Engineered for commercial and industrial power distribution, this 125-amp Siemens component features a factory-installed auxiliary switch (1A/1B) for remote status signaling. It serves as a robust thermal-magnetic solution for 240VAC systems requiring standard 10kA interrupting capacity. Designed to integrate seamlessly into Siemens P1, P2, and P3 panelboards, it utilizes a secure bolt-on mounting style.
What does the A01 suffix indicate on the QJ23B125A01?
The A01 suffix designates that this breaker is factory-equipped with a 1A/1B auxiliary switch. This provides one normally open and one normally closed contact for remote breaker status indication.
Which Siemens panelboards accept this QJ2 series breaker?
This bolt-on breaker is designed for installation in Siemens P1, P2, and P3 panelboards, as well as compatible Siemens switchboards and motor control centers.
Does this breaker include both line and load side lugs?
No. Because this is a bolt-on breaker, the line side bolts directly to the panel bus. It only includes lugs on the load side for your outgoing wire connections.
What wire sizes are supported by the load side lugs?
The factory-installed load side lugs accept 6 AWG to 300 kcmil copper wire, or 4 AWG to 300 kcmil aluminum wire.
Can I use the QJ23B125A01 to replace a standard QJ23B125?
Yes. The QJ23B125A01 shares the exact same physical dimensions, mounting style, and electrical ratings as the standard QJ23B125. If your system does not require the included auxiliary switch, the control wires can simply be left disconnected.
Is this breaker suitable for 480V systems?
No. The QJ2 series is strictly rated for a maximum of 240V AC. It cannot be safely used in 480V or 600V applications.
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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.