Background Statement for SEMI Draft Document #4773 Line ...downloads.semi.org/web/wstdsbal.nsf/0/33aa57b9e2a7bd6288257705005... · b. Short circuit ... IEC 60204-1 (2005), Clause

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Background Statement for SEMI Draft Document #4773 Line Item Revisions to SEMI S22, Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment Revisions related to Short Circuit Current Ratings

NOTICE: This background statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this document.

NOTICE: Recipients of this document are invited to submit, with their comments, notification of any relevant patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this context, “patented technology” is defined as technology for which a patent has issued or has been applied for. In the latter case, only publicly available information on the contents of the patent application is to be provided.

NOTICE: The Safety Checklist for this document will be reviewed and voted on at the committee meeting where the document is adjudicated.

Dear Colleagues,

Several industry standards require the electrical nameplate of an industrial control panel to include a short circuit current rating (SCCR). For example:

NFPA 70-2008, Article 670.3 (A) - Permanent Nameplate. The nameplate shall include the following information: (4) Short circuit current rating of the machine industrial control panel based on one of the following: a. Short circuit current rating of a listed and labeled machine control enclosure or assembly b. Short circuit current rating established utilizing an approved method.

NFPA 70-2008, Article 409.110 - Marking. An industrial control panel shall be marked with the following information that is plainly visible after installation: (3) 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 machine control enclosure or assembly b. Short circuit current rating established utilizing an approved method.

NFPA 79-2007, Section 16.4.1 - Machine Nameplate Data. A nameplate giving the following information shall be attached to the enclosure: (6) Short-circuit current rating of the control panel.

UL 508A, Industrial Control Panel, First Edition, April 25, 2001 (revised through May 1, 2003) 52.1 An industrial control panel shall be provided with a nameplate that includes the following: b) Complete electrical rating of each source of supply as specified in 49.1 49.5 The input terminals in 49.1 shall have a short circuit current rating. The short circuit rating shall be based on the requirements in Supplement SB. (Effective April 25, 2006).

SEMI S2-0709, Section 13.4.12 – A permanent nameplate listing the manufacturer’s name, machine serial number, supply voltage, phase frequency, short circuit current rating of the equipment or its industrial control panel and…

SEMI S22-0709, Section 20.4 i) – Equipment Nameplate – A permanent nameplate should be attached to the main electrical enclosure or equipment where it is plainly visible after installation. This nameplate should include the following information: i) short-circuit current rating of the equipment or its industrial control panel…

IEC 60204-1 (2005), Clause 16.4 - Marking of equipment. Equipment (for example controlgear assemblies) shall be legibly and durably marked in a way that is plainly visible after the equipment is installed. A nameplate giving the following information shall be attached to the enclosure adjacent to each incoming supply: ... short-circuit rating of the equipment; …

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IEC 60204-33 (2009), Clause 16.4 – Equipment nameplate. A permanent nameplate should be attached to the main electrical enclosure of the fabrication equipment where it is plainly visible after installation. This nameplate shall include the following information: (i) short-circuit rating of the electrical equipment connected to each incoming supply.

These standards establish the requirement for an SCCR to be printed on the nameplate of a machine or its industrial control panel, and for the SCCR to be established utilizing an approved method; however, the standards do not establish what level of SCCR is acceptable, or not acceptable.

Since the introduction of these SCCR requirements, compliance with NFPA 70-2008, Article 110.10, has become increasingly difficult. This code requires the SCCR of the circuit components to be selected to permit the circuit-protective devices to clear a fault without extensive damage to the electrical components of the circuit. This presents a challenge for facilities engineers as the available fault currents at many semiconductor manufacturing facilities exceed the SCCR rating of many pieces of semiconductor equipment. As a result, equipment installations at facilities have been affected.

