UL-414-BULLETIN-2007=14P.pdf

FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Subject 414 November 20, 2007 SUMMARY OF TOPICS The following changes in requirements are being proposed: 1. For Preliminary Review Only: Requirements for Current Carrying Part of Potential Jaw Assembly 2. For Preliminary Review Only: Update of Conduit Trade Size in Ampacity Table 7.1 3. For Preliminary Review Only: Addition of Requirements for Anti-Rejection Clips 4. For Preliminary Review Only: Clarifi cation to Requirement for Heating Test in Paragraph 13.16 for Meter Bypass 5. For Preliminary Review Only: Inclusion of Reference to Wiring Space Requirements for Metering Transformer Cabinets in Paragraph 40.1.1 6. For Preliminary Review Only: Addition of Appendix for Explanatory Information Regarding Wire Bending Distance (Section 10) COMMENTS DUE: December 6, 2007 This proposal is for review and comment only (no ballot at this time). Please note that comments on a preliminary review document will not receive a response from the proposal author through CSDS. Instead, the proposal author will be asked to review the comments and adjust the proposals and/or supporting rationale as the author determines to be appropriate. The preliminary review process is an informal mechanism that provides authors with the opportunity to refi ne their proposals before they advance to the next stage in ULs standards development process. In some cases, the author of the proposals may choose to discontinue them. In this case, the author need not do anything after preliminary review has ended. Normally, the next step in the process is the more formal STP ballot and stakeholder review process. Only comments posted during the STP ballot and stakeholder review process will be provided with a response in CSDS. For your convenience in review, proposed additions to existing requirements are shown underlined and proposed deletions are shown lined-out. 1. For Preliminary Review Only: Requirements for Current Carrying Part of Potential Jaw Assembly BACKGROUND This proposal was discussed during the meeting of the Standards Technical Panel for Meter Mounting Equipment, STP 414, in Columbus, Ohio on April 19, 2007. Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION RATIONALE Proposal submitted by: Robert Osborne, UL Potential jaws, while technically a current carrying part, do not carry load current. STP members indicated their concern that the current carrying components of potential jaw assemblies should comply with the same constructional requirements applied to other current carrying parts to ensure accurate measurement by the watthour meter. To ensure these requirements are applied to potential jaw assemblies, a revision is proposed to specifi cally cover those parts associated with a potential jaw assembly. PROPOSAL 6.1.1 A All current-carrying part parts, including those associated with a potential jaw assembly, shall be of: a) Silver; b) A silver alloy; c) Copper; d) A copper alloy; e) Aluminum; or f) Aluminum alloy. Exception No. 1: A current-carrying part used only to bypass a meter may be plated steel if determined to be acceptable for the purpose in accordance with the Heating Test, Section 13. Exception No. 2: A plated No. 10 (4.8 mm diameter) or larger wire-binding screw or nut and stud terminal may be fabricated of iron or steel. 2. For Preliminary Review Only: Update of Conduit Trade Size in Ampacity Table 7.1 BACKGROUND This proposal was discussed during the meeting of the Standards Technical Panel for Meter Mounting Equipment, STP 414, in Columbus, Ohio on April 19, 2007. RATIONALE Proposal submitted by: Robert Osborne, UL Conduit sizes in Table 7.1 no longer match those in the National Electrical Code. As noted in Paragraph 13.4 of UL 414, the testing is conducted with rigid steel conduit. Based on footnote “a” in Table 7.1 of UL 414, conduit size is based on the use of Type THW conductors. Coordinating these values with those in Table C.8 of the 2005 Edition of the NEC results in changes for conduit sizes in multiple locations. PROPOSAL NOVEMBER 20, 2007SUBJECT 414-2- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Table 7.1 Ampacity of insulated conductors Size,Conduit trade size inches fora Temperature rating of conductor 75°C (167°F)90°C (194°F)b AWG or kcmil (mm2)3 Wires4 WiresCopperAluminumCopperAluminum 142.11/21/21520 123.31/21/220152015 