800.497.6255
  • 800.497.6255
  • Hours

    Hours of Operation

    Mon - Fri:
    8AM - 8PM EST
    5AM - 5PM PST
    We offer after hours sales & support for outages and electrical emergencies. Call us 24/7
    Contact Us

ABB Q-Line Breaker Replacement

Upgrading to FORMULA A2 and Tmax XT Breakers

ABB Q-Line Breaker Replacement: a reliable workhorse in for decades.

Need Electrical Products?

Get Quote
Table Of Contents
  1. Upgrading to FORMULA A2 and Tmax XT Breakers
  2. Why Q-Line Is Being Replaced
  3. FORMULA A2: ABB Q-Line Breaker Replacement
  4. When Tmax XT Is the Better Choice
  5. How You Choose the Right ABB Q-Line Replacement
  6. Planning to Upgrade or Replace Q-Line Breakers
  7. Cross-Referencing Q-Line Circuit Breakers

Why Q-Line Is Being Replaced

If you’ve worked in commercial or light-industrial electrical for a while, you have likely installed or serviced ABB Q-Line molded case circuit breakers. They’ve been a reliable workhorse in for decades.
However, Q-Line breakers are being phased out for improved systems that have more availability, broader ratings, and advanced functions.

The good news? ABB made ABB Q-Line Breaker Replacement easier to transition by designating FORMULA A2 and Tmax XT molded case circuit breakers as today’s recommended Q-Line breaker replacements.

Q-Line breakers were designed for a different era of electrical systems. Today’s facilities demand:
– Higher short-circuit ratings
– More standardized frames and accessories
– Faster installation and easier configuration
– Optional electronic trip units and diagnostics.

ABB now offers a streamlined molded case portfolio, and their circuit breaker transition guide specifies FORMULA A2 as the replacement for Q-Line TQD and THQD breakers, with Tmax XT covering applications requiring better performance or enhanced features.

FORMULA A2: ABB Q-Line Breaker Replacement

For most Q-Line replacement jobs, FORMULA A2 thermal-magnetic molded case circuit breakers are your first stop.
FORMULA A2 breakers are designed to replace:

TQD (10 kA @ 240 VAC)
THQD (22 kA @ 240 VAC)
in both 2-pole and 3-pole configurations.

What Makes FORMULA A2 a Good Fit
– Thermal-magnetic trip unit (simple and familiar)
– UL and IEC rated
– Frame size up to 250 A
– Wide range of current ratings from 15 A through 250 A
– Available in 2-pole and 3-pole versions

If you’re replacing a Q-Line breaker in a panelboard, lighting panel, or small distribution application, FORMULA A2 is usually a straightforward option. Think of FORMULA A2 as the modern version of what you’ve been installing for years — same basic operating principle, with updated manufacturing and current stock available.

When Tmax XT Is the Better Choice

Some replacements go beyond basic thermal-magnetic needs. That’s where Tmax XT molded case circuit breakers come in.

ABB’s Tmax XT platform includes seven frame sizes (XT1 through XT7) covering 125 A up to 1200 A, with interrupt ratings up to 200 kA depending on frame and voltage.

Advantages of Tmax XT
– Multiple frame sizes to fine-tune
– Thermal-magnetic and trip unit options
– Field-upgradeable electronic trip units
– Plug-and-play communication on advanced models
– Can be installed in up to 40% less time

You’ll usually recommend Tmax XT when:

  • Higher interrupt ratings are required
  • Electronic trip functions (LSI / LSIG) are needed
  • Metering, monitoring, or communication is desired
  • Future expandability matters

Simply put, FORMULA A2 handles “like-for-like” Q-Line replacement. Tmax XT handles everything else.

ABB Q-Line replacement

Popular Q-Line Breaker Models

Part Number Short Description Replacement (FORMULA A2 / Tmax XT)
THQL1120 20A, 1-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 20A / Tmax XT1
THQL1130 30A, 1-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 30A / Tmax XT1
THQL2140 40A, 2-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 40A / Tmax XT1-XT2
THQL2150 50A, 2-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 50A / Tmax XT2
THQL2160 60A, 2-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 60A / Tmax XT2
THQL21100 100A, 2-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 100A / Tmax XT2-XT3
THQL21125 125A, 2-Pole Q-Line Thermal-Magnetic Breaker FORMULA A2 125A / Tmax XT3
THQB1120 20A, 1-Pole Bolt-On Q-Line Breaker FORMULA A2 20A / Tmax XT1

How You Choose the Right ABB Q-Line Replacement

ABB’s transition guide outlines a simple migration approach that works just as well in the field as it does at your electrical distributor’s counter. Start with five basics:

  1. What voltage do you need?
  2. What amperage do you need?
  3. What interrupting rating is required?
  4. How many poles?
  5. 80% or 100% rated?

✅ Then confirm electrical features:

  • Thermal-magnetic or electronic trip?
  • Need L, S, I, or G protection?
  • Any metering or communication requirements?

If the original installation is outdoors, in a wash-down area, or exposed to weather, determining enclosure type is just as important as selecting the breaker.

Planning to Upgrade or Replace Q-Line Breakers

Waiting until a breaker fails can turn a simple replacement into an emergency. Legacy part numbers may be unavailable, lead times grow, and temporary fixes cost more than planned upgrades. Standardize on FORMULA A2 and Tmax XT:

  • You simplify stocking
  • Reduce cross-reference errors
  • Shorten downtime
  • Future-proof customer installations

For electrical contractors, this means fewer surprises. For facility owners, it means better long-term reliability.

Cross-Referencing Q-Line Circuit Breakers

If you’re replacing ABB Q-Line breakers today:

  • Start with FORMULA A2 for direct, thermal-magnetic replacements
  • Step up to Tmax XT when ratings, features, or future expansion require it

Both platforms are UL listed, stock available, supported by ABB as current molded case breaker solutions.

Need help cross-referencing a specific Q-Line part number or confirming the best FORMULA A2 or Tmax XT option?, Call Our team at 800.497.6255, we can walk through it with you and make sure you get a compliant, drop-in solution.