Built for commercial and industrial distribution, the Eaton HLB3300 is a 300A, 3-pole molded case circuit breaker from the classic Mark 75 family. It provides reliable thermal-magnetic protection for heavy-duty electrical systems. This L-Frame unit serves as an exact physical and electrical match for legacy Westinghouse panelboards. Using this original-spec breaker eliminates the need for the TAD3 spacer kit required when retrofitting with newer Series C KD3300 models. Rated for 65kAIC at 240V.
Mark 75 High Interrupting Capacity, Interchangeable Trip Unit
Product FAQs
7 answers
What types of enclosures are compatible with the HLB3300?
The HLB3300 is an L-Frame circuit breaker designed for use in legacy Westinghouse and Eaton Cutler-Hammer panelboards, switchboards, and motor control centers. It is commonly used as a direct replacement in older distribution systems.
What is the difference between the LB3300 and the HLB3300?
Both are 300A, 3-pole L-Frame circuit breakers, but the HLB3300 is part of the Mark 75 family, which features a higher interrupting capacity. The HLB3300 is rated for 35kAIC at 480V, whereas the standard LB3300 has a lower short-circuit rating.
Are Eaton and Westinghouse HLB3300 breakers the same?
Yes. Eaton acquired the electrical distribution business from Westinghouse. An Eaton HLB3300 is the exact same physical and electrical L-Frame breaker as the original Westinghouse HLB3300.
What wire sizes are accepted by the lugs on this breaker?
The standard lugs for the HLB3300 accept either a single 1 AWG to 600 kcmil wire or dual 1 AWG to 250 kcmil wires. The terminals are compatible with both aluminum and copper conductors.
Can the HLB3300 be used in DC applications?
Yes, this thermal-magnetic breaker is rated for use on DC systems up to 250VDC, providing a direct current interrupting rating of 22kAIC.
How is the trip unit configured on the HLB3300?
This breaker features a thermal-magnetic trip unit with a fixed thermal element for long-time overload protection and an adjustable magnetic element for instantaneous short-circuit protection.
What does the Mark 75 designation mean on this breaker?
The Mark 75 label indicates that the breaker is a high-interrupting capacity model. For the HLB3300, this provides a maximum interrupting rating of 65kAIC at 240VAC and 35kAIC at 480VAC.
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