Safety Codes Council Conference Banff C Panel Discussion

Transcription

1 Safety Codes Council Conference Banff C Panel Discussion Tim Driscoll OBIEC Consulting Ltd. George Morlidge Fluor Canada Ltd. Scott Basinger Eaton Canada René Leduc Marex Canada Limited

2 Perspectives Regulatory Compliance René Leduc Manufacturing Scott Basinger Engineering Design George Morlidge Owner / User Tim Driscoll Slide 2 / 90 C Panel Discussion/ Mar. 2014

3 Perspective: REGULATORY COMPLIANCE Slide 3 / 90 C Panel Discussion/ Mar. 2014

4 New 2012 Canadian Electrical Code Requirement Temperature limitations (see Appendix B) (1) Where equipment is marked with a maximum conductor termination temperature, the maximum allowable ampacity of the conductor shall be based on the corresponding temperature column from Table 1, 2, 3, or 4. (2) Where equipment is not marked with a maximum conductor termination temperature, 90 C shall be used by default. Slide 4 / 90 C Panel Discussion/ Mar. 2014

5 Why a Temperature Limitation? Part 2 standards require that testing be conducted using conductors with an insulation rating of 60 C and 75 C. Why no Temperature limitation Rule in 2009 and prior? Slide 5 / 90 C Panel Discussion/ Mar. 2014

6 Why a Temperature Limitation? Slide 6 / 90 C Panel Discussion/ Mar. 2014

7 Impact Terminating on equipment with temperature limitation None Choosing from the 75 C column now will achieve the same results (in terms of conductor sizing) as having selected from the 90 C column prior to 2012 Slide 7 / 90 C Panel Discussion/ Mar. 2014

8 Safety Codes Council Conference Banff 2014 Impact Termination on equipment with no temperature limitation Smaller sizes Less Copper Can use JB to transition to equipment with temp limitation Slide 8 / 90 C Panel Discussion/ Mar. 2014

9 Benefits of harmonizing conductor ampacities What benefits can be realized? 1. Cable spacing correction factors???: Example: 3-cond #14 TC cable each loaded to 12 A in 150 mm tray 2009 Code T5D not less than 25% spacing.82(cf) x 15A = 12.3A 2012 Code T5C no spacing (random fill).50(cf) x 25A = 12.5A Slide 9 / 90 C Panel Discussion/ Mar. 2014

10 Perspective ENGINEERING DESIGN Slide 10 / 90 C Panel Discussion/ Mar. 2014

11 Engineering design Watt Effect of additional ampacity to temperature Heat Loss for 1m Conductor - Tables Al-90 1-Cu-90 1-Al-75 1-Cu Al Cu Al-75 3-Cu Cross Section (mm2) Slide 11 / 90 C Panel Discussion/ Mar. 2014

12 Engineering design Its all about heat production and temperature Heat production is a squared function - i 2 r Most of our conductors end up operating at well below, lets conservatively say, 80 % of rated (Many are closer to 50 % in reality). That means they only produce less than 64 % of the heat (or 25 % of the heat at 50% rated). Our ambients are rarely anywhere near rated ambients We often put space heaters in these enclosures to drive off moisture. I really question whether utilizing 90 o C ampacity rated wire is really an issue because in reality, we will likely never see anywhere near the ideal conditions where this will be an issue. Slide 12 / 90 C Panel Discussion/ Mar. 2014

13 Engineering design Change the codes and standards to simplify and eliminate the need for (why would anyone buy 75 o C rated equipment if 90 o C equipment were available Most equipment that is presently manufactured will likely pass a 90 o C wire test The problem is that in many standards the only test is for 75 o C wire so therefore there is no test and the equipment is marked as 75 o C wire rated. The Technical Committee on Industrial Products (TCIP) has been approached to update all standards to add an additional optional test requirement for 90 o C wire Progressive manufacturers will test and mark to this standard. Slide 13 / 90 C Panel Discussion/ Mar. 2014

14 Engineering design Standards are changing In a recent standard voted on at CSA, the following clauses were included: C22.2 No Splitters 5.1 Information to be marked Slide 14 / 90 C Panel Discussion/ Mar. 2014

