4100DB0301R9/04
09/2004
Lexington, KY, USA
Data Bulletin
Square D® Load Center Short-Circuit Current Ratings
Retain for future use.
INTRODUCTION
This document defines fully-rated systems, two-tier series short circuit
current protection and three-tier series short circuit current protection. It also
addresses NEC® requirements and illustrates series rating labels currently
provided with Square D® multi-metering and load center equipment. The
location of series rating labels applied to Square D load centers is depicted
on pages 2 and 4 of this document.
Fully-Rated System
In a fully rated system, the interrupting rating of all the overcurrent protective
devices must be greater than or equal to the available fault current at the
line side terminals of each device.
Series-Rated System
The NEC and UL® permit assigning a short circuit current rating to a tested
combination of circuit breakers or fuses that is higher than the individual
rating of the downstream overcurrent protective device. Testing by the
circuit breaker manufacturer demonstrates that the combination can safely
interrupt the available fault current.
NEMA defines a series rating as follows:
Series Rating - A short-circuit interrupting rating assigned to a
combination of two or more overcurrent protective devices which are
connected in a series and in which the rating of the downstream
device(s) in the combination is less than the series rating.
The combination of overcurrent protective devices may be enclosed in a
single piece of equipment such as a load center. Three-tier series rated
systems are most commonly designed with the supply side device in a
separate enclosure, such as metering equipment, that feeds a load center.
NOTE: The load-side device is always a circuit breaker. The supply-side
device may be either a circuit breaker or a set of current-limiting fuses.
Two-Tier Series Rating
A two-tier series rating can be used within a single enclosure (Example 1) or
in separate enclosures (Example 2).
Example 1: QO® Main Circuit Breaker Load Center
22 kA
QOM VH 200 A
QO 30 A
Example 2: MP Meter-Pak™ feeding Homeline Main Lug Load Center
22 kA
10 kA
QOM MVH 200 A
HOM 30 A
1
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
4100DB0301R9/04
09/2004
Location of Two-Tier Series Ratings
Label in Square D Equipment
The permitted NEC and UL series ratings are found marked in the
equipment. Unless the equipment is marked, one cannot be assured the
breaker combination will perform appropriately in the enclosure. Square D
marks two-tier series ratings on the inside wall of load centers (See
Figure 1). The two-tier series rating labels applied to current production
convertible main QO® and Homeline® load centers are depicted in Figures
2 and 3, respectively.
NOTE: The information contained in this data bulletin is current at time of
printing; however, ratings may change or additional ratings may be added
without notice. Refer to the series-connected ratings marked in the
equipment.
Figure 1:
Two-Tier Series Ratings Label Application
Two-tier series rating labels are applied to the side wall
of current production QO and Homeline load centers.
Figure 2:
QO Two-Tier Series Ratings Labels for Convertible Main Load Centers
SHORT CIRCUIT CURRENT RATING
SHORT CIRCUIT CURRENT RATING
Integral or Remote Fuse
RMS Symmetrical
Class or Circuit Breaker
Amperes at ___Vac Max.
Catalog Designation
(Max. A)
Branch Circuit Breaker
Catalog Designation
(Max. A)
5,000 at 240
QO-H
10,000 at 240
QO (125)
10,000 at 240
25,000 at 240
65,000 at 240
QO-VH (100)
QO (100)
QD (125)
QO (125)
QO (100) ¥ QOT
QO-VH (100) §
22,000
25,000
QOM-VH (125)
QO-VH (125)
QO (100) ¥ QOT
QD (125)
QO (100) ¥ QOT
QOH
QO (100) ¥ QOT
QG (125)
QO (100) ¥ QOT
T3 (125)
QJ (125)
QO (100) ¥ QOT
QH
QG (125)
QO (125)
100,000 at 240
T3 (125)
QO (125)
100,000 at 208Y/120
QJ (125)
1-Pole QO
2-Pole QO (125)
3-Pole QO (30) ,
3-Pole QO-VH (100)
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
3 Ø 3 W Grounded B Phase
QO includes QO-GFI, QO-EPD, QO-PL, QO-AS, and QO-AFI.
§ QO-VH includes QO-VHGFI and QO-VHAFI.
Three-Phase QO Load Centers 125 A Max.
