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Siemens JL3B300 Molded Case Circuit Breaker
- 300A
- 3 Pole
- Bolt-On
Siemens
JL3B300
Molded Case Circuit Breaker
Brand
Siemens
SKU
JL3B300
Quantity
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Siemens JL3B300 - 300A 3 Pole Molded Case Circuit Breaker
Re-Certified
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Description
Part of the legacy J-Frame series, the Siemens JL3B300 is a 3-pole, 300A molded case circuit breaker designed for industrial power distribution. It provides robust thermal-magnetic protection with fixed thermal and adjustable magnetic trip settings. This unit bolts into Siemens P4 and P5 panelboards, switchboards, and legacy ITE FC-1 panelboards. Rated for 35kA at 480VAC, this HACR-rated breaker features an interchangeable trip unit and can be substituted with the newer JD63B300 model.Specifications
| Brand | Siemens |
|---|---|
| Part Number | JL3B300-R |
| Series | JL |
| Amperage | 300A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 35kA @ 480VAC, 25kA @ 600VAC, 30kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Siemens P4, P5 Panelboards, Switchboards, Motor Control Centers, Legacy ITE FC-1 Panelboards |
| Wire Gauge | 3/0 AWG - 500 kcmil |
| 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, Lug Kits |
|---|---|
| Accessories | Lugs Not Included |
| Standards | UL 489, CSA C22.2 No. 5, NEMA AB-1 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Interchangeable Trip Unit, Trip-Free Mechanism |
Product FAQs
8 answersWhich panelboards are compatible with the JL3B300 breaker?
This bolt-on breaker is designed for installation in Siemens P4 and P5 panelboards, switchboards, and motor control centers. It is also backward compatible with legacy ITE FC-1 panelboards.
Is there a modern direct replacement for the legacy JL3B300?
Yes, the legacy JL3B300 can typically be substituted with the newer Siemens JD63B300 molded case circuit breaker, which shares the same physical footprint and J-Frame specifications.
What wire gauge range is accepted by the lugs on this 300A breaker?
When equipped with standard lugs, the JL3B300 accepts copper or aluminum conductors ranging from 3/0 AWG to 500 kcmil.
Are the trip settings on the JL3B300 adjustable?
This breaker features a thermal-magnetic trip unit with a fixed thermal element for long-time overload protection and an adjustable magnetic element for instantaneous short-circuit protection.
Can the JL3B300 be used in DC power systems?
Yes, this breaker is rated for use in DC applications up to 250VDC, providing an interrupting capacity of 30kA.
What are the AC interrupting ratings for the JL3B300 across different voltage levels?
For AC systems, this breaker delivers an interrupting capacity of 65kA at 240V, 35kA at 480V, and 25kA at 600V, allowing it to handle varying fault current requirements in industrial facilities.
Does this breaker feature an interchangeable trip unit?
Yes, the JL3B300 is built with an interchangeable trip unit design, allowing the thermal-magnetic trip block to be swapped or upgraded without replacing the entire breaker frame.
Is the JL3B300 suitable for HVAC applications?
Yes, this breaker is HACR rated, meaning it is certified for use with heating, air conditioning, and refrigeration equipment.
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