.2 – Determining the short-circuit current ratings (SCCR) of individual power circuit components .......................... - Page 6 Table of contents Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 7: Introduction
● Design and marking of panels ● Correct installation and modification of control panels Siemens is committed to supplying best-in-class products and services to our customers. Siemens provides extensive product documentation to enable its customers to comply with NEC Article 409 and the UL 508A standard. - Page 8 Introduction Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 9: Overview Of Nec Article 409
Overview of NEC Article 409 The "NFPA 70: National Electrical Code" includes "Article 409" on the Construction of Industrial Control Panels operating at 600 volts or less. Section 409.2: definition of industrial control panels Section 409.2 defines an industrial control panel as: "An assembly of two or more components consisting of one of the following:... - Page 10 Overview of NEC Article 409 Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 11: Overview Of Supplement Sb From The Ul 508A Standard
Components in the power circuit UL508A is the safety standard for industrial control panels. NEC Article 409 references UL508A Supplement SB as an approved method for determining the SCCR of an industrial control panel. The specific method is outlined in Section SB4. - Page 12 Overview of Supplement SB from the UL 508A standard Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 13: Basic Steps For Calculating The Sccr Of A Control Panel
Exception The short-circuit current rating of Siemens frequency converters is stated in the operating instructions or the relevant catalogs. This complies with the requirements of NEC Article 409 and is therefore entered in the relevant UL test reports. Moreover, in the case of frequency converters that are protected with fuses, circuit breakers... -
Page 14: Basic: Assumed Short-Circuit Current Rating
Basic steps for calculating the SCCR of a control panel 4.1 SB4.2 – Determining the short-circuit current ratings (SCCR) of individual power circuit components 4.1.2 Basic: Assumed short-circuit current rating For unmarked components, the assumed maximum short-circuit current rating in accordance with Table SB4.1 (see extract) can be used for calculating the short-circuit current rating. - Page 15 4.1 SB4.2 – Determining the short-circuit current ratings (SCCR) of individual power circuit components Download: certificates of compliance Certificates of Compliance (http://www.siemens.com/sirius/support) for switching devices can be downloaded on the Internet. These contain the contents of the UL test reports that are relevant for configuration.
- Page 16 Support: certificate download 3 Figure 4-7 Support: certificate download 4 General information and relevant product documentation (including configuration manuals) relating to North America are also available on the Internet (www.siemens.com/applicationconsulting/ul). Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
- Page 17 Basic steps for calculating the SCCR of a control panel 4.1 SB4.2 – Determining the short-circuit current ratings (SCCR) of individual power circuit components Example The following example shows a circuit breaker according to UL489 in a feeder circuit and a tested combination according to UL508 Type F.
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Page 18: Sb4.3 - Adaptation Of The Available Short-Circuit Current Rating Based On The Peak Let-Through Currents When Using Current-Limiting Devices In The Feeder Circuit
Basic steps for calculating the SCCR of a control panel 4.2 SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit When short-circuit-current-limiting components are used in the feeder circuit, all components... - Page 19 Basic steps for calculating the SCCR of a control panel 4.2 SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit The selected circuit breaker lets 22 kA through at a short-circuit of 100 kA.
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Page 20: Current-Limiting Fuses
Basic steps for calculating the SCCR of a control panel 4.2 SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit 4.2.3 Current-limiting fuses Only fuses from UL508A, Tab. SB4.2 may be used as current-limiting fuses. This table shows the relevant peak let-through currents (see column I x 10³). - Page 21 Basic steps for calculating the SCCR of a control panel 4.2 SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit Examples The following two examples show a fuse as the feeder circuit protective device. The procedure described also applies if a circuit breaker according to UL489 is used as the feeder circuit protective device.
- Page 22 Basic steps for calculating the SCCR of a control panel 4.2 SB4.3 – Adaptation of the available short-circuit current rating based on the peak let-through currents when using current-limiting devices in the feeder circuit Example 2 ⇒ SCCR 50 kA since the breaking capacity of the circuit breaker is not lower than that of the fuse.
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Page 23: Sb4.4 - Sccr Calculation Of The Industrial Control Panel
Basic steps for calculating the SCCR of a control panel 4.3 SB4.4 – SCCR calculation of the industrial control panel SB4.4 – SCCR calculation of the industrial control panel The SCCR of the industrial control panel is calculated with limitation to the lowest value of a component or a circuit according to SB4.2 or SB4.3. - Page 24 Basic steps for calculating the SCCR of a control panel 4.3 SB4.4 – SCCR calculation of the industrial control panel Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 25: Flow Chart For Calculating The Sccr Of A Component
Flow chart for calculating the SCCR of a component Calculation of the short-circuit current rating of an individual power circuit component according to UL 508A SB4.2 Figure 5-1 SB4.2 Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001... -
Page 26: Calculation Of The Short-Circuit Current Rating Of Current-Limiting Feeder Components
Flow chart for calculating the SCCR of a component 5.2 Calculation of the short-circuit current rating of current-limiting feeder components Calculation of the short-circuit current rating of current-limiting feeder components Figure 5-2 SB4.3 (1) Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001... - Page 27 Flow chart for calculating the SCCR of a component 5.2 Calculation of the short-circuit current rating of current-limiting feeder components Figure 5-3 SB4.3 (2) Short-circuit current rating (SCCR) of industrial control panels Reference Manual, 06/2013, A5E31896849002A/RS-AA/001...
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Page 28: Calculation Of The Short-Circuit Current Rating Of A Control Panel In Accordance With Ul 508A Supplement Sb 4.4
Flow chart for calculating the SCCR of a component 5.3 Calculation of the short-circuit current rating of a control panel in accordance with UL 508A Supplement SB Calculation of the short-circuit current rating of a control panel in accordance with UL 508A Supplement SB 4.4 Figure 5-4 SB4.4 Short-circuit current rating (SCCR) of industrial control panels... - Page 30 Contact for all technical information: Technical Assistance Tel.: +49 (911) 895-5900 e-mail: technical-assistance@siemens.com www.siemens.com/sirius/technical-assistance Siemens AG Subject to change without prior notice Industry Sector Order No.: A5E31896849002 Postfach 23 55 90713 FUERTH © Siemens AG 2013 GERMANY Industrial Controls SIRIUS www.siemens.com/automation...