2
QO-H
5,000
10,000
QO-H
QO-VH (125) §
22,000 at 240
Integral or Remote Fuse Branch Circuit Breaker
RMS Symmetrical
Class or Circuit Breaker
Catalog Designation
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
(Max. A)
42,000
QOH (100)
QH
65,000
100,000
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
3 Ø 3 W Grounded B Phase
¥ QO includes QO-GFI, QO-EPD, QO-PL, QO-AS, and QO-AFI.
§ QO-VH includes QO-VHGFI and QO-VHAFI.
Single-Phase QO Load Centers 125 A Max.
© 2003–2004 Schneider Electric All Rights Reserved
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
4100DB0301R9/04
09/2004
Figure 2:
(Continued) QO Two-Tier Series Ratings Labels for Convertible Main Load Centers
SHORT CIRCUIT CURRENT RATING
SHORT CIRCUIT CURRENT RATING
Integral or Remote Fuse Branch Circuit Breaker
RMS Symmetrical
Class or Circuit Breaker
Catalog Designation
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
(Max. A)
QO-H
5,000
10,000
QO (125) ¥ QOT
22,000
QO-VH (125) §
QOM-VH (200)
25,000
42,000
QOM-VH (200)
QO-VH
QO (125) ¥ QOT
QD (200)
QO (125) ¥ QOT
QOH
QOH
QO (125) ¥ QOT
QG (200)
QO (125) ¥ QOT
T3 (200)
QJ (200)
QO (125) ¥ QOT
QH
65,000
100,000
Single-Phase QO Feed-Through Load Centers 200 A Max.
QO-H
5,000
10,000
QO ¥ QOT
QO-VH §
22,000
25,000
QOM-VH
QO-VH
QO ¥ QOT
QD (225)
QO ¥ QOT
QOH
QO (125) ¥ QOT
QG (225)
QO ¥ QOT
T3 (200)
QJ (225)
QO ¥ QOT
QOH
42,000
QH
65,000
100,000
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
3 Ø 3 W Grounded B Phase
¥ QO includes QO-GFI, QO-EPD, QO-PL, QO-AS, and QO-AFI.
§ QO-VH includes QO-VHGFI and QO-VHAFI.
Figure 3:
Integral or Remote Fuse Branch Circuit Breaker
RMS Symmetrical
Class or Circuit Breaker
Catalog Designation
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
(Max. A)
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
3 Ø 3 W Grounded B Phase
¥ QO includes QO-GFI, QO-EPD, QO-PL, QO-AS, and QO-AFI.
§ QO-VH includes QO-VHGFI and QO-VHAFI.
Single-Phase QO Load Centers 150 A—225 A
Homeline Two-Tier Series Ratings Labels for Convertible Main Load Centers
SHORT CIRCUIT CURRENT RATING
Integral or Remote Fuse
RMS Symmetrical
Class or Circuit Breaker
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
Branch Circuit Breaker
Catalog Designation
(Max. A)
10,000
SHORT CIRCUIT CURRENT RATING
Integral or Remote Fuse
RMS Symmetrical
Class or Circuit Breaker
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
Branch Circuit Breaker
Catalog Designation
(Max. A)
10,000
22,000
QOM-VH (125)
QO-VH (125)
25,000
QD (125)
42,000
QOH
65,000
100,000
22,000
QOM-VH
QO-VH
25,000
QD (225)
42,000
QOH
QG (125)
65,000
QG (225)
QJ (125)
100,000
QJ (225)
HOM (100) ¥ HOMT
HOM ¥, HOMT
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
¥ HOM includes HOM-GFI, HOM-EPD, and HOM-AFI.
¥ HOM includes HOM-GFI, HOM-EPD, and HOM-AFI.
Homeline Load Centers 125 A Max.
Homeline Load Centers 150 A—225 A Max.
SHORT CIRCUIT CURRENT RATING
Integral or Remote Fuse
RMS Symmetrical
Class or Circuit Breaker
Amperes at 240 Vac Max. Catalog Designation
(Max. A)
Branch Circuit Breaker
Catalog Designation
(Max. A)
10,000
22,000
QOM-VH (200)
QO-VH
25,000
QD (200)
42,000
QOH
65,000
QG (200)
100,000
QJ (200)
HOM ¥, HOMT
The rating is equal to the lowest interrupting rating of any circuit breaker installed or
combination series connected circuit breaker. Additional or replacement circuit breakers
MUST have an interrupting rating equal to or greater than that of the circuit breaker with
the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types.
