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Siemens KM3B400 Molded Case Circuit Breaker
- 400A
- 3 Pole
- Bolt-On
Siemens
KM3B400
Molded Case Circuit Breaker
Brand
Siemens
SKU
KM3B400
Quantity
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Siemens KM3B400 - 400A 3 Pole Molded Case Circuit Breaker
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Description
Designed to handle demanding electrical loads, the Siemens KM3B400 is a 400A, 3-pole MCCB. It operates at up to 600VAC and utilizes fixed thermal and adjustable magnetic trip settings for precise overcurrent protection. This legacy bolt-on breaker is compatible with Siemens P4 and P5 panelboards, along with SB1, SB2, and SB3 switchboards. Rated at 50kAIC at 480VAC, the unit features a trip-free mechanism and is HACR rated. It accommodates 1/0 AWG to 500 kcmil copper or aluminum wiring.Specifications
| Brand | Siemens |
|---|---|
| Part Number | KM3B400-R |
| Series | KM |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 600VAC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 50kA @ 480VAC, 22kA @ 600VAC |
| Frame Type | KM |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P4, P5, S4, S5 Panelboards, SB1, SB2, SB3 Switchboards, Motor Control Centers |
| Wire Gauge | 1/0 AWG - 500 kcmil (Cu/Al) |
| Max Wire | 500 kcmil |
| Min Wire | 1/0 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Interchangeable Trip Unit, Trip-Free Mechanism, HACR Rated |
Product FAQs
6 answersWhich Siemens panelboards and switchboards are compatible with the KM3B400 breaker?
The KM3B400 is designed for use in Siemens P4, P5, S4, and S5 panelboards, as well as SB1, SB2, and SB3 switchboards and compatible Motor Control Centers.
What wire sizes and materials are accepted by the standard lugs on this breaker?
The standard lugs on the KM3B400 accept copper or aluminum conductors ranging from 1/0 AWG to 500 kcmil.
How does the adjustable magnetic trip function operate on the KM3B400?
This breaker features a thermal-magnetic trip unit with a fixed thermal element for overload protection and an adjustable magnetic element. The adjustable magnetic setting allows you to fine-tune the instantaneous short-circuit pickup to coordinate with downstream devices or handle motor inrush currents.
Can the Siemens KM3B400 replace older ITE brand breakers?
Yes, Siemens acquired ITE, and the KM3B400 serves as the direct replacement for legacy ITE KM-frame 400A breakers sharing the same catalog number.
What does the LI trip function code indicate on this breaker?
The LI designation means the trip unit provides Long-Time (L) and Instantaneous (I) protection. Long-Time handles sustained overloads, while Instantaneous provides immediate tripping during severe short circuits.
How does the KM3B400 mount into the panel?
It utilizes a bolt-on connection type, requiring it to be physically bolted to the panelboard or switchboard bus for a secure, high-capacity electrical connection.
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