Siemens mp120u 20A 120V 1-pole Miniature Circuit Breaker

Product Description

The SIEMENS mp120u is a single-pole, thermal magnetic miniature circuit breaker rated for 20 amps at 120 volts AC. It provides overcurrent and short-circuit protection in residential and light commercial electrical panels. The plug-in mounting style simplifies installation in compatible load centers, and lug-style load terminals accept standard branch-circuit conductors. With a 10 kA interrupting rating (IR), this breaker is suited for typical residential service entrance panels where available fault current falls within that threshold. Licensed electricians install this breaker as part of branch-circuit wiring in new construction, panel upgrades, or service calls.

The mp120u belongs to the Murray Speedfax MP series and is designed for single-pole, 120-volt branch circuits. Typical applications include lighting circuits, receptacle circuits, and small appliance loads in residential panels. It is also used in light commercial applications where a plug-in style breaker is called for and the panel accepts Murray or compatible Siemens load centers. The thermal magnetic trip mechanism responds to both sustained overloads and instantaneous short-circuit events.

Key Features

• Thermal magnetic trip mechanism provides dual protection against overloads and short circuits
• 20-amp rating suitable for standard 120-volt branch circuits
• 10 kA interrupting rating meets the demands of most residential service panels
• Plug-in mounting for fast, tool-free installation into compatible load centers
• Lug-style load terminal accommodates standard branch-circuit wiring
• Single-pole, 1-inch wide form factor fits standard breaker slots

Compatibility

Part of the Murray Speedfax MP series. Designed as a plug-in style replacement or new-installation breaker for load centers that accept Murray and compatible Siemens miniature circuit breakers.

Installation Notes

Installation must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. De-energize the panel and verify absence of voltage with a meter before handling any breaker or wiring. Seat the plug-in breaker firmly into the bus bar before securing conductors to the load terminal. Do not exceed the conductor size or ampacity limits stated on the breaker label or in the load center instructions.

Technical Specifications

• Type: Thermal Magnetic Miniature Circuit Breaker
• Poles: 1P
• Amperage: 20A
• Voltage: 120V AC
• Interrupting Rating: 10 kA IR
• Mounting: Plug-In
• Load Terminal: Lug
• Dimensions (H x W x D): 3.13 inches x 1 inch x 3 inches

Standard Information

• Brand: SIEMENS
• Manufacturer Part Number: mp120u