¥ HOM includes HOM-GFI, HOM-EPD, and HOM-AFI.
Homeline Universal Main Load Centers
© 2003–2004 Schneider Electric All Rights Reserved
3
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
Three-Tier Series Rating
4100DB0301R9/04
09/2004
A three-tier series rating consists of three levels of overcurrent protection
devices (the furthest load-side device being a circuit breaker). Per NEC
240.86, this three-tier combination of overcurrent protection must be marked
on the end-use electrical equipment (load center). See Example 3.
Example 3: EZM® Fusible Main Device feeding EZM Branch Device
feeding Homeline Main Lug Load Center (100 kA Three-Tier Series Rating)
10 kA
100 kA
Class T
(300 Vac)
QO VH 125 A
Location of Three-Tier Series Ratings in
Square D Equipment
HOM 30 A
For convertible main load centers, three-tier series ratings labels are applied
on the back side of indoor load center covers and on outdoor load center
deadfronts (See Figure 4). The information contained on this three-tier
series rating label is shown in Figure 5.
For single-phase fixed main indoor and outdoor load centers, two-tier and
three-tier ratings are printed on the same label. This label is located on the
left side wall (See Figure 4). The information contained on the series rating
label for single-phase fixed main load centers is depicted in Figure 5.
Figure 4:
Convertible Main Load Centers Label Locations
Three-tier series rating label is applied to the dead front trim of current
production convertible main QO and Homeline outdoor load centers.
Figure 4a:
Three-tier series rating label is applied to the backside of current production
convertible main QO and Homeline covers for indoor load centers.
Fixed Main Load Center Label Locations
Two-tier / three-tier series rating label is applied to left side wall of
current production single-phase fixed main QO and Homeline indoor
and outdoor load centers.
4
© 2003–2004 Schneider Electric All Rights Reserved
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
4100DB0301R9/04
09/2004
Figure 5:
Three-Tier Series Ratings Label Applied to Convertible Main QO and Homeline Load Centers
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
SQUARE D Tenant Circuit Breaker
(Integral or Remote)
Poles
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
100
50
HOM§
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
2,3
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
Figure 6:
HOMT
HOM §
HOMT
30
50
50
30
200
50
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
Two-Tier / Three-Tier Series Rating Label Applied to Fixed Main Homeline Load Centers
SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS Line Side Square D Circuit Breaker
Symmetrical Amperes at Catalog Designation or Fuse Class
120 / 240 Vac Maximum
Maximum Ampere Rating
Poles
Square D Tenant Circuit Breaker
(Remote Only)
Catalog
Designation
Poles
Square D Circuit Breakers
Max. Ampere Rating
1-Pole
2-Pole
Catalog
Max. Ampere
Designation
Rating
10,000
22,000
25,000
42,000
42,000
65,000
100,000
42,000
2
QO-VH (125)
QD (225)
2
2
QOH
2,3
LA, MA
Class T3
2,3
LH, MH, PA (1600)
QO-VH
2
125
MHF,
Class R, J, T3 (800)
2,3
QD
2,3
2
LA, MA
225
QG (225)
2
65,000
2
LH, MG, MH, PG, PA (1600), RG (2000)
QD
2,3
225
QJ (225)
2
100,000
MJ, MHF, PJ, PH (1600), RJ (2000),
225
QD
2,3
2
Class R, J, T6, T3, L (1200)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series
connected circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than
that of the circuit breaker with the lowest interrupting rating presently installed. See panelboard wiring diagram for
circuit breaker types. See circuit breaker for voltage and interrupting rating.
HOM §
HOMT
50
30
125 ¶
50
HOM §
HOMT
50
30
100 ¶
50
HOM §
HOMT
50
30
125 ¶
50
§ Catalog Designation HOM
includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
¶ Load centers with 100 A mains rating are limited to 100 A maximum
integral main circuit breaker and 70 A maximum branch circuit breaker.
