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Square D EJB34090 Miniature Circuit Breaker

  • 90A
  • 3 Pole
  • Bolt-On
Square D EJB34090
Miniature Circuit Breaker
Brand Square D
SKU EJB34090
Select Item Condition
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  • 90A
  • 3 Pole
  • Bolt-On

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Square D EJB34090 - 90A 3 Pole Miniature Circuit Breaker

Square D EJB34090 - 90A 3 Pole Miniature Circuit Breaker

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$595.00 No Stock

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Description

Providing reliable overcurrent defense, the Square D EJB34090 is a 90A, 3-pole miniature circuit breaker. It is engineered for commercial facilities utilizing 480Y/277VAC networks. This E-Frame breaker features a bolt-on mounting configuration tailored exclusively for Square D NF panelboards. It comes equipped with load-side lugs that accept 14-2/0 AWG copper or aluminum wiring. The unit boasts a 100 kAIC rating at 240V, is HACR rated, and includes a Visi-Trip indicator for fast troubleshooting.

Specifications

Key specifications
Brand Square D
Part Number EJB34090-R
Series EJB
Amperage 90A
Poles 3
Mounting Style Bolt-On
Voltage 120VAC, 240VAC, 277VAC, 480Y/277VAC
Phase 3
AIC Rating 100kA @ 120VAC, 100kA @ 240VAC, 65kA @ 277VAC, 65kA @ 480Y/277VAC
Fit and installation
Frame Type EJB
Terminal Type Lugs
For Use With Square D NF Panelboards
Wire Gauge 14-2/0 AWG (Cu), 12-2/0 AWG (Al)
Max Wire 2/0 AWG
Min Wire 14 AWG (Cu), 12 AWG (Al)
Protection and operation
Trip Technology Thermal Magnetic
Trip Function Code LI
Trip Function Long-Time, Instantaneous
Trip Adjustability Fixed
Standards and features
Available Options Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment
Accessories Load Side Lugs Included
Standards CSA C22.2 No. 5, HACR, NEMA AB 1, NFPA 70, UL 489
Approval CSA, cULus, NOM, UL
Temp Rating 40C
Construction Features HACR Rated, Visual Trip Indicator

Product FAQs

7 answers
Can the EJB34090 be used on a 480V ungrounded delta system?

No. This breaker is rated for 480Y/277VAC, meaning it must be installed on a solidly grounded wye system where the line-to-ground voltage does not exceed 277V. It is not rated for use on 480V delta systems.

What is the difference between Square D EDB, EGB, and EJB circuit breakers?

These breakers share the same physical footprint and mount in NF panelboards, but they have different interrupting ratings. At 480Y/277VAC, EDB breakers provide up to 18kAIC, EGB breakers provide 35kAIC, and EJB breakers provide 65kAIC.

Can the EJB34090 be backfed?

Yes. Standard Square D E-frame breakers, including the EJB34090, do not have Line and Load markings and can be safely reverse-fed. Note that this does not apply to EPD (Equipment Protection Device) variants, which are distinctly marked and cannot be backfed.

Is the EJB34090 HACR rated?

Yes. Square D E-frame molded case circuit breakers carry an HACR rating, making them suitable for group motor applications in heating, air conditioning, and refrigeration equipment.

Can I install the EJB34090 in a Square D NQ or I-Line panelboard?

No. The EJB34090 is an E-frame breaker designed exclusively for Square D NF panelboards. It uses a specific bolt-on configuration that will not fit in NQ panelboards (which accept QO or QOB breakers) or I-Line distribution panels.

What is the recommended tightening torque for the load lugs on this breaker?

Torque specifications vary by wire size. For 14 to 10 AWG wire, the standard torque is 34.5 lb-in. For 8 to 2/0 AWG wire, the standard torque is 49.6 lb-in. Always verify against the manufacturer label printed on the side of the breaker.

Does this breaker mount onto a standard DIN rail?

No. While often classified as a miniature circuit breaker, the EJB34090 does not use a DIN rail mounting system. It requires a bolt-on connection directly to the busbar of a compatible NF panelboard.

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Reviews

4.9
Rated 4.9 out of 5 stars
Based on 12 reviews
Total 5 star reviews: 11
Total 4 star reviews: 1
Total 3 star reviews: 0
Total 2 star reviews: 0
Total 1 star reviews: 0
Rating
Ratings
12 reviews
  • EO
    Eric O.
    Verified Buyer
    Reviewing
    Square D EJB14040 - 40A 1 Pole Miniature Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    8/5/26
    Breaker Replacement

    I needed a replacement breaker fast, and SuperBreakers pulled it off for me without any issues.

  • BB
    Brad B.
    Verified Buyer
    Reviewing
    Square D EJB34125 - 125A 3 Pole Miniature Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    6/27/26
    Breaker Order

    Thanks! Ordering was easy and the part was delivered quickly and accurately. All I can ask for!

  • RR
    Rodolfo R.
    Verified Buyer
    Reviewing
    Square D EJB34015 - 15A 3 Pole Miniature Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    1/14/26
    Satisfied Customer

    The breaker was received in good condition and it works good. Lead time was not long it all.

    Very happy with SuperBreakers Rep. Good customer service.

  • RN
    Randy N.
    Verified Buyer
    Reviewing
    Square D EJB34070 - 70A 3 Pole Miniature Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    11/14/25
    Breaker value

    saved a lot compared to what the electrician wanted to charge us, at least half the price.

  • TW
    Timothy W.
    Verified Buyer
    Reviewing
    Square D EJB34020 - 20A 3 Pole Miniature Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    10/15/25
    Circuit Breaker

    Product arrived in a timely matter and met expectations to repair the problem that we had.