15 Engineering design M) where required by clause , the splitter shall be marked to indicate the conductor ampacity permitted with the following words or equivalent: 75 o C CONDUCTOR AMPACITY PERMITTED N) ) where required by clause , the splitter shall be marked to indicate the conductor ampacity permitted with the following words or equivalent: 90 o C CONDUCTOR AMPACITY PERMITTED Slide 15 / 90 C Panel Discussion/ Mar. 2014

16 Engineering design These are the clauses that will be added to all CSA standards in time giving the manufacturer the opportunity to test to the new 90 o C wire ampacities and mark his equipment accordingly In time, to be competitive, all equipment will be marked to meet the 90 o C conductor temperature requirement. The next step will be to move to 105 o C conductor temperature requirements. Slide 16 / 90 C Panel Discussion/ Mar. 2014

17 Perspective OWNER / USER Slide 17 / 90 C Panel Discussion/ Mar. 2014

18 Conductor Ampacities For many years, conductor ampacity was very limited in the CEC compared to the IEC world and also due to temperature constraints on insulation For several decades, 90 o C wire & cable has been available Today, you have to go out-of-the-way to buy 75 o C wire & cable 90 o C columns were introduced into the CEC Ampacity Tables many years ago However, they were essentially the same as the 75 o C columns So it didn t really matter what columns were used for sizing Slide 18 / 90 C Panel Discussion/ Mar. 2014

19 Conductor Ampacities (cont.) For the 2012 CEC, a major Ampacity harmonization effort with the NEC was performed Resulting in large increases for 90 o C over the 75 o C columns NEC had previously updated/uprated Ampacities Slide 19 / 90 C Panel Discussion/ Mar. 2014

20 Equipment Termination Ratings However, CEC Part ll Equipment standards have not kept up with Wire & Cable majority use 75 o C in the testing Some use 60 o C and very few use 90 o C Rule was also introduced in 2012 CEC along with Ampacity Table increases, to ensure Users size Wire & Cable per the rating of Equipment Terminations, generally 75 o C Net effect Wire & Cable ampacities essentially have not changed! One possible solution is to use a Jct. Box to splice in a larger conductor prior to Equipment termination Caution many Terminal Blocks / Wire Connectors are 75 o C rated This adds more equipment, time, space and cost to a termination Note much of this discussion applies to <1000V equipment, but not all Slide 20 / 90 C Panel Discussion/ Mar. 2014

21 Other 4-006(2): termination temperatures default to 90 o C if not marked Many manufacturers think this was in error and should be changed Rule (2) also introduced in 2012 CEC to Restrict #14, 12 and 10 conductors to be fed from 15, 20 and 30A max. Overcurrent protection respectively, regardless of ampacity Wire temperature ratings 90 o C is the standard available today However, 105 and 110 o C are starting to become readily available Slide 21 / 90 C Panel Discussion/ Mar. 2014

22 E.g. Supplemental CEC Sections Specific CEC sections may modify general sections Rules and Example Section 62 Electrical Heating Rule (1) for Branch conductors and (1) for Service and Feeder conductors Allow Ampacity Tables to be used directly Rule (7) Allows protection to be sized above the conductor ampacity rating On #14 conductor, can be up to 25A Load and 30A Overcurrent Slide 22 / 90 C Panel Discussion/ Mar. 2014

23 Conductor Rating Changes from 2009 CEC Cond Size 2009 CEC Amp, Cu Conductor 2012 CEC Adder over 2009 CEC 75/90 o C 75 o C 90 o C 75 o C 90 o C Current ratings ~5A above 2009 CEC ratings in smaller conductor sizes and 5-10A lower for larger conductor sizes Not a big change from 2009 on average If 90 o C column was available for sizing, current ratings average 10A higher for all conductor sizes A significant increase from 2009! Slide 23 / 90 C Panel Discussion/ Mar. 2014

