Send a part number, a photo, or a whole BOM — we supply it and stand behind it. Worldwide shipping to 80+ countries.

SQUARE D Panelboard Main Breaker Kit: 250 Amps - Square D Main Breaker Kits
SQUARE DSquare D Main Breaker Kits

SQUARE D Panelboard Main Breaker Kit: 250 Amps

The Square D N250MJ Panelboard Main Breaker Kit is a 250 Amp, three-phase accessory for Square D J-Frame Panelboards. It includes (2) Rail Extensions and is compatible with the JRL circuit breaker series, with a…

SKU 3G-OTH-722193

Brand
SQUARE D
Item
Panelboard Main Breaker Kit: 250 Amps
Category
Square D Main Breaker Kits
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineerMessage via Telegram
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

Technical Specifications

SQUARE D
Manufacturer Part Number
N250MJ
Type
For Use With Square D J-Frame Panelboards
Amps
250
Phase
Three
Includes
(2) Rail Extension
Frame Size
225A/J
For Use With
Square D J-Frame Panelboards
Accessory Type
Panelboard Main Breaker Kit
Compatible Circuit Breaker Series
JRL
View Full Spec Sheet

Technical Documents

No technical documents available for this product.
Request documentation
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

SQUARE D Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The Square D N250MJ Panelboard Main Breaker Kit is a 250 Amp, three-phase accessory for Square D J-Frame Panelboards. It includes (2) Rail Extensions and is compatible with the JRL circuit breaker series, with a 225A/J frame size.

Frequently Asked Questions

What is the Square D N250MJ Panelboard Main Breaker Kit used for?

The Square D N250MJ Panelboard Main Breaker Kit is used to add a 250 Amp, three-phase main breaker to Square D J-Frame Panelboards. It is compatible with the JRL circuit breaker series and includes (2) Rail Extensions for secure mounting in industrial electrical distribution systems.

What are the specifications of the Square D N250MJ Panelboard Main Breaker Kit?

The Square D N250MJ Panelboard Main Breaker Kit is rated for 250 Amps, three-phase, with a 225A/J frame size. It is designed for use with Square D J-Frame Panelboards and is compatible with the JRL circuit breaker series. The kit includes (2) Rail Extensions.

Where to buy the Square D N250MJ Panelboard Main Breaker Kit worldwide?

3G Electric supplies the Square D N250MJ Panelboard Main Breaker Kit worldwide. As a global industrial solutions provider, we handle full logistics and customs clearance to deliver this Square D accessory to your facility. Contact us for availability and delivery to your location.

How to install the Square D N250MJ Panelboard Main Breaker Kit?

Installation of the Square D N250MJ Panelboard Main Breaker Kit should follow Square D guidelines for J-Frame Panelboards. Ensure power is off, mount the kit using the included (2) Rail Extensions, and connect the JRL series breaker. Always consult a qualified electrician and refer to the manufacturer's instructions.

Used in

Common applications for SQUARE D
Commercial building electrical panels — Square D QO series plug-in circuit breakers for branch circuit protection
Industrial motor control centers — Square D QOB series bolt-on breakers in NQOD panelboards
Heating equipment installations — Square D QOU series unit-mount breakers for overcurrent protection
Outdoor electrical distribution — Square D L-Frame enclosures housing LAL/LHL breakers for 400 A service
Indoor facility power distribution — Square D Q-Frame enclosures with QBL/QDL breakers for 225 A circuits
Retrofit and replacement in existing Square D load centers — QO series breakers for 120/240V AC systems

SQUARE D Products

3G Electric supplies SQUARE D square d main breaker kits. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

You might also need

Burners & Combustion Pumps & Compressors Spare Parts All Products

More from SQUARE D

View all SQUARE D parts
Panelboard Main Breaker Kit: 225 Amps, For Use With Square D PowerPact H, J and Q-Frame Panelboards (MPN NQMB2HJ). Key specifications — Frame Size: 150A/H; Compatible Circuit Breaker Series: HGL; For Use With: Square D PowerPact H, J and Q-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 225; Includes: (13) Tapping Screws.
SQUARE D
Panelboard Main Breaker Kit: 225 Amps, For Use With Square D PowerPact H, J and Q-Frame Panelboards (MPN NQMB2HJ). Key specifications — Frame Size: 150A/H; Compatible Circuit Breaker Series: HGL; For Use With: Square D PowerPact H, J and Q-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 225; Includes: (13) Tapping Screws.
Panelboard Main Breaker Kit: 225 Amps, For Use With Square D NQ Panelboards (MPN NQMB2Q). Key specifications — Frame Size: 225A/Q; Compatible Circuit Breaker Series: QB; For Use With: Square D NQ Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 225; Includes: (1) Cover.
SQUARE D
Panelboard Main Breaker Kit: 225 Amps, For Use With Square D NQ Panelboards (MPN NQMB2Q). Key specifications — Frame Size: 225A/Q; Compatible Circuit Breaker Series: QB; For Use With: Square D NQ Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 225; Includes: (1) Cover.
Panelboard Main Breaker Kit: 400 Amps, For Use With Square D NQ Panelboards (MPN NQMB4LA). Key specifications — Frame Size: 400A/L; Compatible Circuit Breaker Series: LAL; For Use With: Square D NQ Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 400; Includes: (1) Cover.
SQUARE D
Panelboard Main Breaker Kit: 400 Amps, For Use With Square D NQ Panelboards (MPN NQMB4LA). Key specifications — Frame Size: 400A/L; Compatible Circuit Breaker Series: LAL; For Use With: Square D NQ Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 400; Includes: (1) Cover.
Panelboard Main Breaker Kit: 400 Amps, For Use With Square D L-Frame Panelboards (MPN N400M). Key specifications — Frame Size: 400A/L; Phase: Three; Compatible Circuit Breaker Series: LHL; For Use With: Square D L-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 400; Includes: (1) Screw Set.
SQUARE D
Panelboard Main Breaker Kit: 400 Amps, For Use With Square D L-Frame Panelboards (MPN N400M). Key specifications — Frame Size: 400A/L; Phase: Three; Compatible Circuit Breaker Series: LHL; For Use With: Square D L-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 400; Includes: (1) Screw Set.
Panelboard Main Breaker Kit: 150 Amps, For Use With Square D H-Frame Panelboards (MPN N150MH). Key specifications — Frame Size: 150A/H; Phase: Three; Compatible Circuit Breaker Series: HRL; For Use With: Square D H-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 150; Includes: (1) Screw Set.
SQUARE D
Panelboard Main Breaker Kit: 150 Amps, For Use With Square D H-Frame Panelboards (MPN N150MH). Key specifications — Frame Size: 150A/H; Phase: Three; Compatible Circuit Breaker Series: HRL; For Use With: Square D H-Frame Panelboards; Accessory Type: Panelboard Main Breaker Kit; Amps: 150; Includes: (1) Screw Set.