Figure 7:
Two-tier/Three-Tier Series Ratings Label applied to Single Phase Fixed Main QO Load Centers
SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes at
120 / 240 Vac Maximum
Fuse Class
(Max. Ampere Rating)
5,000
10,000
22,000
25,000
42,000
42,000
42,000
65,000
100,000
Square D Tenant Circuit Breaker Square D Circuit Breakers
(Remote Only)
Line Side Fuse or Square D Circuit Breaker
Catalog Designation
(Max. Ampere Rating)
Poles
Catalog
Designation
Max. A Rating
Catalog
Poles Max. A
Rating Designation 1-Pole 2-Pole
QO-H
100 ¶
QO
QO-VH (125)
QD (225)
QOH
LA, LH, MA, MH, MHF, PA (1600)
R, J, T3
2
2
2
2,3
2,3
LA, MA
2
QG (225)
LH, MG, MH, PG, PA (1600), RG (2000) 2,3
2
QJ (225)
MJ, MHF, PJ, PH (1600), RJ (2000) 2,3
R, J, T6, T3, L (1200)
QO-VH
2
125
QD
2
225
QD
2
225
QD
2
225
70
125 ¶
QOT
20
QO
QOT
70
20
125 ¶
QO
70
125 ¶
QOT
20
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series ¶ Load centers with 100 A mains rating are
connected circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than limited to 100 A maximum integral main
circuit breaker and 70 A maximum branch
that of the circuit breaker with the lowest interrupting rating presently installed. See panelboard wiring diagram for
circuit breaker.
circuit breaker types.
240 Vac, 3-Phase 3 W
Grounded "B" phase.
© 2003–2004 Schneider Electric All Rights Reserved
See circuit breaker for voltage and
interrupting rating.
Catalog Designation QO includes QO-GFI,
QO-EPD, QO-PL, QO-AS, and QO-AFI
circuit breakers.
5
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
How to Read the Three-Tier Series Rating Label
Figure 8:
4100DB0301R9/04
09/2004
Read the label from left to right. Select the appropriate short circuit current
rating, and then read across the row to select main disconnect, tenant circuit
breaker and load center circuit breakers. See example below in Figure 8.
Selecting Short Circuit Current Rating
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
42,000 at 240
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
50
100
30
50
200
50
HOMT
50
30
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
65 kA
HOM §
HOMT
HOM §
10 kA
The highlighted portion in the label above
depicts the system shown to the left.
LHP36400
QDP22100TM
HOM 30 A
EZM Main Breaker Device
(EZM3400CB) Feeding
EZM Branch Device
(EZM312225)
Downstream
Homeline Load Center
(HOM20L125C)
The same series rating information is supplied on all convertible main QO
and Homeline load centers covers. The figures below explain which portions
of the label apply to the different types of end use equipment.
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
HOM §
50
100
HOMT
30
HOM §
HOMT
50
30
50
200
50
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
For Three-Phase QO Load Centers
6
© 2003–2004 Schneider Electric All Rights Reserved
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
4100DB0301R9/04
09/2004
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
HOM §
50
100
HOMT
HOM §
HOMT
30
50
200
50
50
30
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
For Single-Phase Convertible Main QO Load Centers Protected with QO-VH Tenant Circuit Breaker
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
HOM §
50
HOMT
30
50
HOM §
HOMT
50
30
200
50
100
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
For Single-Phase Convertible Main QO Load Centers Protected with 2-Pole QD Tenant Circuit Breaker
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
HOM §
50
100
HOMT
HOM §
HOMT
30
50
200
50
50
30
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
For Homeline Convertible Main Load Centers Protected with QO-VH Tenant Circuit Breaker
© 2003–2004 Schneider Electric All Rights Reserved
7
Square D® Load Center Short-Circuit Current Ratings
Data Bulletin
4100DB0301R9/04
09/2004
THREE-TIER SERIES CONNECTED SHORT CIRCUIT CURRENT RATING
Interrupting Rating RMS
Symmetrical Amperes
at_____Vac Max.