24 Cost Examples for 90 o C vs 75 o C To take a look at a few examples 600V, 3 Cond. Cable Teck and Tray Small, medium and higher loads Ignoring Voltage Drop issues (many Users have Variances allowing more flexibility with Voltage Drop) Can be some Large Cost Savings, especially Tray cable Reduced by Users voltage drop criteria E.g. Load 3 Conductor 600V Cable Approx. Cost Savings (in using 90 o C Table) 75/90 o C Type 100m 300m 1000m 25A 12 / 14 Tray $ 184 $ 551 $ 1,837 Teck $ 53 $ 158 $ A 4 / 6 Tray $ 734 $ 2,201 $ 7,337 Teck $ 386 $ 1,158 $ 3, A 00 / 0 Tray $ 1,466 $ 4,399 $ 14,663 Teck $ 586 $ 1,759 $ 5,863 MV Cable constructions will also reduce net savings Significant cost savings are available, depending on design! Slide 24 / 90 C Panel Discussion/ Mar. 2014

25 Voltage Drop If voltage drop CEC criteria followed completely, little $ savings available However, since the voltage drop criteria is very restrictive, many Users have Variances to allow higher voltage drops Using examples from previous slide, 600V, 3 Phase #14 Cu good for 3%, and 8% #6 Cu good for 3%, and 8% 1/0 Cu good for 3%, and 8% Note lower voltages see higher % volt drop, as does 1 Phase Loads From these E.g. s, it can be seen that smaller conductors have more issues with volt drop constraints Slide 25 / 90 C Panel Discussion/ Mar. 2014

26 Summary A User s View Conductor Ampacities - very restrictive Some progress starting to be made Base ratings increased But many restrictions still in place net effect is little change so far Actions needed Change Part ll standards to allow 90 o C testing / marking Change Part ll standards to require 90 o C testing / marking Remove restrictions on Overcurrent Protection, CEC Rule (2) Then Users will start to see some $ savings Some premium may need to be paid for higher temperature 90 o C equipment, but wire & cable cost savings will more than offset Gives Users choice! Slide 26 / 90 C Panel Discussion/ Mar. 2014

27 Perspective MANUFACTURING Slide 27 / 90 C Panel Discussion/ Mar. 2014

28 CSA C , Section 4 Conductors Temperature limitations (see Appendix B) (1) Where equipment is marked with a maximum conductor termination temperature, the maximum allowable ampacity of the conductor shall be based on the corresponding temperature column from Table 1, 2, 3, or 4. (2) Where equipment is not marked with a maximum conductor termination temperature, 90 C shall be used by default. Slide 28 / 90 C Panel Discussion/ Mar. 2014

29 CSA C , Appendix B Notes on Rules Rule The intent of this Rule is to correlate the temperature rating of conductors where the ampacity is selected from Tables 1 to 4 with the lowest temperature rating of electrical equipment or any wire connector (terminal connector, lug, etc.). It is intended by this Rule that the ampacity of conductors be selected from the temperature column in Table 1, 2, 3, or 4 that corresponds to the temperature rating marked on the electrical equipment. Slide 29 / 90 C Panel Discussion/ Mar. 2014

30 CSA C , Appendix B Notes on Rules Rule (cont d) As an example, where a conductor is terminated on a breaker with a 75 C rating, the maximum conductor ampacity would be based on the 75 C column of the Tables. It should be noted that the temperature rating of a wire connector or lug that is connected to the equipment may be higher than that of the equipment itself; it is the equipment rating that determines the conductor size, not the lug. Slide 30 / 90 C Panel Discussion/ Mar. 2014

31 CSA C22.2 Product Safety Standards LET S LOOK AT SOME PART 2 STANDARDS Slide 31 / 90 C Panel Discussion/ Mar. 2014

32 CSA C22.2 No. 4: Enclosed and Dead- Front Switches A new switch shall be mounted as in actual service, with the door and other openings closed. The switch shall be wired with not less than 1.2 m (4 ft) of Type RH, TW, TW75, or THW copper wire per terminal, the wire size corresponding to the current rating of the switch. For a switch rated 30, 60, or 100 A, the wire size shall be based on the temperature rating of the wire as indicated by the marking on the switch (see ). Slide 32 / 90 C Panel Discussion/ Mar. 2014

33 CSA C22.2 No. 4: Enclosed and Dead- Front Switches (cont d) Where a dual temperature rating is marked 60/75 C wire, the test shall be conducted with 75 C wire. The test shall be made at any convenient voltage. A temperature shall be considered to be constant when three successive readings taken at 15-minute intervals do not indicate any change A switch shall be marked in a readily visible location to indicate the required temperature rating of all field-installed conductors. Slide 33 / 90 C Panel Discussion/ Mar. 2014

