ABB THQB Bolt-On Circuit Break...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$334.64
ABB THQB Bolt-On Circuit Breaker, 120/240V

ABB THQB Bolt-On Circuit Breaker, 120/240V

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Model: THQB1120ST1

In Stock (leaves warehouse same day if ordered before 3pm ET)

$334.64
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ABB THQB Bolt-On Circuit Breaker, 20A 1-Pole 120/240V HID

The ABB THQB is a bolt-on Q Line circuit breaker built for residential and commercial panelboards and lighting panels. This compact, one-inch-wide-per-pole thermal-magnetic device is rated 20A, 1-pole, 120/240V, with a 10kA interrupt rating, and is configured for HID (high intensity discharge) lighting applications. Like all Q Line breakers, the THQB bolts directly to the bus connections of a load center or lighting panel and combines a Quick-make / Quick-break mechanism with a common trip bar and easy-to-spot trip indication for dependable, code-compliant circuit protection. The THQB is part of the broader Q Line family, which is available in 1, 2, and 3-pole versions and can be ordered with auxiliary contact or shunt trip accessories, giving electricians flexibility when specifying panel protection for HID lighting circuits.

Key Features

  • Amperage Rating: 20A rating configured for HID (high intensity discharge) lighting loads.
  • Poles: 1-pole configuration with a common trip bar for reliable circuit isolation.
  • Voltage Rating: Rated for 120/240V residential and commercial distribution systems.
  • Interrupt Rating: 10kA interrupt capacity for dependable fault protection.
  • Bolt-On Mounting: Bolts directly to the bus connections of Q Line load centers and lighting panels.
  • Quick-Make / Quick-Break Mechanism: Fast-acting operation for improved safety during switching and fault clearing.
  • Trip Indication: Easy-to-spot trip indicator lets electricians quickly identify a tripped breaker.
  • Compact Design: One-inch wide per pole for space-efficient panel layouts.
  • Family Flexibility: Part of the Q Line series, available in 1, 2, and 3-pole versions with optional auxiliary contact and shunt trip accessories.

Technical Specifications

  • Country of Origin: UKN
  • Packaging: 1 EA

Typical Applications

  • Residential and Commercial Panelboards and Load Centers
  • Lighting Panel Circuit Protection
  • HID (High Intensity Discharge) Lighting Circuits
  • Bolt-On Bus Connection Retrofits and Replacements
  • Renovation and New Construction Electrical Distribution

Why ABB?

The ABB THQB Q Line circuit breaker delivers the bolt-on reliability, Quick-make / Quick-break switching, and clear trip indication that electrical professionals depend on for safe, code-compliant panel protection. Its compact thermal-magnetic design and 10kA interrupt rating make it a dependable choice for 120/240V residential and commercial circuits, including dedicated HID lighting loads. For contractors and facility teams standardizing on Q Line panels, the THQB offers a straightforward bolt-on replacement or new-install option that matches the fit, function, and safety features of the wider ABB Q Line breaker lineup.

Manufacturer Resources

Spec Sheet

Product Specs

Product Group:
Circuit Protection
Product Type:
Circuit Breaker
Voltage Rating:
120/240V
Configuration:
1-Pole
Department:
Electrical
Product Subgroup:
Circuit Breakers

