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1、Subject 67 (98, 869A, 891, 977, 1429) November 23, 2005 SUMMARY OF TOPICS The following topics were discussed at the meeting: 1. Alignment of Ratings/Overload/Endurance Tables (UL 98 and UL 1429) 2. Development of Requirements for Power Distribution Equipment to be Used in Solar Photovoltaic Systems
2、 (All Standards) 3. Horsepower rated General-Use and Motor-Circuit Switch Test Parameters for Endurance Test (UL 98) 4. Marking Limitations for Motor-Circuit Switches (UL 98) 5. Clarification of Testing Requirements for Motor-Circuit Switches (UL 98) 6. Other Non-STP Business: Development of Categor
3、y for Listed Panelboard and Switchboard Accessories. (UL 67 and 891) 7. Suitability of Existing Requirements for “Separation for Class 2 and Class 3 Circuits“ (UL 67) 8. On-Off Position of Switch Handles (All Standards) 9. Screws Intended for Field Tightening and Located in the Back of Enclosures (U
4、L 98) IO. Updating of Ground-Fault Protection Requirements to Address use of Rating Plugs (UL 891 and 67) I I . Surface Mounted vs. Flush Mounted Enclosed Panelboards 12. Open Bottom Panelboard Enclosures 13. Operating Handle Positioning (UL 98) 14. Minimum Spacings (UL 98) 15. Transfer Switches (UL
5、 67, UL 98) 16. Discussion of Comments Received for UL 67 Proposal Bulletin Dated July 15, 2005 17. Agenda Items Requested by Tim Crnko, Cooper Bussman (UL 67, UL 98, UL 869A, UL 891, UL 977) 18. Insulation Material Requirements for Enclosed and Dead-Front Switches (UL 98) SUBJECT 67 -2- NOVEMBER 23
6、,2005 COMMENTS DUE: December 23,2005 A meeting of the Standards Technical Panel of UL for Power Distribution Equipment, STP 67, was held on November 2, 2005 at ULs Research Triangle Park office. The purpose of the meeting was to discuss potential proposals and other issues related to power distribut
7、ion equipment covered by the STP 67 standards. The Agenda for the November 2, 2005 STP meeting contains the discussion items that were the primary focus of the meeting. The STP 67 recommendations for each of these topics are included in this Meeting Report. The following report is not intended to be
8、 a verbatim transcript of the discussions at the meeting but is intended to record the significant features of those discussions. CALL TO ORDER Mr. Bradley Schmidt, the Chairman for STP 67, called the meeting to order at 8:OO AM. The Chairman welcomed the STP members and guests and then asked everyo
9、ne to introduce themselves. The Chairman indicated that the purpose of the meeting was to discuss each of the proposals and discussion items on the agenda. The Chairman explained that the author of the proposal would present each proposal. The STP would then have the opportunity to comment on the pr
10、oposal. After this discussion, the author of the proposal may modify, withdraw, or proceed unchanged with his proposal. When necessary, proposals would be assigned to a Working Group for further development. REPORTS ON TASK GROUPS There are no Task Groups formed at this time. DISCUSSION OF PROPOSALS
11、 1. Alignment of RatingslOverloadlEndurance Tables (UL 98 and UL 1429) MEETING DISCUSSION Test parameter values have been updated in both UL 98 and UL 1429 to match those in the NEC. Based on these updates, there are instances where values exist in one of the test parameter tables, but not the other
12、 (example: 480V, 50 HP, 1 phase has an Endurance Test current of 108 A (UL 98, Table 20) but the same rating does not have a test current tabulated for the Overload Test (UL 98, Table 17); in fact, a discrepancy exists for HP ratings from 15 to 50 HP in this particular column). Another discrepancy e
13、xists in the above example in that the rating table (UL 98, Table 26) includes a rating of 50 HP for a 480 V switch (with 200 A fuseholders). As demonstrated above, no test parameters are provided for the required Overload Test. The STP provided input and suggested revising the affected tables to en
14、sure that: (1) if values appear in either the overload or the endurance table that a complete set of test parameters exist, and (2) test parameters align with requirements in both the NEC and the Canadian Electrical Code (CEC). UL will develop the proposal(s), accordingly, and present this informati
15、on to the Technical Harmonization Committee for UL 98 for review and recommendations. SUBJECT 67 -3- NOVEMBER 23,2005 2. Development of Requirements for Power Distribution Equipment to be Used in Solar Photovoltaic Systems (All Standards) MEETING DISCUSSION Requests have been received to evaluate po
16、wer distribution equipment for use in solar photovoltaic applications (ref. NEC Article 690). After discussion by the STP, it was determined that UL would explore whether there is an emerging need for developing applicable requirements for equipment intended for use in such applications. To begin th
17、is process, Dan Neeser of Cooper Bussmann and Robert Osborne of UL agreed to identify individuals within the alternate energy industry and solicit their input regarding this issue. 3. Horsepower rated General-Use and Motor-Circuit Switch Test Parameters for Endurance Test (UL 98) MEETING DISCUSSION
18、It has been suggested that a proposal be developed to clarify paragraph 7.4.2 so it is clear as to the power factor, number of operations and rate of operations that is to be used for HP rated switches. UL supports development of a proposal to modify paragraph 7.4.2 so that it presents the test para
19、meters in the format used in paragraph 7.4.1. The STP expressed general support for developing a proposal that will not change requirements, but improve the usability by using uniform wording. UL will finalize the proposal and present it for review by the Technical Harmonization Committee for UL 98.
