Miniature Circuit Breaker Patents: Top Companies & Trends 2026
- Five filers hold 84.9% of the field. 185 of 218 records in scope sit with the top five assignees, leaving a thin long tail of single-digit and single-filing entrants.
- Filing activity peaked in 2021 at 14 records and has since fallen to zero by 2024. Publication lag means the most recent years are still filling in, but the drop from the 2021 peak is steep enough to flag on its own.
- H01H switch and relay claims cover 78.9% of records. Protective circuit arrangements (H02H) and measurement claims (G01R) trail well behind, at 33.5% and 11.9% of the 218 records respectively.
Filing growth compares 2021 (14 records) with 2024 (0) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 218 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape tracks 218 published records at the intersection of miniature circuit breaker hardware and its trip logic: bimetal calibration, magnetic armature response, tripping curve shaping, selectivity coordination, endurance cycling and terminal heating. The search deliberately pairs mechanical breaker terms with the calibration and coordination language that separates a generic breaker filing from one that claims how the trip behaviour itself is tuned and verified. Patent families, not raw document counts, are the fairer unit here because they neutralise repeat continuation filings from the largest assignees.
The dataset spans 2015 through the 2026-07-31 cut-off, with receiving-office activity concentrated in the United States, Canada and Europe and a smaller but present India and PCT presence. Coverage this way surfaces both the incumbent claim thickets around thermal-magnetic trip mechanisms and the comparatively open ground around digital sensing and grid-integration variants.
Filing trend and technology composition
The trend line and class breakdown below are drawn from the same 218-record scope used throughout this page; a record can carry more than one IPC class, so class shares add up to more than 100%.
Filing trend: a 2021 peak followed by a steep falloff
Filings rose to a peak of 14 records in 2021, then fell to zero by 2024 — a -100% move over that three-year span. 2025 and 2026 are still incomplete because publication typically lags filing by around 18 months, so treat the most recent bars as a floor, not a verdict on current activity.
H01H dominates; protective circuitry and measurement trail
H01H (switches and relays) appears on 78.9% of the 218 records, confirming this is still primarily a mechanical-switching claim space. H02H protective circuit arrangements sit at 33.5% and G01R measurement and sensing at 11.9%, with digital processing (G06F, 2.3%) and grid/power-supply integration (H02J, 0.9%) barely represented.
Shares are the percentage of the 218 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Miniature Circuit Breaker Design with Eureka
This page is one run against one query. Ask Eureka your own question about miniature circuit breaker design and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited prior art in this space
US5302787A — Automatic miniature circuit breaker with Z-axis assemblable contact assembly
An improved miniature circuit breaker is provided which is adapted to improved automatic assembly of all components thereof. Key components of the breaker are individually and collectively designed to be susceptible to total Z-axis assembly. In particular, the circuit breaker operating mechanism which operates the contacts thereof to make or break the electric circuit is formed of elements designed to interact in a Z-axis assemblable fashion. The movable contact is defined on a contact carrier or blade assembly which is adapted for Z-axis assembly and also provides increased arc erosion resistance and improved opening of the breaker contacts.Filed by Square D Company; granted 1994-04-12. Its Z-axis assembly claims still shape how contact-carrier geometry is drafted around today.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5691869A | Low cost apparatus for detecting arcing faults and circuit breaker incorporating same | 311 |
| 2 | US5519561A | Circuit breaker using bimetal of thermal-magnetic trip to sense current | 226 |
| 3 | US5805397A | Arcing fault detector with multiple channel sensing and circuit breaker incorporating same | 171 |
| 4 | US5815352A | Arc fault detector with limiting of sensed signal to shape response characteristic and circuit breaker incopr… | 121 |
| 5 | US5483211A | Two-pole compartmentalized ground fault miniature circuit breaker with a single central electronics compartme… | 95 |
| 6 | US20050103613A1 | Monitor providing cause of trip indication and circuit breaker incorporatiing the same | 89 |
| 7 | US5946179A | Electronically controlled circuit breaker with integrated latch tripping | 85 |
| 8 | US5302787A | Automatic miniature circuit breaker with Z-axis assemblable contact assembly | 60 |
| 9 | US5245302A | Automatic miniature circuit breaker with Z-axis assemblable trip mechanism | 59 |
| 10 | US5453723A | Two-pole compartmentalized ground fault miniature circuit breaker with increased current rating | 52 |
Citation counts inside a searched corpus favour older filings that have had more time to accumulate references; treat them as a signal of influence on later drafting, not of current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for filing strategy
Three patterns in this dataset matter more than the raw counts: where claim density sits, how concentrated ownership is, and how citation influence is distributed across decades of filing.
