Engineered for legacy Square D NQOB panelboards, the Q1B250VH is a 2-pole, 50A bolt-on molded case circuit breaker. It provides reliable thermal-magnetic protection for commercial applications. This unit mounts securely into older NQOB enclosures. It is officially replaced by the QOB250VH, which requires an SK5668 mounting kit for backward compatibility. Rated at 22kAIC at 120/240VAC, it includes a Visi-Trip indicator for quick fault identification and box lugs for secure connections.
HACR Rated, Visual Trip Indicator, High Interrupting Capacity
Product FAQs
7 answers
What panelboards are compatible with the Square D Q1B250VH circuit breaker?
The Q1B250VH is a bolt-on branch breaker designed specifically for use in older Square D NQO and NQOB panelboards.
Can I replace a legacy Q1B breaker with a newer QOB model in my NQOB panelboard?
Yes, but replacing a Q1B breaker with a modern QOB circuit breaker requires the Square D SK5668 horizontal bus bar mounting kit to adapt the connection. Installing an exact Q1B replacement like the Q1B250VH avoids the need for this adapter kit.
Can the Q1B250VH be installed in modern Square D NQ panelboards?
No. While NQ panelboards replaced the older NQOB line, they are designed to accept QO and QOB branch breakers. The Q1B250VH is specifically intended for legacy NQO and NQOB panelboards.
What does the VH in the Q1B250VH catalog number indicate?
The VH designates this as a high-interrupting breaker. It features an interrupting rating of 22kAIC at 240V, which is higher than standard Q1B breakers, providing robust protection against severe short circuits.
What wire gauge is accepted by the terminals on the Q1B250VH?
The box lugs on this 50A breaker accept wiring ranging from 8 AWG to 2 AWG. Ensure your conductors are sized appropriately for the 50A load and local electrical codes.
How does the Q1B250VH install into the panelboard?
This is a bolt-on circuit breaker. It secures directly to the panelboard bus using screws, ensuring a tight, reliable connection that resists vibration in commercial and industrial environments.
What type of trip unit does the Q1B250VH use?
It uses a fixed thermal-magnetic trip unit with long-time and instantaneous (LI) trip functions. The thermal element responds to sustained overloads, while the magnetic element trips immediately during short circuits.
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