20、 UL did present text for consideration that will serve as the starting point for this proposal. It was also noted that, based on conclusions drawn from Agenda Item 5, the editorial changes to 7.4.2 may be combined with substantial changes to requirements for “motor-circuit switches”. 4. Marking Limi
21、tations for Motor-Circuit Switches (UL 98) MEETING DISCUSSION It is noted that UL 98 identifies Motor-Circuit Switches as devices which are to be marked with horsepower ratings and not carry markings indicative of other uses (reference UL 98, paragraph 9.2.3). NEC Section 430.1 09(A)(1) identifies a
22、 “listed motor-circuit switch rated in horsepower” as a type device suitable for use as a motor disconnecting means. This Code requirement raised the question of whether or not a UL 98 switch used in this application shall be a switch marked “Motor-Circuit Switches” (.e., a switch not eligible to be
23、ar markings indicative of other uses). UL solicited the STPs opinion in SUBJECT 67 -4- NOVEMBER 23,2005 this matter, and the STP indicated their support to propose changes to UL 98 that will allow “Motor- Circuit Switches” to include ratings other than horsepower. This discussion was conducted in co
24、njunction with a discussion of Agenda Topic 5, as that topic had relevance with this topic. UL will develop a proposal to clarify that “Motor-Circuit Switches” are switches rated in horsepower. This proposal will be developed in conjunction with a proposal to address comments received in response to
25、 Agenda Item 5. Proposals will be presented to the Technical Harmonization Committee for UL 98 for review and recommendations. UL will also consider revising the Guide Card information, accordingly. 5. Clarification of Testing Requirements for Motor-Circuit Switches (UL 98) MEETING DISCUSSION Presen
26、t requirements in UL 98 specify that test currents for Motor-Circuit Switches are to be determined as follows: Heating Test: The switch is to carry continuously a current of 11 5 percent of the maximum full-load current rating as noted in paragraph 8.2.2 (paragraph 7.2.1 (c). Based on paragraph 8.2.
27、2, the maximum full-load current rating of a fused motor-circuit switch shall be the whole number nearest to 125 percent of the appropriate value selected from Table 20 or Table 21. In contrast, a General-Use switch with a horsepower rating is tested using a continuous current of 11 5 percent of the
28、 current noted in Table 20 or 21. The result is that the test current for a “Motor-Circuit Switch” is 125 percent higher than the test current for a General-Use switch with identical horsepower ratings. Overload Test: No differences are noted for testing of General-Use switches with horsepower ratin
29、gs and Motor-Circuit Switches. Endurance Test: The switch is to be tested at 125 percent of the appropriate full-load motor-running current as noted in Tables 20 or 21 (reference paragraph 7.4.2). In contrast, a General-Use switch with a horsepower rating is tested at 100 percent of the appropriate
30、full-load motor-running current as noted in Table 20 or 21. The result is that the test current for a “Motor-Circuit Switch” is 125 percent higher than the test current for a General-Use switch with identical horsepower ratings. It was noted that this issue is related to the discussion in Agenda Ite
31、m 4. STP members agreed that there should be no difference between the test requirements to achieve the same horsepower rating for a switch marked “Motor-Circuit Switch” and a switch marked for both general use and horsepower ratings. UL agreed to develop a proposal to identify one set of test param
32、eters to cover horsepower ratings, regardless of markings indicating a “motor-circuit switch”. This proposal will be presented to the Technical Harmonization Committee for UL 98 for review and consideration. SUBJECT 67 -5- NOVEMBER 23,2005 6. Other Non-STP Business: Development of Category for Liste
33、d Panelboard and Switchboard Accessories. (UL 67 and 891) MEETING DISCUSSION Currently, accessories intended for field installation in panelboards and switchboards are covered under the component recognition category for Component-Panelboard and Switchboard Accessories (QEUY2). UL has considered est
34、ablishing a new Listing category into which such products would be moved. As this was not an STP related issue, the STP Chairman recessed the STP meeting in order to allow time for this item to be discussed by those STP members with interest in the issue. The STP members decided that there was not a