42,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240
42,000 at 240
65,000 at 240
100,000 at 240, 2-Pole
65,000 at 240, 3-Pole
100,000 at 208Y/120, 3-Pole
Line Side SQUARE D Circuit Breaker
Catalog Designation or Fuse Class
(Maximum A Rating)
LA, LH, MA, MH, MHF, PA (1600),
Class R, J, T3
LA, MA, Class T3
LH, MH, PA (1600)
MHF, Class R, J, T3 (800)
LA, MA
LH, MG, MH, PG, PA (1600), RG (2000)
MJ, MHF, PJ, PH (1600), RJ (2000),
Class R, J, T6, T3, L (1200)
SQUARE D Branch Circuit Breakers
QO Load Centers
Homeline Load Centers
SQUARE D Tenant Circuit Breaker
Poles
(Integral or Remote)
Catalog Designation
(Max. A rating)
Poles
2,3
QO-VH (125)
2
2,3
QO-VH (125)
2
2,3
Max. Ampere Rating
Max. Ampere Rating
Catalog
Catalog
Designation 1-Pole 2-Pole 3-Pole Designation 1-Pole
2-Pole
70
100
QO
QOT
20
2
QO
QOT
70
20
200
QO
QO-VH
QO-H
70
125
3
QD (225)
The Short Circuit Current Rating is equal to the lowest interrupting rating of any circuit breaker installed or combination series connected
circuit breaker. Additional or replacement circuit breaker(s) MUST have an interrupting rating equal to or greater than that of the circuit breaker
with the lowest interrupting rating presently installed.
See panelboard interior for circuit breaker types that may be used in this panelboard. See circuit breaker for voltage and interrupting rating.
HOM §
50
HOMT
30
50
HOM §
HOMT
50
30
200
50
100
30
100
100
Catalog Designation QO includes § Catalog Designation HOM
QO-GFI, QO-EPD, QO-PL, QO-AS, includes HOM-GFI, HOM-EPD,
and HOM-AFI circuit breakers.
and QO-AFI circuit breakers.
100 A maximum branch circuit breaker in load centers with 125 A
maximum mains rating.
For Homeline Convertible Main Load Centers Protected with 2-Pole QD Tenant Circuit Breaker
NEC Requirements
Figure 9:
Example of Label Provided
Two sections of the NEC address markings of series ratings: Section
110.22 and Section 240.86(a).
Per Section 110.22, the equipment must be legibly marked in the field to
indicate the equipment has been applied with a series combination rating.
The intent of this section is to alert the installer that the circuit breakers were
installed based on a series rating, and to mark the equipment with the short
circuit current rating being applied in the series combination.
Square D provides a label for this purpose with all MP Meter-Pak™
Meter Centers and EZ Meter-Pak® Meter Center Branch Devices (See
Figure 9). The label is not applied by Square D, but is provided loose in
these devices for application when series ratings are applied by the installer.
CAUTION / PRECAUCION
SERIES COMBINATION SYSTEM
SISTEMA COMBINADO EN SERIE
RATED _____________ AMPERES.
CORRIENTE NOMINAL: _________ A
ID E N T I F I E D R E P L A C E M E N T ES NECESARIO IDENTIFICAR EL
COMPONENTE DE REPUESTO
COMPONENTS REQUIRED.
Additional or replacement circuit breakers must be
manufactured by Square D and have a short circuit
current rating equal to or greater than that of the
circuit breaker(s) presently installed. Refer to
additional information provided with this equipment.
Failure to do so can result in electrical
explosion and fire.
Los interruptores automáticos adicionales o de
repuesto deben ser productos de Square D; su
corriente nominal de cortocircuito debe ser igual
que o mayor que la de los interruptores
automáticos actualmente instalados. Consulte la
información adicional incluida con el equipo.
El incumplimiento de esta instrucción puede
causar una explosión eléctrica e incendio.
Section 240.86(a) requires that the series combination of overcurrent
protective devices be marked on the end use equipment. This marking is
applied by the manufacturers of switchboards, panelboards, load centers,
etc. Square D marks load center enclosures and covers with series ratings
per Figures 1, 4 and 4a.
Conclusion
Schneider Electric USA
1601 Mercer Road
Lexington, KY 40511 USA
1-888-SquareD (1-888-778-2733)
www.SquareD.com
A series rated system is an affordable, viable alternative to a fully rated
system. Series ratings can be two-tiered or multi-tiered, depending on the
levels of overcurrent protection tested and certified. Series ratings include
circuit breaker/circuit breaker combinations and also fuse/circuit breaker
combinations, but the furthest load side overcurrent protective device is
always a circuit breaker. Overcurrent protective device combinations used
in series rated systems should be marked on the end use equipment by the
electrical distribution product manufacturer. Equipment installed as part of a
series rated system must be marked in the field to indicate the short circuit
current rating being applied in the series combination.
Electrical equipment should be installed, operated, serviced, and maintained only by
qualified personnel. No responsibility is assumed by Schneider Electric for any
consequences arising out of the use of this material.
© 2003–2004 Schneider Electric All Rights Reserved