Designed for high-capacity power systems, the Siemens LGB3K070B is a 70-amp, 3-pole molded case circuit breaker. It utilizes proven thermal-magnetic trip technology to protect commercial and industrial circuits from overloads and short circuits. This GB frame breaker mounts securely into Siemens P1, P2, and P3 panelboards via a bolt-on connection. For modern upgrades, it is replaced by the 3VA5170-6ED31-0AA0, which necessitates a specific strap kit for P1 enclosures.
HACR Rated, High Interrupting Capacity, Reverse Feed
Product FAQs
6 answers
Which panelboards are compatible with the Siemens LGB3K070B circuit breaker?
This breaker is designed specifically for Siemens P1, P2, and P3 distribution panelboards. It bolts directly to the panel bus and requires the appropriate deadfront filler plates if it does not completely fill the unit space.
What wire sizes and materials are accepted by the lugs on the LGB3K070B?
The factory-installed load side lugs accept 8 to 1/0 AWG copper conductors or 8 to 2/0 AWG aluminum conductors. Ensure you use 75-degree Celsius rated wire for proper installation.
Can the LGB3K070B be used in DC control systems?
Yes, in addition to its AC ratings, this breaker is rated for 125/250VDC applications, making it suitable for specific direct current control or battery systems. It provides a 14kA interrupting capacity at this DC voltage.
What type of protection does the LI trip function provide?
The LI designation means the breaker uses a thermal-magnetic trip unit to provide Long-Time (thermal) protection against continuous overloads and Instantaneous (magnetic) protection against short circuits. Both the thermal and magnetic trip points are fixed.
Does the LGB3K070B require a mounting adapter for installation?
No adapter is needed when installing this breaker into compatible Siemens P1, P2, or P3 panelboards. It features a bolt-on design that connects directly to the panel busbars.
Can I mount the LGB3K070B on a standard DIN rail?
No. While some Siemens G-frame breakers (like the GG frame) are DIN rail mountable, the LGB frame is specifically configured with line-end connections for bolt-on panelboard mounting only.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 1 review.
Siemens LGB3B045B - 45A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/27/26
Siemens 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.