34 CSA C22.2 No. 5: Molded-Case Circuit Breakers, Molded Case Switches, and CB Enclosures Except as specified in , the conductors used in making the connections to a circuit breaker for the calibration tests of shall be of copper of the size indicated in Table (CEC Table 2 and 4 75 C column amperage) and no less than m (4 feet) in length, except that an accommodating fixture may be used for circuit breakers rated 100 A or less. For a circuit breaker or a circuit breaker frame with an interchangeable trip unit rated more than 30 A but not more than 125 A, the wire size shall be based on the temperature rating of the wire as indicated by the marking on the circuit breaker or trip unit. Where a dual wire temperature rating is marked, 60/75 C (140/167 F), the test shall be conducted with both size wires or the most adverse one, if it can be clearly determined. Slide 34 / 90 C Panel Discussion/ Mar. 2014

35 CSA C22.2 No. 5: Molded-Case Circuit Breakers, Molded-Case Switches, and CB Enclosures If a circuit breaker is marked for use with aluminum conductors only, all tests shall be conducted using aluminum conductors A circuit breaker that is intended to be operated continuously at 100 percent of its rating and that has a temperature rise on a wiring terminal exceeding 50 C (90 F), see and , shall be marked, Location Category B: a) For use with 90 C (194 F) wire and the wire size. The wire size shall be based on the ampacity of 75 C rated conductors as indicated in Table Slide 35 / 90 C Panel Discussion/ Mar. 2014

36 CSA C22.2 No. 14: Industrial control equipment 5.1 General marking requirements A permanent-type nameplate shall be attached to the individual component or complete assembly and provide (a) the manufacturer s name, trademark, or other descriptive marking; (b) the electrical rating; (c) the catalogue number or equivalent identifier; and (d) the temperature rating for the field-installed conductors for which the unit has been investigated, as follows: Slide 36 / 90 C Panel Discussion/ Mar. 2014

37 CSA C22.2 No. 14: Industrial control equipment (i) the rating shall be 60 C only, 60/75 C, or 75 C only; and (ii) a marking shall not be required for devices rated 30 A or less, or for horsepower-rated devices having an equivalent current rating of 24 A or less (see Tables 18A and 19), that have been tested when wired with 60 C or 60/75 C conductors. Note: For open-type equipment or in cases where it is not practical to place a mark on the device, this information may be placed on the smallest carton or on an instruction sheet included with the device. Slide 37 / 90 C Panel Discussion/ Mar. 2014

38 CSA C22.2 No. 29: Panelboards and enclosed panelboards Except as permitted in Clause 5.12, panelboards shall be provided with main and branch circuit wiring terminals suitable for the connection of conductor sizes selected from the 75/90 C column of Table 3 (CEC Table 2 and 4 75 C column amperage); for circuit breakers rated at 125 A or less and marked for use with 60 C wire only, the conductor sizes shall be selected from the 60 C column of Table 3. Example: 225A panel CSA spec 29 table specifies 4/0 corresponding to 75C table CEC 90C table 2 corresponding to this would be to test at 3/0 cable size. Slide 38 / 90 C Panel Discussion/ Mar. 2014

39 CSA C22.2 No. 31: Switchgear Assemblies This section is complicated somewhat by the fact that it covers both MV and LV assemblies. It allows for a temperature rise of 45C over a 40C ambient. The temperature requirement is similar in the ANSI C (Metal Enclosed LV Gear), 2 (Metal Clad MV) and 3 (Metal Enclosed MV) showing 90C cables as being specifically tested. MV gear is ok with 90C cables sized per 90C tables. NEC and manufacturer s labels can provide some guidance on the LV grey area, some labelling 75C. NEC (C)(1)(b)(2) is clear that this is to be 75C for LV. (which makes sense since it will connect to 75C equipment) Slide 39 / 90 C Panel Discussion/ Mar. 2014

