ATIS 0600321-2015 Electrical Protection for Network Operator-Type Equipment Positions.pdf

1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-0600321.2015 Electrical Protection for Network Operator-Type Equipment Positions As a leading technology and solutions development organization, the Alliance for Telecommunications Industry Solutions (ATIS) brings together the top global ICT co

2、mpanies to advance the industrys most pressing business priorities. ATIS nearly 200 member companies are currently working to address the All-IP transition, network functions virtualization, big data analytics, cloud services, device solutions, emergency services, M2M, cyber security, network evolut

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5、munication Union (ITU), as well as a member of the Inter-American Telecommunication Commission (CITEL). For more information, visit www.atis.org. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other c

6、riteria for approval have been met by the standards developer. Consensus is established when, in the judgment of the ANSI Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but

7、 not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made towards their resolution. The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether he has approved t

8、he standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards. The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Mor

9、eover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standar

10、d. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive curr

11、ent information on all standards by calling or writing the American National Standards Institute. Notice of Disclaimer for sensitive areas such as the face, the threshold of perception may be 500 volts or lower. ESD protective measures are used commonly in locations where integrated circuits and oth

12、er microelectronic devices are handled. These measures are intended to keep electrostatic potentials to very low levels (less than ATIS-0600321.2015 5 10 volts). In general, the measures required to maintain ESD at levels that are comfortable for personnel can be less stringent. The control measures

13、 of clause 4 are intended to either reduce the incidence of triboelectric charging (antistatic measures) or to ensure slow charge removal (static dissipation). There are many strategies for minimizing ESD events. The following clauses list a variety of such measures, but are by no means all-inclusiv

14、e. As a rule, not all of these techniques will be either necessary or desirable to establish an ESD protected area. The appropriate ESD protection strategy should be based on the particular application and the advantages and disadvantages of each ESD protective method. 4.1 Relative Humidity Control

15、Control of the relative humidity can be an effective means for ESD mitigation because it aids static dissipation and is associated with lowered triboelectric charging. Many topical antistatics lose their effectiveness if the humidity is too low. Also, contaminants on insulative surfaces become more

16、conductive when humidity increases, a process that often lowers the resistance to ground enough to inhibit ESD. However, because this process depends on (uncontrolled) surface contamination, it should not be relied upon to provide static dissipation. Rooms containing network operator-type positions

17、should be maintained within the range of 40 to 55 percent relative humidity. Below 40 percent, ESD events are more likely. Above 55 percent, electrolytic corrosion may affect equipment performance. A possible disadvantage of relative humidity control is that improperly designed or maintained humidif

18、ication systems pose the risk of microbial contamination. 4.2 Flooring Any carpeting or floor tiles should have a resistance to ground between 106and 1010ohms when measured using the method of ESD-S7.1. Existing flooring that does not meet this requirement should be treated with a topical antistatic

19、 solution such as an antistatic floor wax. The effectiveness of antistatic solutions is temporary and varies with floor material and relative humidity. Flooring resistance should be monitored every two weeks minimum to verify conformance to the above requirement. 4.3 Chairs Chairs should be ESD prot

20、ective and have a resistance to ground of between 106and 1010ohms. Such chairs usually operate in conjunction with ESD protective flooring as described in 4.2. 4.4 Position Desktops (Work Surfaces) Areas on the desktop of operator positions that may be touched by the operator should have a resistanc

21、e to ground of between 106and 1010ohms when measured with the method of ESD S4.1. This can be accomplished by placing an appropriately sized mat under and around the keyboard. The mat should be grounded in accordance with ESD S6.1. 4.5 Antistatic Solutions Topical antistatic coatings should provide

22、a surface resistivity of between 105and 1010ohms per square when measured using the method of ESD-S11.11. Such coatings are not permanent and should be remeasured at least every two weeks to verify their performance. 4.6 Video Display Terminals When a VDT employing a cathode ray tube is switched on

23、or off, the redistribution of charge within the VDT creates powerful external electric fields. An ungrounded operator who is touching the VDT screen, or even located near the VDT, will be polarized by the electric field and can experience an increase in electrostatic potential of more than 7000 volt

24、s. This field-induced electrostatic potential can occur without any flow of charge to or from the VDT. When the operator reaches an elevated electrostatic potential, a spark can be drawn to any ATIS-0600321.2015 6 nearby metallic (or other sufficiently conductive) surface. Two strategies effectively

25、 mitigate field-induced ESDs: the use of static dissipative materials and shielding. Ungrounded operators can reduce field-induced electrostatic potentials on their bodies by touching static dissipative materials at an operator-type equipment position (see 4.2 4.5). Because static dissipative materi

26、als have surface resistivities in the range of 105to 1012ohms per square (see clause 3.1.19), the large potential difference between the operator and the material is equalized with little or no spark. However, if there is any bare metal in the work area, the possibility remains for an ungrounded ope

27、rator to experience a startling or painful ESD event. The second mitigative strategy for VDTs is electrostatic shielding. A conductive shield or enclosure can suppress the fields generated when the VDT switches on or off. Such shields can take the form of a grounded conductive bezel or conductive “a

28、nti-glare” screen coating or guard. Hand-held electric field meters can be used to obtain a qualitative estimate of the effectiveness of a shield or screen guard. VDTs may also be constructed to be electrostatically shielded. Electrostatic shielding of VDTs is covered in MPR 1990:8. 5 Building Entra

29、nce Facilities 5.1 Siting the PEF, CEF, The ground bus bar of equipment rooms serving the network operator-type equipment positions; Water fountain(s); Raised-floor support structures in at least four places, preferably at the corners of the position area. Where practical, ground bus bars, metallic

