Siemens LGB3K040B Molded Case Circuit Breaker
- 40A
- 3 Pole
- Bolt-On
Quantity
Siemens LGB3K040B - 40A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Engineered for robust industrial use, the Siemens LGB3K040B is a 40-amp, 3-pole MCCB from the Sentron GB/GG frame group. The breaker mounts into Siemens P1, P2, and P3 panelboards via a sturdy bolt-on connection. If replacing this exact unit, the modern substitute is the 3VA5140-6ED31-0AA0, which requires a specific mounting strap kit. With an impressive 65 kAIC rating at 480Y/277V, it safely clears severe electrical faults. It is both HACR and HID rated with a trip-free mechanism.Specifications
| Brand | Siemens |
|---|---|
| Series | LGB |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480Y/277VAC, 600Y/347VAC, 125/250VDC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480Y/277VAC, 25kA @ 600Y/347VAC, 14kA @ 125/250VDC |
| Frame Type | LGB |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3 Panelboards |
| Wire Gauge | 8-1/0 AWG (Cu), 8-2/0 AWG (Al) |
| Max Wire | 1/0 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment |
|---|---|
| Accessories | Load Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489 |
| Approval | CE, CSA, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, HID Rated, Reverse Feed, Non-Interchangeable Trip, Quick-Make/Quick-Break, Trip-Free Mechanism, Common Trip |
Product FAQs
7 answersWhich panelboards are compatible with the Siemens LGB3K040B?
This bolt-on breaker is designed specifically for use in Siemens P1, P2, and P3 series panelboards. It mounts directly to the panel bus using standard bolt-on connections.
What wire sizes and materials are accepted by the LGB3K040B terminals?
The factory-installed lugs accept 8 AWG to 1/0 AWG copper wire, or 8 AWG to 2/0 AWG aluminum wire. Always ensure proper torque specifications are followed during installation as listed on the breaker label.
Can the LGB3K040B be used in DC voltage applications?
Yes, this breaker is rated for use in DC systems up to 125/250VDC, providing a 14kA interrupting capacity for direct current applications.
What does the LI trip function indicate on this Sentron series breaker?
The LI designation means the breaker features Long-Time and Instantaneous trip functions. It uses a fixed thermal element for overload protection (Long-Time) and a fixed magnetic element for short-circuit protection (Instantaneous).
Is the LGB3K040B a direct replacement for older Siemens or ITE breakers?
The LGB frame is part of the modern Siemens Sentron family. It is commonly used to replace older GB or GG frame breakers in existing P1, P2, or P3 panelboards, provided the panel bus and mounting hardware match.
Does this breaker require a specific mounting hardware kit?
When installing in Siemens P1, P2, or P3 panelboards, you must use the appropriate strap kits or mounting hardware designed for the specific panelboard type and GB/GG frame breakers.
How does the interrupting rating change depending on the system voltage?
The breaker provides a 100kAIC rating at 240VAC, which drops to 65kAIC at 480VAC and 25kAIC at 600VAC. You must verify that the available fault current at your installation point does not exceed these voltage-specific ratings.
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 5.0 out of 5 based on 1 review.
- RSRon S.Verified BuyerReviewingSiemens LGB3B045B - 45A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/27/26Siemens Breaker
The breaker was exactly what I needed, and it came within a couple days. The price was in line of what it should’ve been. This was my third purchase from Super Breakers. I will definitely use them again in the future.