The Square D QOB3501021 is a 3 Pole thermal magnetic molded case circuit breaker with a current rating of 50 Amps and a voltage rating of 240VAC. It has an interrupting rating of 10kAIC at 240V. The QOB3501021 has a bolt-on connection type and includes long time and instantaneous trip functions.
Shunt Trip (Factory Installed), Load Side Lugs Included
Standards
UL 489, CSA C22.2 No. 5, HACR
Approval
CSA, HACR, UL
Temp Rating
40C
Construction Features
HACR Rated, Visual Trip Indicator
Product FAQs
5 answers
What does the 1021 suffix indicate on the QOB3501021 circuit breaker?
The 1021 suffix [1.2.2] means the circuit breaker includes a factory-installed 120/240 VAC shunt trip. This accessory allows the breaker to be tripped remotely when voltage is applied to the shunt coil.
How many panel spaces does the QOB3501021 occupy?
Because the factory-installed shunt trip requires one additional pole space, this 3-pole circuit breaker will take up a total of four spaces in your NQ or NQOD panelboard.
What size wire is required for the shunt trip accessory terminals?
The shunt trip terminals on this circuit breaker accept two 14 to 12 AWG copper wires. The control voltage wires can be connected to either terminal.
Can I field-install a shunt trip on a standard QOB 3-pole breaker instead of buying this model?
No. Square D shunt trips for QO and QOB miniature circuit breakers are factory-installed only and cannot be added to an existing breaker in the field.
Can I use this bolt-on breaker in a standard QO load center?
No. Bolt-on circuit breakers (QOB series) are designed specifically for commercial and industrial NQ and NQOD panelboards. Standard residential QO load centers require plug-on circuit breakers.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
We source obsolete and hard-to-find parts every day.
Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
Expedited Shipments
Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 208 reviews.
4.9
Rated 4.9 out of 5 stars
Based on 208 reviews
5
Rated out of 5 stars
200
4
Rated out of 5 stars
6
3
Rated out of 5 stars
1
2
Rated out of 5 stars
0
1
Rated out of 5 stars
1
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 3/11/26
Customers say these electrical breakers arrive exactly as ordered and work perfectly for their intended applications. They consistently praise the competitive pricing, which many report is significantly lower than local suppliers. Fast shipping and prompt delivery are frequently highlighted, with many receiving orders within days or even next-day delivery for urgent needs. The breakers arrive well-packaged and in excellent condition. Many reviews emphasize the company's extensive inventory availability, particularly for hard-to-find breakers. One customer experienced difficulty with order cancellation and was charged a restocking fee, which caused dissatisfaction.
Square D QOB220GFI - 20A GFCI Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
10/1/26
Excellent
Excellent product and service
MR
Miguel R.
Verified Buyer
Reviewing
Square D QOB230GFI - 30A GFCI Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
10/1/26
Excellent
Excellent product and service
KH
Kristopher H.
Verified Buyer
Reviewing
Square D QOB120GFI - 20A GFCI Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/28/26
Great Price!
Great price. Fast delivery. My local electric distributor wanted double for the same breaker, so it was a no brainer to order this one. Ordered another one since with the same great service.
BL
BOOSTIX L.
Verified Buyer
Reviewing
Square D QOB220 - 20A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/17/26
QOB220
That's nice breakers!
PH
Paul H.
Verified Buyer
Reviewing
Square D QOB330 - 30A 3 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/5/26
Quick shipping and delivery
Shipped and delivered on time for installation at one of our projects. Thank you!