Free Shipping Over $99
Free Shipping Over $99
Free Shipping Over $99
Free Shipping Over $99
Eaton / Cutler-Hammer BR340ST Miniature Circuit Breaker
- 40A
- 3 Pole
- Plug-On
Eaton / Cutler-Hammer
BR340ST
Miniature Circuit Breaker
Brand
Eaton / Cutler-Hammer
SKU
BR340ST
Quantity
Shop with Confidence
Add an extra year of protection in your cart.
Eaton / Cutler-Hammer BR340ST - 40A 3 Pole Miniature Circuit Breaker
New
Quantity
Similar Items
30A 3 Pole Miniature Circuit Breaker
60A 3 Pole Miniature Circuit Breaker
20A 3 Pole Miniature Circuit Breaker
Description
Engineered for commercial and industrial applications, this 40-amp, three-pole device features an integrated 120VAC shunt trip mechanism for remote power interruption. It mounts into standard Eaton Type BR load centers and is compatible with legacy Cutler-Hammer enclosures. Delivering a 10kAIC rating at 240VAC, the thermal-magnetic design provides reliable long-time and instantaneous protection. The factory-installed shunt trip makes it ideal for emergency stop or automated control systems.Specifications
| Brand | Eaton / Cutler-Hammer |
|---|---|
| Series | BR |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC |
| Frame Type | BR |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | Type BR Load Centers |
| Wire Gauge | 14-4 AWG (Cu/Al) |
| Max Wire | 4 AWG |
| Min Wire | 14 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment |
|---|---|
| Accessories | Shunt Trip |
| Standards | UL 489, Federal Specification W-C375 |
| Approval | UL |
| Temp Rating | 60C, 75C |
| Construction Features | Common Trip, HACR Rated |
Product FAQs
6 answersWhat panels are compatible with the BR340ST circuit breaker?
This breaker is designed for use in 3-phase Eaton and legacy Cutler-Hammer Type BR load centers. It utilizes a standard plug-on mounting configuration.
Can this 3-pole breaker be installed in a single-phase panel?
No. The BR340ST is a 3-pole breaker designed exclusively for 3-phase Type BR load centers. It requires three hot bus bars to mount and function correctly.
How do I wire the shunt trip module on this breaker?
The shunt trip features two non-polarity sensitive leads. Connect one lead to your 120VAC control voltage source and the other to a normally open momentary contact, such as a push button or fire alarm relay, to complete the circuit.
What is the purpose of the factory-installed shunt trip?
The shunt trip mechanism allows the breaker to be opened remotely by applying an external 120VAC control voltage. It is typically used for emergency stop applications, equipment protection, or integration with fire alarm panels.
Can I apply a continuous voltage to the shunt trip coil?
No. The shunt trip requires a momentary 120VAC signal to operate safely. Applying a continuous control voltage will cause the internal coil to overheat and burn out.
Is the Eaton BR340ST a direct replacement for the Cutler-Hammer BR340ST?
Yes. Eaton acquired Cutler-Hammer and continues to manufacture Type BR circuit breakers under the Eaton name. The BR340ST is the direct replacement for legacy Cutler-Hammer breakers sharing the same catalog number.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
100 SuperPoints = $1 off.
Warranties
Add an extra year of protection
60-Day Warranty
Your purchase includes 60 days of SuperBreakers warranty coverage.
Add a 1-year warranty extension in your cart.
Get a Quote
Don’t see what you’re looking for?
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.
Same Day Shipping
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 70 reviews.
Reviews Summary
Generated by AI from 96 most recent customer reviews
Last updated 8/15/25
Customers say these circuit breakers arrive quickly and fit their needs perfectly. Many reviews mention competitive pricing and reliable availability, particularly for hard-to-find models. The products consistently meet expectations for installation and functionality. Reviews frequently note the precise fit and immediate operation of these breakers. Some users appreciate the option of both new and refurbished units.
Search
Rating
70 reviews
- DCDavid C.Verified BuyerReviewingEaton / Cutler-Hammer BR230 - 30A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/25/26as described
delivered on time as described
- DCDavid C.Verified BuyerReviewingEaton / Cutler-Hammer BR120 - 20A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/25/26as described
delivered on time as described
- DCDavid C.Verified BuyerReviewingEaton / Cutler-Hammer BR1515 - 15/15A Tandem Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/25/26as described
delivered on time as described
- DCDavid C.Verified BuyerReviewingEaton / Cutler-Hammer BR2020 - 20/20A Tandem Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/25/26as described
delivered on time as described
- MPMichael P.Verified BuyerReviewingEaton / Cutler-Hammer BR1520 - 15/20A Tandem Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/5/26An excellent business
In this day and age it can be a challenge at times finding a reputable business that fills your order correctly and at the right price and without delay. I am very pleased with your service. Thank you.