Square D Breaker Decoder

How It Works

1. Type the catalog number

   Enter the full Square D catalog number exactly as printed on the breaker, for example QO120, QO230, or HOM250. Spaces and internal dashes are ignored and lowercase is accepted; the tool normalizes to uppercase.

2. Read the segment breakdown

   The tool splits the code into colored chips: series prefix (QO/QOB/HOM), the single pole digit, the amp code, any rating suffix (H or VH), and any feature suffix. This shows you exactly how it parsed the string so you can sanity-check the pole-versus-amp split.

3. Check the decoded result

   For a recognized code you get poles, amperage, voltage rating, and the interrupting rating in kA AIR, plus a plain-English summary. A verified-row result (high confidence) means it matched a Schneider/Square D source catalog row; an in-grammar result (medium confidence) means it was decoded from the grammar with the AIC read from the matrix, not an individually enumerated row.

4. Watch for the flag

   If the code is not a real product, an illegal pole count, an out-of-scope PowerPacT/I-Line frame, or a (series, poles, amp) combination not in the cached matrix, the tool refuses to decode it and tells you why instead of inventing a number. Needs-source means the AIC is not asserted, not that it is zero.

5. Verify against the label and digest

   Treat the output as a first pass. Confirm poles, amperage, voltage, and AIC against the physical breaker label and the current Schneider digest before using any value for sizing, replacement, or short-circuit-current-rating decisions.

6. Export or share if needed

   Use the CSV or branded PDF export to drop the decode into a work order or panel-schedule note, or use the share button to copy a URL that reopens the same decoded code.

Built For

• Confirming a replacement breaker on a panel schedule: type QO230 to confirm it is a 2-pole 30 A 120/240 Vac 10 kA device before pulling a spare off the shelf.
• Catching the H-versus-VH trap during a short-circuit-current-rating review: enter QO230VH to see 22 kA AIR instead of assuming the 10 kA standard rating.
• Reading an unfamiliar single-pole code on a service call: QO120 returns 1-pole 20 A 120/240 Vac 10 kA so an apprentice does not misread the amperage off the catalog number.
• Identifying a Homeline breaker in a load center: HOM250 decodes as a 2-pole 50 A 120/240 Vac 10 kA Homeline device, and the tool flags HOM3xx as invalid because Homeline branch breakers are 1-pole and 2-pole only.
• Verifying a high-amp feeder breaker: QO2200 reads as a 2-pole 200 A 120/240 Vac 10 kA breaker, useful when matching a feeder breaker to a panel.
• Screening a code that turns out to be out of scope: paste HDL36100 and the tool recognizes it as a PowerPacT/molded-case frame and refuses to decode it because the AIC is frame-specific.
• Sanity-checking a typo or fictional code: QO999 is flagged invalid because 999 A is not a standard QO rating, so nobody orders a part that does not exist.

Features & Capabilities

AIC read from the matrix, never guessed

The interrupting rating is resolved from Schneider's interrupting-rating matrix on the full (series, poles, amp) token, not inferred from a single letter. A combination that is not in the matrix returns needs-source with no AIC.

Correct pole and amp parsing

The pole count is taken from the single digit immediately after the series letters and the remaining digits are the amp code, so the classic QO230 misreading (2-pole 30 A, not 230 A) does not happen.

Refuses out-of-scope and unsourced codes

PowerPacT and I-Line frame codes are recognized but deliberately not decoded in this version, and unknown or unsourced feature suffixes return needs-source rather than borrowing a base AIC.

Source boundary on every result

Each decode carries a verify-against-the-label note, a source citation, and field notes, and the standard exports are available so the decode can travel with the job.

Assumptions

• The input is a Square D branch-breaker catalog number in the QO, QOB, QOU, QOH, QH, QHB, or HOM families; spaces, lowercase, and internal dashes are normalized away.
• The pole count is the single digit immediately after the series letters and the remaining digits are the amp code (QO230 = 2-pole 30 A).
• The interrupting rating is read from Schneider's published interrupting-rating matrix (QO/QOB catalog 0730CT9801R1/08 Table 1, Homeline USESI 660697 Table 1.36) on the full code.
• Standard QO/QOB/Homeline are 10 kA; VH is 22 kA; QOH is 42 kA; QH/QHB are 65 kA; a lone H on a 2-pole QO is a 240 Vac common-trip device rated 10 kA.
• Voltage is reported as 120/240 Vac for 1-pole and 2-pole QO/QOB/Homeline, and 240 Vac for 3-pole QO and for the 2-pole H common-trip device.
• The AIC classes (10/22/42/65 kA) are treated as stable across the 2008, 2020, and current product-page editions for these families; the exact current digest page and table still need to be pinned.

Limitations

• It does not determine series rating, selective coordination, panel or load-center compatibility, available-fault-current adequacy, or NEC/AHJ acceptability. It is a catalog-number decoder only.
• It does not infer an interrupting rating from a similar series, voltage, suffix, or frame; a (series, poles, amp) combination not in the cached matrix returns needs-source with no AIC.
• PowerPacT and I-Line codes are recognized but deliberately not decoded in this version because their AIC varies by frame, voltage, and interrupting suffix.
• A 2-pole QOH returns needs-source: the pole convention versus the QOH2xx catalog numbers is an unresolved gap, so the 42 kA value is asserted only on the sourced 1-pole row.
• Feature suffixes are gated: GFI, AFI, CAFI, and PL read the feature-specific band, but DF, PDF, HID, SWN, EPD, HM, and any unrecognized suffix return needs-source rather than borrowing the base AIC.
• Only a small set of standard QO and Homeline catalog numbers are individually verified rows; VH, QOH, QH, QOU, and non-launch standard amps decode from the grammar plus the matrix and are not individually enumerated.
• The exact current Schneider digest edition, page, and table number are not yet pinned, so every value must be confirmed against the physical breaker label and the current digest before use.

References

• Square D QO and QOB Miniature Circuit Breakers Catalog 0730CT9801R1/08 (07/2008, Class 730), Table 1: Interrupting Ratings (p5); spine for the QO/QOB AIC matrix.
• Square D Digest catalog page, Standard QO Plug-On Circuit Breakers and Homeline (2020), Table 1.1, AIR-class headers 10k/22k/42k/65k; cross-check confirming VH = 22 kA, QOH = 42 kA, QH = 65 kA.
• Square D Homeline Circuit Breakers brochure (distributor-hosted, USESI 660697, Class 685), Table 1.36: HOM 1-pole and 2-pole amp list with AIR.
• Schneider Electric se.com product pages for QO120, QO230, HOM120, and HOM250 (accessed 2026-06-27), used as per-code validation rows.
• Schneider Electric Digest 178 Section 1 (load centers and branch breakers) and Section 7 (circuit breakers); exact digest edition, page, and table number still to be pinned before launch.

Frequently Asked Questions