In an effort to help address this challenge, the semiconductor industry expressed an interest to develop and publish a table containing a set of available fault currents, at various voltages and full load currents, at a ‘typical’ end-use facility based on a set of ‘typical’ parameters. The goal of this table is to provide equipment suppliers and the end-users with a reasonable target values towards which to strive, both from the perspective of limiting the amount of available fault current at the facilities level, as well as increasing the SCCR of the equipment or its industrial control panel.

The table presented in this ballot is based on the available fault current calculations of a typical electrical distribution system in a typical semiconductor manufacturing facility. The assumptions used and a graphical representation of the typical facility and its 3-phase available fault currents are included in the proposed text,

The proposed RI includes a table that summarizes the typical maximum available fault currents in the described facility.

This ballot consists of one Line Item for implementation to the referenced SEMI document. The Line Item proposes including Table-1 in SEMI S22 as a means of documenting the available fault current at a typical facilities. Equipment with a lower short circuit current rating than the available fault current may be prevented from being installed at a facility.

This Line Item consists of two parts:

LI1, Part A: Revise Note 12 in Section 5.1.66 of SEMI S22 to include reference to Related Information 3 suggesting ‘reasonable’ target values for facilities’ available fault current and short circuit current rating of equipment or its industrial control panel.

LI1, Part B: Add Related Information 3 to SEMI S22 with Table-1 Available Fault Current.

This ballot has not been prepared in Delayed Revision format and you are entitled to reject this Line Item based on its effectivity being immediate upon publication, should it pass. Please also review the technical substance of this Line Item. If you chose to reject this line item for any reason (i.e., effectivity or technical content), include in your Reject vote (as required by SEMI regulations) any negative argument about the technical substance or effectivity that you consider grounds for rejection.

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Review and Adjudication Information

Task Force Review Committee Adjudication Group: Short Circuit Current Rating Task Force North America EHS Committee Date: TBD (will be held during the week of

SEMICON West 2010: 12-16 July 2010) Friday 16 July 2010

Time & Timezone: TBD 0800-1700 PDT Location: San Francisco Marriott San Francisco Marriott City, State/Country: San Francisco, CA San Francisco, CA Leader(s): Eric Sklar (Safety Guru, LLC)

Chris Evanston (Salus) Sean Larsen (AMEC) Eric Sklar (Safety Guru, LLC) James Beasley

Standards Staff: Ian McLeod (SEMI NA) 408.943.6996 [email protected]

Ian McLeod (SEMI NA) 408.943.6996 [email protected]

This meeting’s details are subject to change, and additional review sessions may be scheduled if necessary. Contact the task force leaders or Standards staff for confirmation.

Telephone and web information will be distributed to interested parties as the meeting date approaches. If you will not be able to attend these meetings in person but would like to participate by telephone/web, please contact Standards staff.

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Safety Checklist for SEMI Draft Document #4773 Line Item Revisions to SEMI S22, Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment Revisions related to Short Circuit Current Ratings

Developing/Revising Body Name/Type: SCCR Task Force Technical Committee: EHS, FPD Region: NA Leadership

Position Last First Affiliation Leader Karl Edward Applied Materials Author/Editor* Bryan Matt Intel Corporation Editor* Sklar Eric SafetyGuru

Documents, Conflicts, and Consideration Safety related codes, standards, and practices used in developing the safety guideline, and the manner in which each item was considered by the technical committee

# and Title Manner in Which the Standards was Considered in This Safety Guideline

UL 508A, Industrial Control Panels Reviewed the procedure for determining SCCR of Industrial Control Panels, as specified in Supplement SB.

Cooper Bussmann, Bulletin EPR-1, http://www.bussmann.com/library/docs/EPR_Booklet.pdf

Reviewed the point-to-point method for determining SCCR from one end of a conductor to another, as well as SCCR of transformer output.

NFPA 79-2007, Electrical Standard for Industrial Machinery 2007 Edition

Reviewed the criteria for SCCR.

NFPA 70, National Electrical Code Reviewed the criteria for SCCR in Articles 670.3(A) and Article 409.110.