Mechanical trip mechanisms are the occupied ground
Nearly four in five records in scope touch H01H switch and relay claims. That density means core contact-carrier, armature and bimetal-strip geometry is well covered by prior art — new filings here need a genuinely distinct mechanical arrangement, not a variant on assembly sequence.
A handful of incumbents set the boundaries
The top five assignees combine for 185 of 218 records in scope, with the leader alone accounting for 72. That leaves a long tail of entities filing once or twice — a structure typical of a mature mechanical category where a few large portfolios anchor the claim space.
Arc-fault detection prior art still anchors drafting
The most-cited records in this set are arc-fault and bimetal thermal-magnetic sensing patents from the 1990s, some cited over 300 times. Their continued pull on citation graphs signals that examiners and drafters still measure new sensing claims against that older baseline, even as filing volume has moved on.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to miniature circuit breaker design, with the prior art for and against each one.
Who holds the ground, and where it thins out
Ranking is by patent family count across the 25 companies this dataset's assignee ranking returns — not a top-50 or top-100 list, just the complete ranked set for this search.
One filer anchors the field
The leading assignee's count alone approaches a third of all 218 records in scope, consistent with a category where a small number of legacy switchgear manufacturers built out broad continuation families over decades.
Concentration falls away fast after the top five
By the fifth position, counts have dropped to single digits, and by the tenth position to 3 records. The top ten combined still account for 94.0% of all 218 records, meaning everything past that line is thin, single- or double-filing activity.
Collaboration is limited and inventor-driven
Only seven co-assignee pairs appear in this dataset, and the strongest links are between individual named inventors rather than corporate joint ventures — collaboration here looks more like internal engineering teams than cross-company alliances.
| Assignee | Recent year | YoY |
|---|---|---|
| Eaton Corporation | 0 | — |
| Square D Company | 0 | — |
| Schneider Electric USA, Inc. | 0 | — |
| Energy Distribution Systems (Holdings) Ltd. | 0 | — |
| Siemens Industry, Inc. | 0 | — |
| Felten & Guilleaume Austria AG | 0 | — |
| Larsen & Toubro Ltd. | 0 | — |
| MRENNA STEPHEN ALBERT | 0 | — |
Where to take this analysis
The trend and ownership patterns above point to a category where the mechanical core is settled but the sensing and coordination layer is still open for distinct claims.
Map claim boundaries around the top assignees
Before drafting in H01H trip-mechanism space, pull the specific claim language from the leading assignees' families to see exactly how narrow or broad their contact-carrier and bimetal claims run.
Explore assignee claim scope in EurekaStress-test a digital calibration angle
With G06F and H02J barely represented, a claim combining tripping-curve calibration with grid telemetry has less prior art to design around than a purely mechanical filing.
Run a white space search in EurekaCommon questions about miniature circuit breaker patents
This dataset's assignee ranking is dominated by legacy low-voltage switchgear manufacturers, with the top five combining for 84.9% of all 218 records in scope. The leading assignee alone holds 72 records, and concentration falls steeply after the top five, down to single-digit counts by the tenth position. This is a mature, consolidated filing landscape rather than one with many active new entrants.
Filings peaked at 14 records in 2021 and fell to zero by 2024, a -100% change over that span. However, publication typically lags actual filing by around 18 months, so 2025 and 2026 figures in any dataset are structurally incomplete and should not be read as proof that inventive activity has stopped. The safest reading is that the visible peak has passed and the years since need more time to fill in before drawing conclusions.
H01H (switches and relays) appears on 78.9% of the 218 records in scope, making core mechanical switching and trip-contact design the most heavily claimed territory. H02H protective circuit arrangements follow at 33.5%, and G01R electric and magnetic measurement claims appear on 11.9% of records. Areas like digital processing and grid/power-supply integration are present but thin, each under 4% of records.
The thinnest classes in this dataset are digital data processing (G06F, 2.3% of records), power supply and grid systems (H02J, 0.9%), and magnets/inductors/transformers (H01F, 0.9%). Combining tripping-curve calibration logic with digital telemetry or grid-integration features sits well outside the dense H01H/H02H mechanical core and carries comparatively little prior art in this search. That does not guarantee freedom to operate, but it does mean less claim density to search around.
US5302787A, assigned to Square D Company, claims a Z-axis assemblable contact-carrier and operating-mechanism arrangement for automatic miniature circuit breaker assembly. It is one of the representative records in this landscape because its contact-carrier and arc-erosion-resistance claims still influence how mechanical assembly and blade-contact geometry gets drafted in later filings. Anyone patenting a new contact-assembly method should check its claim scope directly rather than assume it has lapsed out of relevance.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.