ABB THQB1120ST1 – Frequently Asked Questions

1) Will an ABB THQB breaker fit a plug-on load center, or does the panel have to be bolt-on?
The THQB is a bolt-on Q Line breaker. It fastens directly to the bus connections of a Q Line load center or lighting panel, so the panel interior has to be drilled and tapped for bolt-on mounting. If your panel takes plug-on breakers that clip onto the bus stab, a THQB will not seat in it. Check the panel label for bolt-on Q Line acceptance before ordering.
2) What amperages and pole counts can I get in the ABB THQB line?
1-pole THQB runs 15A, 20A, 25A, 30A and 60A. The 2-pole covers 15, 20, 25, 30, 40, 45, 50, 60, 70, 80, 90 and 100A. The 3-pole covers 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90 and 100A. Part numbers follow the pattern: THQB1120 is 20A 1-pole, THQB2150 is 50A 2-pole, THQB32060 is 60A 3-pole.
3) Is there an ABB THQB breaker made specifically for HID lighting circuits?
Yes, THQB1120HID is the 20A 1-pole version configured for high intensity discharge lighting loads. HID ballasts draw a long inrush at startup, and the HID-rated unit is the one to specify for metal halide or high pressure sodium lighting panels. A standard THQB1120 is the same amperage but is not the HID configuration.
4) Can I get a THQB with shunt trip for a fire alarm or elevator disconnect?
Shunt trip is available as a factory configuration, not something you add in the field on these. THQB1120ST1 is the 20A 1-pole shunt trip and THQB32030ST1 is the 30A 3-pole shunt trip. The Q Line family also supports auxiliary contact accessories. If your elevator or kitchen hood shutdown scheme needs remote tripping, order the ST version rather than a standard breaker.
5) Does ABB make an arc fault version of the THQB for bedroom and living area circuits?
THQB1120AF2 is the 20A 1-pole arc fault version. That is the one to use where the NEC requires AFCI protection on 120V branch circuits. The plain THQB1120 is thermal-magnetic only with no arc fault sensing.
6) Can a Square D Multi9 C60 breaker be used in place of an ABB THQB in a Q Line load center?
No. The THQB is a bolt-on breaker that fastens directly to the bus connections of a Q Line load center or lighting panel, one inch wide per pole. The Square D Multi9 C60 is a miniature circuit breaker built for DIN rail mounting, so it has no bus stab or bolt-on interface and needs a DIN rail enclosure instead of a panelboard bus. Use the C60 family where the design calls for DIN rail control or distribution gear, and the THQB where a Q Line panel bus is being fed.
7) What should I use instead of a THQB if the panel is an I-Line panelboard?
The ABB THQB is built for Q Line load centers and lighting panels and bolts to that bus, so it will not land in an I-Line panelboard. For I-Line gear the Square D PowerPacT Q I-Line circuit breaker is the family designed for that bus connection. Keep the THQB for Q Line 120/240V residential and commercial distribution.
8) How many breaker spaces does a 2-pole or 3-pole THQB take up in the panel?
Q Line THQB breakers are one inch wide per pole. A 1-pole takes one space, a 2-pole takes two, and a 3-pole takes three adjacent spaces. Multi-pole versions use a common trip bar so all poles clear together on a fault.
9) Can I use a THQB on a 208Y/120 three phase panel?
The THQB is rated 120/240V. A 3-pole THQB such as the THQB32060 is built for three phase distribution at that voltage class, and single pole units serve 120V line-to-neutral circuits. For 480V or 277/480V systems this is the wrong breaker family entirely.
10) What else could I use if my panel is DIN rail rather than a Q Line load center?
The THQB will not work on DIN rail, it is a bolt-on bus-mounted breaker. For DIN rail applications look at the Square D C60 UL489 miniature circuit breaker, which is built for DIN rail mounting, or the Square D Multi9 C60 1-pole C-curve MCB for 120V AC control and lighting circuits.
11) I need a molded case breaker for a feeder, not a branch circuit. What should I look at instead of a THQB?
THQB tops out at 100A in 2 and 3-pole and is a panelboard branch and small feeder device. For larger molded case feeder duty, the Square D PowerPacT B thermal magnetic breaker is the comparable option, and the PowerPacT Q I-Line breaker is the choice where the panel is an I-Line bus rather than a Q Line load center.
12) How does the ABB THQB differ from a Square D PowerPacT B breaker?
Both are thermal-magnetic devices. The THQB is a plug-and-bolt Q Line branch breaker, one inch wide per pole, rated 120/240V with a 10kA interrupt rating and available in 1, 2, and 3-pole versions from 15A through 100A. The Square D PowerPacT B is a molded case thermal magnetic breaker in its own frame, typically applied as a main or feeder device rather than a Q Line panel branch breaker. Choose by what the panel bus accepts and whether the circuit is a branch or a feeder.
13) For a 3-pole 480V circuit, is the THQB the right breaker?
No. The ABB THQB is rated 120/240V, including its 3-pole versions from 15A to 100A, so it does not cover higher-voltage three-phase distribution. For that duty look to a molded case family such as the Square D PowerPacT B thermal magnetic breaker or the PowerPacT Q I-Line breaker, chosen to match the panel and system voltage. Keep the THQB on 120/240V Q Line panels.
14) How do I tell which breaker tripped in a THQB panel?
Q Line THQB breakers have a trip indicator, so a tripped pole sits visibly between on and off rather than looking like someone switched it off. Combined with the Quick-make / Quick-break mechanism, that lets a facility tech identify and reset the faulted circuit without meter work.
15) Are THQB breakers sold individually or in multi-packs?
THQB breakers are packaged one each, so quantity ordered equals breakers received. Useful when you are filling a panel schedule and need an exact count of 15A and 20A single poles.
How fast can I get the ABB THQB1120ST1 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 ABB THQB1120ST1 come with a warranty?
Absolutely. The ABB THQB1120ST1 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 ABB THQB1120ST1?
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
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