SEMI S2, Environmental, Health, and Safety Guideline For Semiconductor Manufacturing Equipment


SEMI S22, Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment


SEMI S26, Environmental, Health, and Safety Guideline for FPD Manufacturing Equipment


IEC 60204-1 Safety of Machinery – Electrical Equipment of Machines, Part 1

Reviewed the criteria for short-circuit rating.

IEC 60204-33 Safety of Machinery – Electrical Equipment of machines, Part 33: Requirements for Semiconductor Fabrication Equipment

Reviewed the criteria for short-circuit rating.

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Known inconsistencies between the safety guideline and any other safety related codes, standards, and practices cited in the safety guideline # and Title Inconsistency with This Safety Guideline None Other conflicts with known codes, standards, and practices or with commonly accepted safety and health principles to the extent practical # and Title Known Conflicts with this Safety Guideline None

Participants and Contributors

Last First Company Email Karl Edward Applied Materials [email protected] Bryan Matt Intel Corporation [email protected] Crockett Alan KLA-Tencor [email protected] Wong Carl AKT America, Inc. [email protected]

Guild Ed IBM Corporation [email protected] Rehder Alan Underwriters Laboratories [email protected] Petry Bill IBM Corporation [email protected] Roberge Steve Axcelis [email protected] Greenberg Cliff Nikon Precisions [email protected] Kapur Ken KLA-Tencor [email protected] Palmero Edwin Applied Materials [email protected] Sigmund Peter Applied Materials [email protected] Krov Alan Tokyo Electron of America [email protected] Sklar Eric Safety Guru [email protected] Kennis Debbie Semitool [email protected] Kryska Paul Novellus [email protected]

The content requirements of this checklist are documented in Section 14.2 of the Regulations Governing SEMI Standards Committees.

This is a draft document of the SEMI International Standards program. No material on this page is to be construed as an official or adopted standard. Permission is granted to reproduce and/or distribute this document, in whole or in part, only within the scope of SEMI International Standards committee (document development) activity. All other reproduction and/or distribution without the prior written consent of SEMI is prohibited.

Page 1 Doc. 4773 SEMI

Semiconductor Equipment and Materials International 3081 Zanker Road San Jose, CA 95134-2127 Phone:408.943.6900 Fax: 408.943.7943

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DRAFTDocument Number: 4773

Date: 2010/04/16

SEMI Draft Document #4773 Line Item Revisions to SEMI S22, Safety Guideline for the Electrical Design of Semiconductor Manufacturing Equipment Revisions related to Short Circuit Current Ratings

Line Item 1, Part A: Revise Note 12 in Section 5.1.66 of SEMI S22 to include reference to Related Information 3 defining the available fault current at a typical facility. Text to be removed is shown struck through; text to be added is shown underlined. Only the text that is struck through or underlined is proposed to be changed by this Line Item.

5.1.66 short circuit current rating — the maximum prospective available current to which an equipment supply circuit is intended, by the equipment manufacturer, to be connected.

NOTE 12: Short circuit current rating for an electrical system is typically based on the analysis of short circuit current ratings of the components within the system. See UL 508A and Related Information 2 for methods which may be used to determine short circuit current rating. Related Information 3 describes the available fault current at given piece of equipment in a typical semiconductor facility to be considered during semiconductor equipment and semiconductor facility design.




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Line Item 1, Part B: Add Related Information 3 to SEMI S22 with Available Fault Currents for Different Nominal Voltages and Full Load Current at a Typical Facility. The following text is proposed to be added as Related Information 3 to SEMI S22. For ease of reading, it has *not* been underlined. RELATED INFORMATION 3 – Available Fault Currents for Different Nominal Voltages and Full Load Currents at a Typical Facility. NOTICE: This related information is not an official part of SEMI S22 and was derived from the work of the global Environmental, Health & Safety Committee. This related information was approved for publication by full letter ballot.

