Siemens NEG3B050L Molded Case Circuit Breaker
- 50A
- 3 Pole
- Unit Mount
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Siemens NEG3B050L - 50A 3 Pole Molded Case Circuit Breaker
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Description
The Siemens NEG3B050L is a 50A, 3-pole molded case circuit breaker from the VL Series. Built for commercial and industrial applications, it provides reliable thermal-magnetic protection with long-time and instantaneous (LI) trip functions. Designed for unit mounting, it installs into Siemens VL enclosures and panelboards. This model includes line and load lugs and is replaced by the 3VA5150-5ED31-0AA0. Rated 85kAIC at 240V, the NEG frame features a current-limiting, HACR-rated design.Specifications
| Brand | Siemens |
|---|---|
| Part Number | NEG3B050L |
| Series | NEG |
| Amperage | 50A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600Y/347VAC, 500VDC |
| Phase | 3 |
| AIC Rating | 85kA @ 240VAC, 35kA @ 480VAC, 22kA @ 600Y/347VAC, 30kA @ 500VDC |
| Frame Type | NEG |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens VL Series Enclosures, Panelboards, Switchboards |
| Wire Gauge | 8 AWG - 1/0 AWG (Cu), 8 AWG - 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, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Line and Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, NOM, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Current Limiting, Reverse Feed |
Product FAQs
7 answersWhat do the characters in the NEG3B050L catalog number signify?
In the Siemens VL Series nomenclature, "N" indicates the normal interrupting class, "EG" is the frame size, "3" stands for 3 poles, "B" specifies a thermal-magnetic trip unit, "050" represents the 50A rating, and the "L" suffix means the breaker is supplied with factory-installed line and load lugs.
How does the trip unit on the NEG3B050L operate?
The NEG3B050L uses a thermal-magnetic trip unit (Model 525) that provides fixed thermal protection for overloads and adjustable magnetic protection for short circuits, allowing for better coordination with downstream electrical devices.
Can the NEG3B050L be used in DC electrical systems?
Yes, this thermal-magnetic breaker is rated for use in DC applications up to 500VDC, where it provides a 30kA interrupting capacity. For 500VDC ungrounded systems, Siemens recommends connecting the power supply in a series zig-zag configuration across all three poles to ensure uniform voltage distribution.
What enclosures and panels are compatible with the NEG3B050L?
This unit-mount breaker is designed for use in Siemens VL Series enclosures, panelboards, and switchboards.
What are the torque specifications for the factory lugs on the NEG3B050L?
For the standard factory lugs, torque 8 AWG wire to 40 lb-in, 6 AWG to 4 AWG wire to 45 lb-in, and 3 AWG through 1/0 AWG copper (or up to 2/0 AWG aluminum) wire to 50 lb-in.
Does the NEG3B050L support field-installable internal accessories?
Yes, Siemens VL EG-frame 3-pole breakers feature internal accessory pockets that accept field-installable components like shunt trips, undervoltage releases (UVR), and auxiliary or alarm switches.
Does the NEG3B050L have a push-to-trip feature?
Yes, Siemens VL Series breakers include a push-to-trip button on the face of the breaker. This allows you to manually test the tripping mechanism and ensure the breaker is functioning correctly before or after installation.
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