105.31/21/2 3/430253025 88.43/41 3/450405545 613.31 3/4165507560 421.211-1/485c65c9575 326.71-1/4 11-1/4100c75c11085 233.61-1/41-1/4115c90c130100 142.41-1/41-1/2130c100c150115 1/053.51-1/22150c120c170135 2/067.41-1/22175c135c195150 3/085.022200c155c225175 4/0107.022-1/2230c180c260205 kcmil 2501272-1/2 22-1/2255c205c290230 3001522-1/23285c230c320255 3501772-1/23310c250c350280 4002033 2-1/23335c270c380305 50025333-1/2380c310c430350 60030433-1/2420c340c475385 7003553-1/24460375520420 7503803-1/24475385535435 8004053-1/24490395555450 9004563-1/24520425585480 100050645545445615500 125063355590485665545 150076056625520705585 175088756650545735615 2000101356665560750630 NOTES 1 For a multiple-conductor connector at a terminal, the value is to be multiplied by the number of 1/0 AWG and larger conductors that the terminal will accommodate. 2 These values of ampacity apply only if no more than three conductors will be fi eld-installed in the conduit. If four or more conductors, other than a neutral that carries the unbalanced current, will be installed in a conduit (as may occur because of the number of conduit hubs provided or because of the number of wires necessary in certain polyphase systems or for other reason), the ampacity of each of those conductors is reduced as shown in Table 7.2. a Conduit size based on use of conductors having insulation thickness comparable to that of Type THW conductors and with conduit hubs or knockouts provided in the enclosure. b A meter socket may be rated for use with conductors on the line side having 90°C (194°F) ampacity under the following conditions: 1) Tested in accordance with Exception No. 3 to 13.6, with temperature rise limits as specifi ed in 13.3. 2) Marked in accordance with 25.10.5. NOVEMBER 20, 2007SUBJECT 414-3- Table 7.1 Continued on Next Page Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Table 7.1 Continued Size,Conduit trade size inches fora Temperature rating of conductor 75°C (167°F)90°C (194°F)b AWG or kcmil (mm2)3 Wires4 WiresCopperAluminumCopperAluminum c With respect to Exception No. 4 to 13.6, equipment intended for use in a three-wire, single-phase dwelling service circuit with 75°C (167°F) rated conductors and marked in accordance with 25.3.5 may be investigated for ratings in accordance with the conductor ampacities specifi ed in Table 7.3. 3. For Preliminary Review Only: Addition of Requirements for Anti-Rejection Clips BACKGROUND This proposal was discussed during the meeting of the Standards Technical Panel for Meter Mounting Equipment, STP 414, in Columbus, Ohio on April 19, 2007. RATIONALE Proposal item submitted by: Robert Osborne, UL Alternate dimensions for one terminal on a Class 320 amp watthour meter was included in the 2004 edition of the Standard for Physical Aspects of Watthour Meters, ANSI C12.10. This alternate dimension is identifi ed in Figure 7 as a size “D” terminal. Width of this terminal is narrower than other meter terminals (0.76 inches for standard terminals versus 0.58 inches for the size “D” terminal). The use of the narrower terminal in a specifi c arrangement allows for a rejection clip to be used on the meter socket jaw that will only allow the insertion of the reduced width terminal. The rejection feature (also referred to as an “anti-inversion clip”) is inserted into the upper right hand jaw of a 320-ampere meter socket. The purpose of the clip is twofold: (1) to disallow a 200 ampere meter to inserted into the 320 ampere meter socket, and (2) restrict a 320 ampere meter from being inserted upside down. Various tests in UL 414 require the use of a simulated meter in the course of conducting the test. The dimensions for the jumper bars used in the simulated meter for a Class 320 watthour meter are detailed in Figure 13.3. These dimension are based on the standard width terminal as the fi gure specifi es a terminal width of 0.75 inches. This dimension is such that the simulated meter would be incompatible with a meter socket supplied with a rejection clip. A modifi ed simulated meter is being proposed in order to account for this new type of meter design. This simulated meter is proposed as an alternate design to be used in the evaluation of those meter sockets intended for use watthour meters constructed with the rejection feature. In addition, the reduced width provides less surface area than that of the standard width terminal, resulting