90°C Panel Discussion - Safety Codes Council 4 / 90 C Panel Discussion/ Mar. 2014 Safety Codes...

Safety Codes Council ConferenceBanff 2014

90°C Panel Discussion

Tim Driscoll – OBIEC Consulting Ltd.

George Morlidge – Fluor Canada Ltd. Scott Basinger – Eaton Canada

René Leduc – Marex Canada Limited

/ 90°C Panel Discussion/ Mar. 2014

Safety Codes Council Conference Banff 2014

Perspectives

• Regulatory Compliance

• René Leduc

• Manufacturing

• Scott Basinger

• Engineering Design

• George Morlidge

• Owner / User

• Tim Driscoll



REGULATORY COMPLIANCE

Perspective:



New 2012 Canadian Electrical Code Requirement

4-006 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.



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?



Why a Temperature Limitation?



Impact – Terminating on equipment withtemperature 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



Impact – Termination on equipment with no temperature limitation

• Smaller sizes

• Less Copper

• Can use JB to transition to equipment with temp limitation



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



ENGINEERING DESIGN

Perspective



Engineering design

Effect of additional ampacity to temperature

0

10

20

30

40

50

60

0 100 200 300 400 500 600 700 800 900 1000

Wa

tt

Cross Section (mm2)

Heat Loss for 1m Conductor - Tables 1-4

1-Al-90

1-Cu-90

1-Al-75

1-Cu-75

3-Al-90

3-Cu-90

3-Al-75

3-Cu-75



Engineering design

Its all about heat production and temperature

Heat production is a squared function - i2r

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.



Engineering design

Change the codes and standards to simplify and eliminate the need for 4-006 (why would anyone buy 75 oC rated equipment if 90 oCequipment were available

Most equipment that is presently manufactured will likely pass a 90 oC wire test

The problem is that in many standards the only test is for 75 oCwire so therefore there is no test and the equipment is marked as 75 oC 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 oC wire

Progressive manufacturers will test and mark to this standard.



Engineering design

Standards are changing

– In a recent standard voted on at CSA, the following clauses were included:

• C22.2 No. 76-13 Splitters

– 5.1 Information to be marked …



Engineering design

M) where required by clause 4.2.3.4, the splitter shall be marked to indicate the conductor ampacity permitted with the following words or equivalent: 75 oC CONDUCTOR AMPACITY PERMITTED

N) ) where required by clause 4.2.3.4, the splitter shall be marked to indicate the conductor ampacity permitted with the following words or equivalent: 90 oC CONDUCTOR AMPACITY PERMITTED



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 oC wire ampacities and mark his equipment accordingly

In time, to be competitive, all equipment will be marked to meet the 90 oC conductor temperature requirement.

The next step will be to move to 105 oC conductor temperature requirements.



OWNER / USER

Perspective



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, 90oC wire & cable has been available� Today, you have to go out-of-the-way to buy 75oC wire & cable

� 90oC columns were introduced into the CEC Ampacity Tables many years ago� However, they were essentially the same as the 75oC columns

� So it didn’t really matter what columns were used for sizing



Conductor Ampacities (cont.)

� For the 2012 CEC, a major Ampacity harmonization effort with the NEC was performed� Resulting in large increases for 90oC over the 75oC columns

� NEC had previously updated/uprated Ampacities



Equipment Termination Ratings

� However, CEC Part ll Equipment standards have not kept up with Wire & Cable – majority use 75oC in the testing� Some use 60oC and very few use 90oC

� Rule 4-006 was also introduced in 2012 CEC along with Ampacity Table increases, to ensure Users size Wire & Cable per the rating of Equipment Terminations, generally 75oC

� 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 75oC rated

� This adds more equipment, time, space and cost to a termination

� Note – much of this discussion applies to <1000V equipment, but not all



Other

� 4-006(2): termination temperatures default to 90oC if not marked� Many manufacturers think this was in error and should be changed

� Rule 14-104(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� 90oC is the standard available today

� However, 105 and 110oC are starting to become readily available



E.g. Supplemental CEC Sections

� Specific CEC sections may modify general sections Rules 4-006 and 14-104

� Example – Section 62 Electrical Heating� Rule 62-108(1) for Branch conductors and 62-116(1) for Service

and Feeder conductors

• Allow Ampacity Tables to be used directly

� Rule 62-114(7)

• Allows protection to be sized above the conductor ampacity rating

• On #14 conductor, can be up to 25A Load and 30A Overcurrent



Conductor Rating Changes from 2009 CEC

� 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 90oC column was available for sizing, current ratings average 10A higher for all conductor sizes

� A significant increase

from 2009 !

Cond

Size

2009

CEC

2012 CEC

Amp, Cu

Conductor

Adder over

2009 CEC

75/90oC 75oC 90oC 75oC 90oC

14 15 20 25 5 10

12 20 25 30 5 10

10 30 35 40 5 10

8 45 50 55 5 10

6 65 65 75 0 10

4 85 85 95 0 10

3 105 100 115 -5 10

2 120 115 130 -5 10

1 140 130 145 -10 5

0 155 150 170 -5 15

00 185 175 195 -10 10



Cost Examples for 90oC vs 75oC

� 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

� MV Cable constructions will also reduce

net savings

Significant cost savings are available, depending on design !