30、plumbing, metallic ventilation ducts, and other metallic objects should also be bonded to the nearest grid conductor. Figure 3: Example of bonding grid and interconnection to other equipment ATIS-0600321.2015 11 8 Voltage Limiting of Communications Conductors at Network Operator-type Equipment Posit

31、ions Voltage limiting should be present on communications conductors (telephone and data) at every network operator-type equipment position or cluster to help to minimize voltages between communications conductors and conductive surfaces. The position equipment should contain a deliberate voltage-li

32、miting capability, either inherent in the position equipment electronics or a separate protective device. When the voltage-limiting is internal to the equipment, it shall be provided between each communications conductor and the equipments ground reference (for example, the ACEG conductor in the equ

33、ipment power cord) to the PBT. For network operator-type equipment positions that do not contain an internal voltage-limiting capability, a secondary protector shall be provided between the PBT and each of the communications conductors where they appear at the position. An example of this is shown i

34、n figure 1. The grounding terminal for the secondary protector shall be connected to the PBT with a minimum 10 AWG insulated copper conductor not exceeding 1 meter (3 feet) in length. 8.1 Generic Criteria for Secondary Protectors Secondary protectors applied at a network operator-type equipment posi

35、tion shall be listed for the purpose by a nationally recognized testing laboratory. One way to determine applicable requirements for a listed secondary protector is to refer to UL 497A. The nominal limiting voltage shall not exceed 200 volts, shall be sufficiently low to coordinate with equipment di

36、electric at the network operator-type equipment position, and shall not interfere with normal signaling and function. 9 Voltage Limiting of ac Power Conductors at Network Operator-type Equipment Positions Voltage limiting should be present on ac power conductors at every network operator-type equipm

37、ent position or cluster to help to minimize voltages between phase and neutral conductors and the ACEG. The position equipment should contain a deliberate voltage limiting capability for the ac power input, either inherent in the position equipment electronics or as a separate external Surge Protect

38、ive Device (SPD). When the voltage limiting is internal to the equipment, it should be provided between each combination of phase and neutral conductors and the ACEG. For network operator-type equipment positions that do not contain an internal voltage-limiting capability for the ac power input, an

39、external SPD should be provided between phase and neutral conductors and the ACEG where these conductors appear at the position. An example of this is shown in figure 1. Where the external SPD is equipped with an external grounding terminal, the external grounding terminal shall be connected to the

40、PBT with a minimum 10 AWG insulated copper conductor run as short and straight as practicable and not exceeding 1 meter (3 feet) in length. Refer to clause on Surge Reference Equalizers in IEEE Standard 1100 for additional information. 9.1 Generic Criteria for Surge Protective Devices (SPD) External

41、 SPDs applied at a network operator-type equipment position shall be listed for the purpose by a nationally recognized testing laboratory, at a minimum, in accordance with UL 1449. The limiting voltage shall be in accordance with the applicable location category as defined in IEEE C62.41. The SPD sh

42、all coordinate with upstream surge protective devices. The limiting voltage shall not interfere with normal powering functions, including uninterruptable power supplies or other power conditioning units. 10 Multi-port (Multi-service) Surge Protective Device Multi-port (Multi-service) Surge Protectiv

43、e Device (MSPD) can provide external SPDs for communications and power circuits as well as the functionality of PBT as discussed in Sections 8 and 9 and shown in Figure 1 in a common enclosure. The MSPD shall be listed. ATIS-0600321.2015 12 All communication and power cables serving the protected eq

44、uipment are routed via the MSPD, which provides a common terminal for equipotential bonding (i.e., PBT) within its enclosure. Therefore, the MSPD will minimize the grounding conductors that connect the grounding terminal of SPDs to PBT and can be as long as 1 m in length (see Sections 8 and 9). Cabl

45、es from the one or more telecommunication circuits enter the MSPD at ports designated input, while protected equipment is connected to ports designated as equipment or output. The conductor separation requirements of NFPA 70 shall be observed. The functionalities of MSPD will help minimize the effec

46、ts of a surge that may appear at one of the input ports of the MSPD, does not result in an excessive coupled surge on the output ports of the MSPD. Clause 8.14 of IEEE C62.36-2000 provides a multi-port coupling test to verify that MSPD minimizes the coupled surge. In addition, IEEE draft standards,

47、PC62.50-2012 and PC62.51, are currently being developed to provide performance criteria and test methods for plug-in and hard-wire MSPDs. ATIS-0600321.2015 13 Annex A: Bibliography (informative) IEEE 1100-1999, IEEE Recommended practice for Powering and grounding sensitive electronic equipment 2ESD-

48、ADV1.0-2003, ESD Association Advisory Glossary of Terms 5ATIS-0600333.2007, Grounding and Bonding of Telecommunications Equipment. 4ANSI-J-STD-607-A-2002 Joint Standard Commercial Building Grounding (Earthing) And Bonding Requirements For Telecommunications 9TIA942-2004 Telecommunications Infrastruc

49、ture Standard for Data Centers 9IEEE C62.36-2000 IEEE standard test methods for surge protectors used in low-voltage data, communications, and signaling circuits 2IEEE PC62.50-2012 Draft Standard for Performance Criteria and Test Methods of Plug-in Multiport (Multiservice) Surge-Protective Devices for Equipment Connected to 120/240 V Single Phase Power Service and Communications Lines 2IEEE PC62.51 Draft Standard for Performance Criteria and Test Methods of Hardwire Multiport (Multiservice) Surge-Protective Devices for Equipment Connected to 120/240 V Single Phase Power Servic