in an increase in the current density of the terminal to jaw point of connection. Due to the reduction in surface area, conducting the Heating Test with the simulated meter constructed with the reduced width terminal would be considered representative of the standard width design. Acknowledging that watthour meters with the narrower profi le may be used in meter sockets without the rejection clip (which may be installed in either the factory of fi eld), this proposal includes a marking that would be required on those meter sockets that have not been evaluated for use with Class 320 watthour meters with the reduced width terminal. In addition to this new marking requirement, UL recognizes that existing products will not be so marked, and to address existing (legacy) products, NOVEMBER 20, 2007SUBJECT 414-4- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION intends to revise it Guide Card for Meter Sockets to indicate that those meter sockets not provided with or intended for use with a rejection clip to restrict the use of the full width meter terminal have not been evaluated for use with watthour meters having this rejection feature. It is proposed that testing of meter sockets intended for use with watthour meters with the reduced width terminal use the alternate design of the simulated meter. The one exception to this practice is for the Insertion and Withdrawal Force Test for Meter Jaws. In the case of this test, both types of Class 320 simulated meter (the existing design and that with the reduced width terminal) are to be used for testing, unless the meter socket is intended for use with only one type of watthour meter. PROPOSAL 13.8.1 The Class 320 simulated meter detailed in Figure 13.3 shall be supplied with the alternate size “D” terminal. Exception:Meter sockets not provided with, or intended for use with a rejection clip to restrict the use of the full width meter terminal may be evaluated using the Class 320 simulated meter with standard sized terminals. Meter sockets evaluated using the Class 320 simulated meter with standard sized terminals shall be marked in accordance with 25.13.1. This is generated text for fi gtxt. NOVEMBER 20, 2007SUBJECT 414-5- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Figure 13.3 Dimensions for jumper bars of Class 320 simulated meter NOVEMBER 20, 2007SUBJECT 414-6- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION Figure 13.3 (Cont.) CHAMFER NOTES All dimensions in inches. Multiply dimensions in inches by 25.4 to obtain millimeters. Round off to nearest 0.02 mm. Material is 0.094 ±0.002 (2.5 ±0.05 mm) by 0.750 ±0.005 inch (2.4 ±0.05 by 19.0 ±0.012 mm) round edge copper with electro-tin plate 0.0002 0.0005 inch (0.005 0.012 mm) thick. Dimension A for copper pin holes determined to suit meter base plate used. Size D terminal provided in upper right hand quadrant of simulated meter. NOVEMBER 20, 2007SUBJECT 414-7- Copyright Underwriters Laboratories Inc. Provided by IHS under license with ULLicensee=IHS Employees/1111111001, User=Japan, IHS Not for Resale, 12/17/2007 19:12:53 MSTNo reproduction or networking permitted without license from IHS -,-,- FOR INTERNAL UL OR CSDS USE ONLY NOT FOR OUTSIDE DISTRIBUTION 17.1 Five meter socket samples that have not been conditioned or lubricated shall be subjected to the insertion and withdrawal of a simulated meter used in the heating test as described in 17.3. During and after the test: a) No operation shall require a force greater than 100 pounds (445 N) and b) The base shall not fracture or become permanently deformed. Exception No. 1: A meter socket employing jaws of the release type shall be investigated in accordance with 17.2. Exception No. 2: Lubrication may be employed if usually supplied with the meter socket. Exception No. 3: A meter socket intended for use with Class 320 meters shall also be subjected to the test using the simulated meter with full width blades (no size “D” terminal) unless the meter socket is provided from the factory with a rejection clip intended to restrict the use of watthour meters with full width terminals. 25.14 Rejection clip 25.14.1 Meter sockets rated 320 Amp continuous and evaluated for use only with the Class 320 simulated meter with full width terminals (see the Exception to 13.8) shall be marked “Not Intended For Use With Class 320 A Watthour Meters With Reduced Width Terminal