35、 reason to pursue further action. 7. Suitability of Existing Requirements for “Separation for Class 2 and Class 3 Circuits (UL 67) MEETING DISCUSSION Section 18A of the Standard for Panelboards, UL 67, provides requirements for ”Separation for Class 2 and Class 3 Circuits”. Paragraph 18A.3(c) allows
36、 field-installed and factory-installed conductors, either of which, but not both, are Class 2 or 3, to be intermixed in a panelboard as long as all are insulated for the maximum voltage of either. A concern had been raised suggesting that this requirement may be in conflict with requirements of NEC
37、Article 725, as it does not appear to have an allowance for intermixing as noted in the standard. It was also noted that the UL Standard for Dead-Front Switchboards, UL 891, does not include such an allowance (reference Section 26 in the tenth edition, Section 8.7.2 of the eleventh edition). One pot
38、ential explanation for the allowance is that field installed wiring coming into a panelboard is to be considered ”an integral part of” the panelboard (making Article 725 not applicable.) But, that would seem to be open to different interpretations by AHJs. The STP requested that UL examine the stand
39、ards covered by STP 67 and develop a harmonized set of requirements that comply with the NEC. Once the proposal is developed, UL will present this information to the STP for review prior to balloting. 8. On-Off Position of Switch Handles (All Standards) MEETING DISCUSSION The various standards cover
40、ed under STP 67 have inconsistent requirements for position of switch handles. Specifically, UL is looking to harmonize requirements within these standards as they relate to the switch handle positions that operate rotationally rather than vertically. Certain standards specify -,-,- SUBJECT 67 -6- N
41、OVEMBER 23,2005 handle position requirements for rotationally operated switch handles while others only detail requirements for switch handles which operate vertically. In determining which requirements are appropriate, it is noted that the applicable NEC requirement for the position of a switch han
42、dle is detailed in Section 404.7. This Code section requires switches which are operated vertically rather than rotationally or horizontally to be positioned such that the up position of the handle is the “ON” position. Examples of the varying handle position requirements are provided for reference:
43、 UL 98: 6.3.5 If a switch is operated such that movement of the operating handle is vertical between the on and off positions resulting in one position being above the other position, then the upper position shall be the on position. A switching device having more than one on position, such as a dou
44、ble-throw switch, need not comply with this requirement. UL 67: 13.1.3 If a circuit breaker or switch is mounted such that movement of the operating handle, either vertically or rotationally, between the on and off positions results in one position being above the other position, then the upper posi
45、tion shall be the on position. The requirement does not apply to a circuit breaker or switch that is operated rotationally and the on and offpositions are at the same level, nor to a switching device having two on positions such as a transfer switch or a double throw switch. UL 977: 12.1.10 If a swi
46、tch handle is operated vertically, the “on” handle position shall be the up position. Exception: Double-throw switches need not comply with this requirement. The STP agreed that requirements which state that the up position must be the “ON” position should not be applied to switch handles which oper
47、ate rotationally. UL agreed to develop and submit proposals to address this issue and harmonize the On-Off position requirements in all STP 67 standards. UL will present the proposal for preliminary STP review prior to balloting. 9. Screws Intended for Field Tightening and Located in the Back of Enc
48、losures (UL 98) MEETING DISCUSSION UL 98 was recently modified to include requirements for equipment grounding conductor screws located in the back of enclosures (reference paragraph 6.13.7). It has been suggested that this requirement be expanded to also cover screws used in conjunction with bondin
49、g jumpers. Additionally, it has been suggested that the existing requirement be clarified to indicate that the “back of the enclosure” is the “back plane of the enclosures intended mounting position”. The STP expressed general support for the development of the proposed requirement. UL will develop the proposal and present it to the Technical Harmonization Committee for UL 98 for their initial review. SUBJECT 67 -7- NOVEMBER 23,2005 I O . Updating of Ground-Fault Protection Requirements to Address use of Rating Plugs (UL 891 and 67) MEETING DI