R3-1 Introduction

R3-1.1 While there are a number of product safety standards specifying short circuit current rating of the equipment or its industrial control panel to be included on the equipment nameplate, they offer no guidance in terms of reasonable target values towards which equipment designers should strive. As a result, end-users of the equipment are often faced with the challenge of installing equipment which has a lower short circuit current rating than the available fault current from the facilities. In an effort to address this challenge, the industry developed a set of descriptions of available fault current values that are likely to exist in a “typical” end-use facility.

R3-1.2 Table-R3-1 describes the available fault currents at the facility points of connection terminals for equipment in a typical semiconductor facility based on the equipment's nominal voltage and maximum full load amperes ratings. This information is provided for consideration in designing semiconductor facilities and semiconductor equipment. The installation challenges described above will be reduced if facility designers strive not to exceed these values and equipment designers strive to meet or exceed these values.

R3-1.3 The following assumptions were used to establish the typical electrical distribution system in a semiconductor manufacturing facility, based on IEEE and ANSI Standards (e.g., IEEE Standard 551 for Calculating Short Circuit Currents in Industrial and Commercial Power Systems, IEEE Standard 141 for Electric Power Distribution for Industrial Plants, IEEE Standard 399 for Power System Analysis, ANSI C37.010 for Application Guide for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis), as implemented by commercially available software (e.g., EasyPower®). See Figure R3-1 for a graphical representation of this system showing its components and available fault currents.

1. Infinite utility source at the primary of a 12.5kV to 480V transformer 2. 2500kVA, 7% Z, 12.5kV-480V transformer 3. 3.48 m (10 ft) of 4000A bus from the transformer secondary to the 480V switchgear 4. 7.62 m (25 ft) of wire from the 480V switchgear to a 480V 1200A distribution board 5. 7.62 m (25 ft) of wire from the 480V distribution board to the primary of a 480V-208V transformer 6. 300kVA, 4%Z, 480V-208V transformer 7. 7.62 m (25 ft) of wire from the transformer secondary to a 208V 1000A distribution board 8. 3.48 m (10 ft) of wire from the 208V distribution board to a 208V 200A panel board 9. 12.19 m (40 ft) of wire from the 480V distribution board to 480V equipment with FLA 16A thru 640A 10. 12.19 m (40 ft) of wire from the 208V distribution board to 208V equipment with FLA 64A thru 320A 11. 12.19 m (40 ft) of wire from the 208V panel board 208V equipment with FLA 16A thru 56A 12. All wires sized based on the 75 deg C ampacity rating for copper conductor




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Figure R3-1: Graphical Representation of Typical Facility and its 3 Phase Fault Current




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Table R1-1 Available Fault Current for equipment with nominal voltages and maximum rated equipment full load current (FLA).

Available Fault Current [kA]

Max Rated Equipment Full Load Current (FLA)

Nominal Voltage#1

120 V Nominal Voltage#1

208 V Nominal Voltage#1

480 V

16 1 2 4

24 2 2 6

32 3 4 9

40 3 4 9

48 4 5 13

56 5 7 19

64 7 19

72 8 21

80 8 21

88 9 24

100 10 26

120 11 28

140 11 29

160 12 30

180 12 31

200 12 32

240 13 32

280 13 33

320 14 35

360 14 36

400 14 36

480 14 36

560 14 37

640 14 37

#1Voltages expressed represent nominal U.S. voltages. The closest corresponding nominal voltage(s) could be used for non-U.S. power systems.

NOTICE: SEMI makes no warranties or representations as to the suitability of the safety guideline(s) set forth herein for any particular application. The determination of the suitability of the safety guideline(s) is solely the responsibility of the user. Users are cautioned to refer to manufacturer’s instructions, product labels, product data sheets, and other relevant literature respecting any materials or equipment mentioned herein. These safety guidelines are subject to change without notice.

By publication of this safety guideline, Semiconductor Equipment and Materials International (SEMI) takes no position respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this safety guideline. Users of this safety guideline are expressly advised that determination of any such patent rights or copyrights, and the risk of infringement of such rights are entirely their own responsibility.