Safety Codes Council Conference
Banff 2014
90°C Panel Discussion
Tim Driscoll – OBIEC Consulting Ltd.
George Morlidge – Fluor Canada Ltd.
Scott Basinger – Eaton Canada
René Leduc – Marex Canada Limited
Safety Codes Council Conference
Perspectives
• Regulatory Compliance
• René Leduc
• Manufacturing
• Scott Basinger
• Engineering Design
• George Morlidge
• Owner / User
• Tim Driscoll
Slide 2 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
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Perspective:
REGULATORY COMPLIANCE
Slide 3 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 4 / 90°C Panel Discussion/ Mar. 2014
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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
Banff 2014
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Why a Temperature Limitation?
Slide 6 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
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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
Banff 2014
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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
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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
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Perspective
ENGINEERING DESIGN
Slide 10 / 90°C Panel Discussion/ Mar. 2014
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Engineering design
Effect of additional ampacity to temperature
1-Al-90
60
1-Cu-90
Heat Loss for 1m Conductor - Tables 1-4
50
Watt
1-Al-75
40
1-Cu-75
30
3-Al-90
3-Cu-90
20
3-Al-75
10
3-Cu-75
0
0
100
200
Slide 11 / 90°C Panel Discussion/ Mar. 2014
300
400
500
600
Cross Section (mm2)
700
800
900
1000
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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.
Slide 12 / 90°C Panel Discussion/ Mar. 2014
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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 oC
equipment 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 oC
wire 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.
Slide 13 / 90°C Panel Discussion/ Mar. 2014
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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 …
Slide 14 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 15 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 16 / 90°C Panel Discussion/ Mar. 2014
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Perspective
OWNER / USER
Slide 17 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 18 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 19 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 20 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 21 / 90°C Panel Discussion/ Mar. 2014
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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
Slide 22 / 90°C Panel Discussion/ Mar. 2014
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Banff 2014
Conductor Rating Changes from 2009 CEC
Cond
Size
14
12
10
8
6
4
3
2
1
0
00
2009
CEC
2012 CEC
Adder over
Amp, Cu
Conductor
2009 CEC
75/90oC
75oC
90oC
75oC
90oC
15
20
30
45
65
85
105
120
140
155
185
20
25
35
50
65
85
100
115
130
150
175
25
30
40
55
75
95
115
130
145
170
195
5
5
5
5
0
0
-5
-5
-10
-5
-10
10
10
10
10
10
10
10
10
5
15
10
Slide 23 / 90°C Panel Discussion/ Mar. 2014
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 !
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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)
E.g.
Load
25A
70A
Can be some Large Cost
Savings, especially Tray cable
Reduced by Users’ voltage
drop criteria
75/90oC
Type
12 / 14
Tray
$
184 $
551 $
1,837
Teck
$
53 $
158 $
528
Tray
$
734 $
2,201 $
7,337
Teck
$
386 $
1,158 $
3,861
Tray
$ 1,466 $
4,399 $ 14,663
Teck
$
1,759 $
4/6
160A
Approx. Cost Savings
(in using 90oC Table)
3 Conductor
600V Cable
00 / 0
100m
586 $
300m
1000m
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
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Banff 2014
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
Slide 25 / 90°C Panel Discussion/ Mar. 2014
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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 !
Slide 26 / 90°C Panel Discussion/ Mar. 2014
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Perspective
MANUFACTURING
Slide 27 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
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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.
Slide 28 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 29 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 30 / 90°C Panel Discussion/ Mar. 2014
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CSA C22.2 Product Safety Standards
LET’S LOOK AT SOME PART 2
STANDARDS…
Slide 31 / 90°C Panel Discussion/ Mar. 2014
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CSA C22.2 No. 4: Enclosed and DeadFront 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).
Slide 32 / 90°C Panel Discussion/ Mar. 2014
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CSA C22.2 No. 4: Enclosed and DeadFront 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.
Slide 33 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 34 / 90°C Panel Discussion/ Mar. 2014
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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.
Slide 35 / 90°C Panel Discussion/ Mar. 2014
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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:
Slide 36 / 90°C Panel Discussion/ Mar. 2014
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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
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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.
Slide 38 / 90°C Panel Discussion/ Mar. 2014
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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)
Slide 39 / 90°C Panel Discussion/ Mar. 2014
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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 fieldinstalled 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.
Slide 40 / 90°C Panel Discussion/ Mar. 2014
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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 and
b) visible after installation.
Slide 41 / 90°C Panel Discussion/ Mar. 2014
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Banff 2014
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.
Slide 42 / 90°C Panel Discussion/ Mar. 2014
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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
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The US Has Already Been Here
Slide 44 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
Safety Codes Council Conference
Banff 2014
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
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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
Safety Codes Council Conference
Banff 2014
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
Slide 47 / 90°C Panel Discussion/ Mar. 2014
Safety Codes Council Conference
Cable Temp Ampacity Experiment
Slide 48 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
Safety Codes Council Conference
Cable Temp Ampacity Experiment
600A
600A
Slide 49 / 90°C Panel Discussion/ Mar. 2014
Banff 2014
Safety Codes Council Conference
Banff 2014
Results (Preliminary / Simple Testing
Only)
Breaker Size Cu size Diff
Rise Diff
800
-16.4%
11.0%
600
-14.1%
21.1%
225
-20.6%
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
Safety Codes Council Conference
Panel Discussion
Slide 51 / 90°C Panel Discussion/ Mar. 2014
Banff 2014