E.g.

Load

3 Conductor

600V Cable

Approx. Cost Savings

(in using 90oC Table)

75/90oC Type 100m 300m 1000m

25A 12 / 14 Tray $ 184 $ 551 $ 1,837

Teck $ 53 $ 158 $ 528

70A 4 / 6 Tray $ 734 $ 2,201 $ 7,337

Teck $ 386 $ 1,158 $ 3,861

160A 00 / 0 Tray $ 1,466 $ 4,399 $ 14,663

Teck $ 586 $ 1,759 $ 5,863



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 90m @ 3%, and 230m @ 8%

• #6 Cu good for 200m @ 3%, and 530m @ 8%

• 1/0 Cu good for 350m @ 3%, and 930m @ 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



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 90oC testing / marking

� Change Part ll standards to require 90oC testing / marking

� Remove restrictions on Overcurrent Protection, CEC Rule 14-104(2)

� Then Users will start to see some $ savings

� Some premium may need to be paid for higher temperature 90oC equipment, but wire & cable cost savings will more than offset

� Gives Users choice !



MANUFACTURING

Perspective



CSA C22.1-12, Section 4 — Conductors

4-006 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.



CSA C22.1-12, Appendix B — Notes on Rules

Rule 4-006

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.



CSA C22.1-12, Appendix B — Notes on Rules

Rule 4-006 (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.



LET’S LOOK AT SOME PART 2 STANDARDS…

CSA C22.2 Product Safety Standards



CSA C22.2 No. 4: Enclosed and Dead-Front Switches

7.2.4 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 9.2.47).



CSA C22.2 No. 4: Enclosed and Dead-Front Switches

7.2.4 (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.

9.2.47 A switch shall be marked in a readily visible location to indicate the required temperature rating of all field-installed conductors.



CSA C22.2 No. 5: Molded-Case Circuit Breakers, Molded Case Switches, and CB Enclosures

7.1.2.1.5 Except as specified in 7.1.1.14, the conductors used in making the connections to a circuit breaker for the calibration tests of 7.1.2.2 shall be of copper of the size indicated in Table 6.1.4.2.1 (CEC Table 2 and 4 75°C column amperage) and no less than 1.219 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.



CSA C22.2 No. 5: Molded-Case Circuit Breakers, Molded-Case Switches, and CB Enclosures

7.1.1.14 If a circuit breaker is marked for use with aluminum conductors only, all tests shall be conducted using aluminum conductors. 9.1.2.14 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 7.1.4.3.1 and 7.1.4.3.2, 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 6.1.4.2.1.



CSA C22.2 No. 14: Industrial control equipment

5.1 General marking requirements 5.1.1 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:



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.



CSA C22.2 No. 29: Panelboards and enclosed panelboards

5.11.1 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. 2012 CEC 90C table 2 corresponding to this would be to test at 3/0 cable size.



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 C37.20.1 (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 110.14(C)(1)(b)(2) is clear that this is to be 75C for LV. (which makes sense since it will connect to 75C equipment)



CSA C22.2 No. 244: Switchboards

6.2.6.18 A switchboard shall be provided with a marking readily visible prior to wiring to indicate the required temperature rating of field-installed conductors.

6.2.6.19 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. 6.2.6.20 A switchboard or field wiring circuit rated more than 125 A shall be marked for use with conductors sized for 75°C ampacity. 6.2.6.21 With respect to 6.2.6.18, 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.



CSA C22.2 No. 244: Switchboards

6.2.6.23 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 andb) visible after installation.



CSA C22.2 No. 254: Motor Control Centres

6.3.27 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.



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.



The US Has Already Been Here



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.



“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 theproduct testing/listing standards also would have to occur.

Importance of temperature ratings



Cable Temp Ampacity Experiment

Purpose:

– to determine the effect of using 90oC ampacity sized cable on circuit breakers designed to use 75oC ampacity sized cable

Method:

– Install breaker into an enclosure and conduct a heat run test with:

• 1) 75oC sized, min. 4ft of cable line and load, and

• 2) 90oC sized min. 4ft of cable line and load

Measure resulting temperature rise




600A

600A



Results (Preliminary / Simple Testing Only)

Breaker Size Cu size Diff Rise DiffTemp Margin

Diff

800 -16.4% 11.0%-65.5% (Fail)

600 -14.1% 21.1%-65.5%(Fail)

225 -20.6% 12.3%-32.9%(Pass*)

225L -20.6% 24.0%-57.3%(Pass*)

* Preliminary Heat Rise Pass Only. Additional Tests would be req’d.



Panel Discussion

90°C Panel Discussion - Safety Codes Council 4 / 90 C Panel Discussion/ Mar. 2014 Safety Codes...

Documents

Transcript of 90°C Panel Discussion - Safety Codes Council 4 / 90 C Panel Discussion/ Mar. 2014 Safety Codes...