Datasheet Content
QO® and QOB Miniature Circuit
Breakers with Ground Fault Protection
Integrated design combines UL-approved circuit breaker with 5 mA,
30 mA or 100 mA ground fault protection
Ground faults can occur when electrical equipment is worn, defective or accidentally misused.
Square D® QO and QOB miniature circuit breakers with ground fault protection provide load level
detection that isolates only the affected circuit when a ground leakage occurs. Applying branch
breakers with integral ground fault protection allows users to quickly identify the ground leakage’s
current location and address the problem before it escalates to hazardous levels.
Square D QO EPD 3-pole Square D QO and QOB miniature circuit breakers with ground fault protection provide enhanced
Miniature Circuit Breaker
protection of a system’s wiring and sensitive electronic components. Low levels of fault current
can injure or harm personnel and damage sensitive electronic equipment yet remain insufficient to
operate the thermal-magnetic functions of the circuit breaker.
A ground fault exists when an unintended path is established between the normal current carrying
conductors and metallic or conductive surfaces, which are bonded to or in direct contact with
earth. Ground faults can initially conduct only a low level of current flow that is well below the
thermal ampere frame rating of the protective circuit breaker. However, when a ground fault
continues undetected, it can escalate causing significant heat and mechanical damage. Sensing
and interrupting the flow of low level, phase-to-ground faults provides enhanced protection of
personnel and equipment.
In an integrated design, the Square D QO and QOB miniature circuit breakers with ground fault
protection provide conventional UL 489-listed circuit breakers with built-in ground fault sensors.
No separate modules or devices are required. Three levels of ground fault protection are available
to meet your specific application needs. The QO and QOB ground fault circuit interrupter (QOB
GFI) meets the UL definition for people protection with the ground fault protection set at 5 mA.
For equipment protection, Square D QO and QOB equipment protection devices (QOB EPD) are
available with either 30 mA or 100 mA ground fault protection.
Improve system Save space and Standardize
reliability and safety installation time equipment designs
More than 90% of short circuits are initiated by ground
faults (also called earth leakage or residual current).
Apply Square D QO and QOB ground fault interrupters
and equipment protection devices to maximize
continuity of power distribution with load level protection
while only isolating the affected circuit.
Improve system reliability Save space and installation time
and safety • Ground fault protection integrated into
• Load level ground fault detection maximizes the UL 489-listed circuit breaker eliminates the
continuity of power distribution by isolating need for external current transformers or
only the affected circuit when a ground add-on modules
leakage occurs • Line-powered electronics eliminate the need
• Low level ground fault sensing at 5 mA, for a control power transformer
30 mA or 100 mA detects load level ground
faults and isolates the circuit before hazardous
levels occur Standardize equipment designs
• Square D QO and QOB EPD devices are
• Detecting low level faults before they escalate
compatible with standard NQ panelboards and
to levels that can cause excessive equipment
QO load centers
damage reduces system downtime
• Load level ground fault protection reduces the
time required to troubleshoot the cause of the
ground fault by isolating the load where the
ground leakage has occurred
• Ground fault push-to-test feature confirms if
the internal ground fault circuitry is working
• An optional IP20 rated terminal shield on
the load end of the circuit breaker enhances
protection (this accessory is infrared
compatible to facilitate thermal scanning)
Product specifications
Voltage 208Y/120 Vac or 240 Vac
Current 15 – 60 A
AIR 10 kA
Poles 1-, 2- or 3-pole
Standards/Certifications • UL 489 for Circuit Protection • UL 943 Class A for People Protection
• UL 1053 for Ground-fault Sensing (GFI devices only)
and Relaying Equipment • CSA C22.2 (not applicable to 3-pole GFI)
Mounting Options • Line-side: Plug-on or bolt-on • Load-side: Box lug or ring terminal
Square D QO GFI 3-pole
Miniature Circuit Breaker
Conductors
Maximum conductor length is 250 feet; wire sizes for box lug include the following:
Amperage Aluminum (AWG/kcmil) Copper (AWG/kcmil)
15 – 30 #12 – #8 #14 – #8
40, 50 and 60 #12 – #4 #14 – #6
The Square D QO and QOB GFI and QO and QOB EPD product lines now include 3-pole devices.
Please reference the current versions of our Digest (Document Number 0100PL0901) and the QO and
QOB Miniature Circuit Breaker Catalog (Document Number 0730CT9801) for more information on these
product lines. For the Canadian market, the Schneider Electric Electrical Distribution Catalog (Document
Number S0110CT0901EP RO) is also available.
QOB GFI catalog numbers
All provided with 5 mA setting on ground fault sensors. Omit the “B” in the third position of the catalog
number for plug-on type.
Amperage 1-pole 2-pole 3-pole
10 kA AIR 22 kA AIR 10 kA AIR 10 kA AIR
15 QOB115GFI QOB115VHGFI QOB215GFI QOB315GFI
20 QOB120GFI QOB120VHGFI QOB220GFI QOB320GFI
25 QOB125GFI QOB125VHGFI QOB225GFI —
30 QOB130GFI QOB130VHGFI QOB230GFI QOB330GFI
40 — — QOB240GFI QOB340GFI
50 — — QOB250GFI QOB350GFI
60 — — QOB260GFI —
QOB EPD catalog numbers
All provided with an AIR of 10 kA. Omit the “B” in the third position of the catalog number for plug-on type.
Amperage 1-pole 2-pole 3-pole
30 mA 30 mA 30 mA 100 mA
15 QOB115EPD QOB215EPD QOB315EPD QOB315EPE
20 QOB120EPD QOB220EPD QOB320EPD QOB320EPE
25 QOB125EPD QOB225EPD — —
30 QOB130EPD QOB230EPD QOB330EPD QOB330EPE
40 — QOB240EPD QOB340EPD QOB340EPE
50 — QOB250EPD QOB350EPD QOB350EPE
60 — QOB260EPD — —
Factory installed accessories
Ring terminals Auxiliary and alarm switches
Replaces standard box lug with a ring 120 Vac maximum voltage, 5 A maximum load
terminal on the load side of the device
Suffix Poles Amperage Suffix Function Contact
-5237 1, 2, 3 10 – 30 -1200 Auxiliary 1A
Standard QO and QOB field- -5238 1, 2 35 – 60 -1201 Auxiliary 1B
installable accessories are also
3 35 – 50 -2100 Alarm 1A
applicable to these devices.
Dimensions
Type QO GFI and QO EPD circuit breaker: 3-pole
2.23
(56.7)
5.46 4.73
(138.6) (120.1)
With terminal cover
2.94
(74.7)
0.75 0.75
(19.1) (19.1)
Type QO GFI and QO EPD circuit breaker: 1- and 2-pole
2.91
(74)
2.31
(59)
4.12
(103)
1.49 0.744
Pigtail: 18
(457) (38) (19)
07303116…
