Designed for demanding industrial applications, this 2-pole, 125A molded case circuit breaker provides robust thermal-magnetic protection. Rated for 240VAC, it features a fixed trip unit with long-time and instantaneous (LI) functions. The bolt-on configuration installs into Siemens panelboards and switchboards, serving as a replacement for legacy QJ frames (now replaced by the QR22B125H). It boasts a high 42kAIC interrupting rating, reverse-feed capability, and HACR certification.
HACR Rated, Reverse Feed, Non-Interchangeable Trip, Trip-Free Mechanism, Common Trip, High Interrupting Capacity
Product FAQs
8 answers
Which panelboards accept the Siemens QJ22B125H circuit breaker?
This bolt-on QJ frame breaker is designed for installation in Siemens and legacy ITE panelboards and switchboards. Always verify your specific panel's labeling to ensure QJ or QJ2H frame breakers are listed as acceptable branch or main devices.
What is the QR frame replacement for the QJ22B125H?
Siemens has transitioned the legacy QJ frame to the newer QR frame series. The direct replacement for this 125A, 42kAIC breaker is the QR22B125H. The QR frame shares the same physical footprint and panelboard compatibility but adds a push-to-trip button and support for field-installable accessories.
Can internal accessories be field-installed on the QJ22B125H?
No, internal accessories like shunt trips or auxiliary switches must be factory-installed on legacy QJ frame breakers. If you require field-installable accessories, you will need to use the newer QR frame equivalent, the QR22B125H.
What applications is the 42kAIC rating on the QJ22B125H suitable for?
The 42kAIC rating at 240VAC indicates a high interrupting capacity. This makes the breaker suitable for commercial and industrial distribution systems where the available fault current exceeds standard 10kAIC or 22kAIC thresholds.
Is the QJ22B125H suitable for HVAC equipment protection?
Yes, this breaker is HACR rated, meaning it has been tested and approved for the specific inrush currents and operational demands of Heating, Air Conditioning, and Refrigeration equipment.
Can the Siemens QJ22B125H be reverse fed?
Yes, this thermal-magnetic circuit breaker supports reverse feeding. It can be back-fed in compatible panelboards or enclosures, provided the installation complies with local electrical codes and panelboard labeling.
What are the lug wire size requirements for the QJ22B125H?
The factory lugs accept 6 AWG to 300 kcmil copper (Cu) or 4 AWG to 300 kcmil aluminum (Al) conductors. Ensure all terminations are torqued to the specifications printed directly on the breaker label to prevent high-resistance connections.
What type of trip unit does the QJ22B125H use?
It features a fixed thermal-magnetic trip unit with long-time and instantaneous (LI) functions. The thermal element provides overload protection, while the magnetic element protects against short circuits.
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Reviews
Review summary
Customers rate this product 4.8 out of 5 based on 10 reviews.
Siemens QJ23B125 - 125A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/11/26
Breaker
Perfect
TN
Timothy N.
Verified Buyer
Reviewing
Siemens QJ23B200 - 200A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
7/27/26
10% off
Arrived on time, worked when turned on
WK
Willie K.
Verified Buyer
Reviewing
Siemens QJ23B150 - 150A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 4 out of 5 stars
7/22/26
Breaker
The Breaker arrive fast and in good condition however when I looked at the specs it was not the correct one.
PG
Phil G.
Verified Buyer
Reviewing
Siemens QJ23B200 - 200A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
3/3/26
Great Service
I was in a bind for this breaker that was for an elevator, and Nick got me all the components even though their blizzard! Will use them for all my specialty breakers.
VC
Vladimir C.
Verified Buyer
Reviewing
Siemens QJ22B200 - 200A 2 Pole Molded Case Circuit Breaker
I recommend this product
Rated 4 out of 5 stars
12/10/25
4 start
The breaker was it perfect match.,but it was missing the two top bolts.