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Manufacturer Resources
Product Specs
- Alarm Lockout:
- Ground fault alarm
- Amperage Rating:
- 125A
- Compliances:
- Contact Manufacturer
- Frame Size:
- Frame J-K
- Number Of Poles:
- Three-pole
- Product Height:
- 5.38 IN
- Product Length Depth:
- 8.38 IN
- Product Weight:
- 5.12 LB
- Product Width:
- 3.5 IN
- Series:
- Series C
- Trip Type:
- LSIA
- Department:
- Electrical
- Product Type:
- Trip unit
- Product Details:
- Trip unit
B-LINE KEP3125T57 – Frequently Asked Questions
1) What frame breakers does the Eaton KEP3125T57 trip unit fit?
The KEP3125T57 is a Series C trip unit for Frame J-K molded case breakers. It is a three-pole unit rated 125A, so it belongs in a three-pole J or K frame breaker sized for that rating. It is a replacement/accessory trip unit, not a complete breaker, so the frame already has to be in the door.
2) What protection functions does an LSIA trip unit give me?
LSIA means four elements: long time (L), short time (S), instantaneous (I) and ground fault alarm (A). The alarm function on the KEP3125T57 signals a ground fault rather than tripping on it, so if your spec calls for ground fault trip instead of alarm you need a different suffix.
3) Will this trip unit trip the breaker on a ground fault?
No. The KEP3125T57 is configured for ground fault alarm only, meaning it annunciates the ground fault condition without tripping on it. Where the drawing calls for ground fault protection of equipment that actually opens the breaker, this is the wrong unit.
4) Is the KEP3125T57 a complete circuit breaker or just the trip unit?
Just the trip unit. It is a breaker accessory, so you get the electronic trip module only, not the frame, poles, lugs or the breaker body. Ordering this to replace a whole breaker leaves you short.
5) Can I use this 125A trip unit on a single-phase two-pole breaker?
No. The KEP3125T57 is built as a three-pole unit, so it mates to three-pole J/K frame breakers only. A two-pole application needs a two-pole trip unit of the same frame family.
6) What part number should I give my distributor for this Eaton trip unit?
Order it as Eaton KEP3125T57, Series C, 125A three-pole LSIA trip unit for J-K frame. That single manufacturer number covers it, there are no finish or size options to specify.
7) What are the dimensions and weight of the KEP3125T57 trip unit?
It measures 8.38 in length/depth, 5.38 in height and 3.5 in width, and weighs 5.12 lb. Useful if you are checking gutter space or panel door clearance before pulling the old unit.
How fast can I get the B-LINE KEP3125T57 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the
continental
U.S.
Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the B-LINE KEP3125T57 come with a warranty?
Absolutely. The B-LINE KEP3125T57 is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the B-LINE KEP3125T57?
You can call, text, or email our expert support team for fast answers. We’re here to help with
product
selection,
installation tips, and troubleshooting. Contact Us
Why buy the B-LINE KEP3125T57 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support,
and
rewards on
every order.
Our team is always ready to help you choose the right product for your project.