1. 891 Switchboard vs. 1558 Switchgear
“The Rest of the Story II-
While you where sleeping”
2. 2
What happened since our last
discussion?????
• Selective coordination went on
steroids
• Arc Flash, Arc Resistant, and Arc
Fault overtook the NEC
• New UL ratings for everything and
nothing at the same time
• Mr. LEEDs is our new boss
3. 3
TVSS SPD – Another UL? – 3rd
addition
The major differences are:
Change in terminology from Transient Voltage Surge
Suppressors to Surge Protective Devices
UL 1449 3rd Edition is now an American National
Standard (ANSI)
Addition of Nominal Discharge Current to ratings and
markings
Duty cycle test at nominal discharge current
Measured limiting voltage now performed at 6 kV/3 kA
4. 4
TVSS 250 kA vs. 2 Billion kA
Based on available research, IEEE recommends
using the 20 kV, 10 kA combination wave as the
representative test for induced lightning surges
at service entrance locations. Above this amount,
the voltage will exceed BIL ratings causing
arcing in the conductors or distribution system.
In summary, low voltage wiring (<600V) is not
capable of conducting the lightning stroke
currents.
6. 6
Bolted Fault Arcing Fault
Systems must be designed However, the majority of faults
for worst case conditions. will be arcing type.
Line-to-Line-to-Line Fault
7. 7
What Can We Say About Arcing
Ground Fault Current Values?
9. 9
“Arc Mitigation” – What about the
Standards?
1. UL recognizes switchgear tested in accordance with IEEE C37.20.7 as Arc Resistant
Switchgear.
2. No ANSI or UL standards cover the testing or manufacturing of arc sensing relays or
mitigation components.
10. 10
ANSI C37.20.7
Type 1 - Arc resistant at front only
Type 2 - Arc resistant around the perimeter of the switchgear line-up
Appendix A
Type 1B or 2B - Arc resistant to type 1 or 2 with control door open.
Type 1C or 2C - Arc resistant to type 1or 2 plus between all adjacent
compartments (Meets all requirements of type and suffix B in addition to
the requirements of suffix C).
Type 1D - specifies Type 1 and applicable accessible sides
ARC Resistant Switchgear
11. 11
Arc Resistant type 2C
You must have arc resistance
from compartment 7 to the
following compartments
within this vertical section:
4,6,8
Additionally you must have
arc resistance from this
compartment 7 to the
compartment 7 in the vertical
section to the right and left of
vertical structure shown.
In order to validate this you
must initiate an arcing current
in compartment 7, and have
burn indicators placed in
each of these adjacent
compartments. You must
pass all arc resistant test
criterion
4
1
2
3
5
6
8
7
=Arcing fault in
compartment 7
16. 16
SD=
0.5S
SD=
0.3S
SD=
0.3S
SD=
0.3S
M1
F1 F2 F3X
35kA fault current
Without ZSI = 0.5 S:
43.7 Cal/cm2
Greater than Cat. 4 PPE
DANGER!
With ZSI = 0.08 S:
7.0 Cal/cm2
FR Shirt & Pants
Cat. 2 PPE
Safety (Wired for)
Solution #1 – ZSI
Short time
GF
17. 17
• ARMs features in white area of trip unit to separate
them from normal trip unit settings.
• Blue LED “Maintenance Mode”
• 2 Position Selector Switch:
• ON = Local ON
• O/I = OFF or External Control
• 5 Position Arc Flash Reduction Setting:
• From R5 (Max) …. To R1 (Min) Reduction
• Remote Indication:
• Power Relay Module Maintenance Mode Contact
• Communications
• Remote Enable:
• Switchgear Mounted Logic Level Selector Switch
• Switchgear Mounted Logic Level Ice Cube Relay
with Remote Mounted Control Switch
• Via Communications: Using Infa-Red Mint &
PDA, PowerNet, Modbus mMINT, & BIM
• Lock-out/Tag-out
5 levels of protection allow the operator to pre-
select the maximum arc flash reduction level
possible to avoid nuisance tripping during
maintenance operations
Safety
Solution #2 - ARMS
22. 22
Comparison of Standards
Endurance UL 1066 and UL 489 (continued)
* Maintenance of contacts is allowed under UL 1066
M-13
Required Nos. of Operations *
Electrical Mechanical
- - - -
- - - -
2,800 9,700
2,800 9,700
- - - -
800 3,200
- - - -
250 400
Pick-up and Time
Elements Tested:
• Long Time Delay
• Instantaneous
• Short Time Delay
1320 V
Must be able to carry Current
Provides for inspection,
cleaning, adjusting, lubricating
and tightening
O at 635V, 3-phase
FRAME SIZE
100 A
150 A and 225 A
600 A
800 A
801 A - 2500 A
1600 A or 2000 A
2501 A - 6000 A
3000 A, 4000 A or 5000 A
Short Circuit Current Test
Post-Test Trip Device Calibration
Post-Test AC Dielectric Withstand
V
Post-Test Condition of Circuit Bkr.