40 CSA C22.2 No. 244: Switchboards A switchboard shall be provided with a marking readily visible prior to wiring to indicate the required temperature rating of fieldinstalled conductors If a circuit breaker is to be installed in the field, the marking shall indicate that the circuit breaker is to be marked either 60/75 C or 75 C if conductors sized for 75 C ampacity are to be used A switchboard or field wiring circuit rated more than 125 A shall be marked for use with conductors sized for 75 C ampacity With respect to , a switchboard that is marked to indicate that only 60 C field-installed conductors are to be used shall not reference a field-installed unit that has been investigated for 75 C conductors only. Slide 40 / 90 C Panel Discussion/ Mar. 2014

41 CSA C22.2 No. 244: Switchboards If the temperature rise exceeds 50 C on a wiring connector as covered in item 6 of Table 13, a marking shall be provided near the wiring connector indicating that 90 C wire shall be used and it shall be sized based on the ampacity of wire rated 75 C. If the switchboard is marked for use with aluminum or copper-clad aluminum conductors, there shall be a marking to indicate that the wire connectors shall be identified AL9, AL9CU, or CU9AL. The marking shall be: a) provided by the switchboard manufacturer if not already provided on the switch or circuit breaker and b) visible after installation. Slide 41 / 90 C Panel Discussion/ Mar. 2014

42 CSA C22.2 No. 254: Motor Control Centres Motor control centres shall be marked to indicate the temperature rating (60 C only, 60/75 C, or 75 C only) of the field-installed conductors for which the equipment has been investigated unless the field wiring terminal is only intended for the connection of a control circuit conductor. Slide 42 / 90 C Panel Discussion/ Mar. 2014

43 The Issue. Where equipment is not marked with a maximum conductor termination temperature, 90 C shall be used by default (4-006) For electrical equipment rated for 600V and less, terminations are typically rated 60 C, 75 C or 60 /75 C No distribution or utilization equipment is approved for the use of 90 C wire at its 90 C ampacity. Slide 43 / 90 C Panel Discussion/ Mar. 2014

44 The US Has Already Been Here Slide 44 / 90 C Panel Discussion/ Mar. 2014

45 Importance of temperature ratings One of the most common misapplications of conductor temperature ratings occurs when the established temperature rating of the equipment termination is ignored. This is particularly true for equipment rated for 600 V and lower, since it is tested as a complete system using conductors sized by NEC rules. Reduced conductor sizes result in the system having less ability to dissipate heat, and therefore increases the operating temperature of the equipment terminations. Conductors must be sized by considering where they will terminate and how that termination is rated. Slide 45 / 90 C Panel Discussion/ Mar. 2014

46 Importance of temperature ratings Frequently, manufacturers are asked when distribution equipment will be available with terminations that will permit 90 C conductors at 90 C ampacity. This would require not only significant equipment redesign (to handle the additional heat), but also coordination of downstream equipment where the other end of the conductor terminates. Significant changes in the product testing/listing standards also would have to occur. Slide 46 / 90 C Panel Discussion/ Mar. 2014

47 Cable Temp Ampacity Experiment Purpose: to determine the effect of using 90 o C ampacity sized cable on circuit breakers designed to use 75 o C ampacity sized cable Method: Install breaker into an enclosure and conduct a heat run test with: 1) 75 o C sized, min. 4ft of cable line and load, and 2) 90 o C sized min. 4ft of cable line and load Measure resulting temperature rise Slide 47 / 90 C Panel Discussion/ Mar. 2014

48 Cable Temp Ampacity Experiment Slide 48 / 90 C Panel Discussion/ Mar. 2014

49 Cable Temp Ampacity Experiment 600A 600A Slide 49 / 90 C Panel Discussion/ Mar. 2014

50 Results (Preliminary / Simple Testing Only) Breaker Size Cu size Diff Rise Diff % 11.0% % 21.1% % 12.3% 225L -20.6% 24.0% Temp Margin Diff -65.5% (Fail) -65.5% (Fail) -32.9% (Pass*) -57.3% (Pass*) * Preliminary Heat Rise Pass Only. Additional Tests would be req d. Slide 50 / 90 C Panel Discussion/ Mar. 2014

51 Panel Discussion Slide 51 / 90 C Panel Discussion/ Mar. 2014