Siemens JKL3B300 Molded Case Circuit Breaker
- 300A
- 3 Pole
- Unit Mount
Quantity
Siemens JKL3B300 - 300A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Engineered for heavy-duty commercial and industrial applications, the Siemens JKL3B300 is a 3-pole, 300A molded case circuit breaker. This unit mount MCCB provides robust overcurrent and short-circuit protection for demanding electrical distribution systems. Designed for broad compatibility, it installs seamlessly into Siemens P4 and P5 panelboards, SB switchboards, and motor control centers. It also serves as a reliable replacement for older legacy I-T-E panelboard configurations.Specifications
| Brand | Siemens |
|---|---|
| Part Number | JKL3B300 |
| Series | JKL |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 35kA @ 480VAC, 18kA @ 600VAC |
| Frame Type | JKL |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P4 Panelboards, Siemens P5 Panelboards, Siemens SB Switchboards, Siemens Motor Control Centers, Legacy I-T-E Panelboards |
| Wire Gauge | (2) 3/0 AWG-500 kcmil (Cu/Al) |
| Max Wire | 500 kcmil |
| Min Wire | 3/0 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 | Line and Load Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5, NEMA AB-1 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Interchangeable Trip Unit, HACR Rated, Trip-Free Mechanism |
Product FAQs
5 answersWhich Siemens panelboards and switchboards are compatible with the JKL3B300?
This unit mount breaker is designed for use in Siemens P4 and P5 panelboards, SB switchboards, and Siemens Motor Control Centers. It is also backward compatible with legacy I-T-E panelboards that accept J-frame breakers.
What wire sizes do the standard lugs on the JKL3B300 accept?
The standard factory lugs accommodate two conductors per phase, ranging from 3/0 AWG to 500 kcmil for both copper and aluminum wire.
How is the trip unit configured on this JKL frame breaker?
The JKL3B300 features a thermal magnetic trip unit with fixed thermal protection for long-time overloads and an adjustable magnetic setting for instantaneous short-circuit protection.
Can the Siemens JKL3B300 replace older I-T-E branded JKL breakers?
Yes, Siemens retained the original I-T-E J-frame design. The JKL3B300 serves as a direct drop-in replacement for legacy I-T-E JKL3B300 breakers with the same physical footprint and bolt-on mounting.
Does this breaker require a specific mounting hardware kit?
As a unit mount, bolt-on circuit breaker, it requires the appropriate strap kit or mounting hardware specific to the panelboard or switchboard series where it is being installed.
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