Maintenance
1240 - 2200 V
May not be able to CLOSE again
Internal servicing not permitted
O (2 - 60 min) - CO
One Pick-up and Time
200% Trip out at 25ºC
Required Nos. of Operations *
Electrical Mechanical
6,000 4,000
4,000 4,000
1,000 5,000
500 3,000
500 2,000
- - - -
400 1,100
400 1,100
UL 1066
Sequence III
UL 489
Sequence Y
Test Requirements
24. 24
Molded Case Circuit Breakers
• Tested in accordance with UL489
• Open Air Test - Rated @ 80%
• Over Toggle Mechanism
• Sealed Case - Not Maintainable
• Applied in Switchboards/Panelboards
Insulated Case Circuit Breakers
• Tested in accordance with UL489
• Open Air Test - Rated @ 80% or 100%
• 2-Step Stored Energy Mechanism
• Sealed Case - Not Fully Maintainable
• Applied As Mains in Switchboards/MCC’s
Power Circuit Breakers
• Tested in accordance with ANSI C37
• Tested in the Enclosure - Rated @ 100%
• 2-Step Stored Energy Mechanism
• Open Access - Fully Maintainable
• Applied in Metal-Enclosed Drawout Swgr.
UL489 versus ANSI C37
29. 29
What devices are required to
Selectively Coordinate?U TIL ITY A
M A I N A
M SG -A
M S G -TI E
U TI LITY B
M A IN B
M S G -B
A TS -EQ N O RM A T S-C R N O RM A T S- L S N O R MC H IL LE R F D R
G EN # 1 M A I N
G E N S W G R
A T S- EQ E M E R A TS -C R EM E R A TS -L S E M E R
G E N # 1
G E N # 2 M A I N
G E N # 2
EN
A T S- EQ
EN
A TS -C R
EN
A TS -L S
C B L-A T S EQ N C BL -A T S C R N C BL -A TS L S N C BL -0 00 5 C B L-0 0 06 C BL- 00 0 7
C B L -E Q 4 80 V P N L C BL -C R 4 8 0V PN L C BL -LS 4 80 V P N L
E Q 4 80 V P N L
EQ X F M R P R I
C B L -E Q X F M R P R I
S
P
E Q X F M R
C B L -E Q 2 08 V P N L
EQ 2 0 8V P N L M A IN
E Q 2 08 V P N L
EQ 2 0 8V B R A N CH
C R 4 8 0V PN L
C R X FM R P R I
C BL -C R X F M R P R I
S
P
C R X FM R
C BL -C R 2 0 8V PN L
C R 20 8 V P N L M AIN
C R 2 0 8V PN L
C R 20 8 V BR A N C H
L S 4 80 V P N L
L S X FM R P R I
C BL -LS X F M R PR I
S
P
L S X F M R
C BL -LS 2 08 V P N L
L S 2 0 8V PN L M A IN
L S 2 08 V P N L
L S 2 0 8V BR A N C H
C H ILL E R
C BL- C H ILLE R
D IS T R P N L FD R
C BL- D IST R P N L
D IS T R P N L
4 80 V LT G P N L F D R
C BL - 48 0V LT G P N L
48 0 V LT G P N L
LT G BR A N C H
4 80 V LR G S T
1. Load side of any
Emergency System ATS
2. Emergency
source to the
line side ATS
3. Normal
source to the
line side of the
ATS???
30. 30
U TIL ITY A
M A I N A
M SG -A
M S G -TI E
U TI LITY B
M A IN B
M S G -B
A TS -EQ N O RM A T S-C R N O RM A T S- L S N O R MC H IL LE R F D R
G EN # 1 M A I N
G E N S W G R
A T S- EQ E M E R A TS -C R EM E R A TS -L S E M E R
G E N # 1
G E N # 2 M A I N
G E N # 2
EN
A T S- EQ
EN
A TS -C R
EN
A TS -L S
C B L-A T S EQ N C BL -A T S C R N C BL -A TS L S N C BL -0 00 5 C B L-0 0 06 C BL- 00 0 7
C B L -E Q 4 80 V P N L C BL -C R 4 8 0V PN L C BL -LS 4 80 V P N L
E Q 4 80 V P N L
EQ X F M R P R I
C B L -E Q X F M R P R I
S
P
E Q X F M R
C B L -E Q 2 08 V P N L
EQ 2 0 8V P N L M A IN
E Q 2 08 V P N L
EQ 2 0 8V B R A N CH
C R 4 8 0V PN L
C R X FM R P R I
C BL -C R X F M R P R I
S
P
C R X FM R
C BL -C R 2 0 8V PN L
C R 20 8 V P N L M AIN
C R 2 0 8V PN L
C R 20 8 V BR A N C H
L S 4 80 V P N L
L S X FM R P R I
C BL -LS X F M R PR I
S
P
L S X F M R
C BL -LS 2 08 V P N L
L S 2 0 8V PN L M A IN
L S 2 08 V P N L
L S 2 0 8V BR A N C H
C H ILL E R
C BL- C H ILLE R
D IS T R P N L FD R
C BL- D IST R P N L
D IS T R P N L
4 80 V LT G P N L F D R
C BL - 48 0V LT G P N L
48 0 V LT G P N L
LT G BR A N C H
4 80 V LR G S T
What devices are required to
Selectively Coordinate?
3. Normal
source to the
line side of the
ATS???
Is this Zone important
for continuity of service?
This bus sees an unnecessary
outage. ATS transfers into a fault.
Gen feeds a fault. Normal ATS
breaker must be reset for ATS to
transfer back
32. 32
Why .1 seconds?
“Operating records show that the majority of electric faults originate
as phase-to-ground failures.” IEEE std. 141-1993, page 187. (Red
book)
“It should be recognized, however, that actual short circuits often
involve arcing, and variable arc impedance can reduce low-voltage
short-circuit current magnitudes appreciably.” IEEE std. 141-1993,
page 113. (Red book)
Looking at TCC’s, fault currents that cause operation of OCPD’s in
the sub 6 cycle range have been found to be rare occurrences for
systems that have already been safely energized.
35. 35
Ground Faults on low-voltage
systems
“Arcing faults are the more destructive type of
fault because the arc limits the fault current.”
“Selectivity can be typically achieved only by
including more than one level of ground fault
relays.”
IEEE std. 142-2001, page 626. (Buff book)
36. 36
How GFP Effects Coordination
From NEC 517-17: (a) Feeders“ Where GFP is
provided for operation of the service
disconnecting means ----an additional step of
GFP shall be provided in the next level of feeder
disconnecting means downstream toward the
load.”
This is a healthcare requirement.
37. 37
More from NEC 517-17
(b) Selectivity. “ GFP for operation of the service feeder
disconnecting means shall be fully selective such that the
feeder device and not the service device shall open on
ground faults on the load side of the feeder device. A six
cycle minimum separation between the service and
feeder GF tripping bands shall be provided.”
Why 6 cycles? (OCPD opening time).
Note: only GFP is referenced here.
39. Specific Application Circuit Breakers
Motor Starting
Motor Circuit Protectors
Motor Starting Considerations
National Electrical Code 430-52
Maximum instantaneous setting 13x FLA
First peak may be 17-18x FLA or higher
on energy efficient motors
HMCP size 0-4 transient inrush trip suppressor
- Sustain high inrush for first cycle
- Provide sensitive, adjustable short-circuit protection
40. Specific Application Circuit Breakers
HMCP
Motor Circuit
Protectors
Adjustable Trip Settings
Multiples of continuous
current rating
Field adjustable
Close coordination
with motor
characteristics
44. 44
Bolted Fault Arcing Fault
Systems must be designed However, the majority of faults
for worst case conditions. will be arcing type.
Line-to-Line-to-Line Fault
45. 45
Why .1 seconds?
“Operating records show that the majority of electric faults originate
as phase-to-ground failures.” IEEE std. 141-1993, page 187. (Red
book)
“It should be recognized, however, that actual short circuits often
involve arcing, and variable arc impedance can reduce low-voltage
short-circuit current magnitudes appreciably.” IEEE std. 141-1993,
page 113. (Red book)
Looking at TCC’s, fault currents that cause operation of OCPD’s in
the sub 6 cycle range have been found to be rare occurrences for
systems that have already been safely energized.
46. 46
Does .1 Seconds make Sense -
Types and Frequencies of Faults
“Operating records show that the majority of electric
faults originate as phase-to-ground failures.” IEEE std.
141-1993, page 187. (Red book)
“It should be recognized, however, that actual short
circuits often involve arcing, and variable arc impedance
can reduce low-voltage short-circuit current magnitudes
appreciably.” IEEE std. 141-1993, page 113. (Red book)
