Cable Ampacity Patents: Who Leads, Where the Gaps Are 2026
- 60.0% concentration. The top 5 of 44 ranked assignees hold 72 of 120 records in scope — filing here is already concentrated at the top, not wide open.
- Flat, not falling, momentum. Filings held at 2 in both 2021 and 2024 (0% change) — read any dip in 2025-2026 as publication lag, not a slowdown.
- Distributed temperature sensing is the cited core. The two most-cited DTS-for-cable records anchor a body of work that newer entrants still have to design around.
Filing growth compares 2021 (2 records) with 2024 (2) — 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 120 records in scope (CR5), not by the ranked leaders only.
What this dataset covers
This landscape draws on 120 published records filed between 2015 and mid-2026 that combine cable ampacity or current-carrying-capacity claims with a thermal-management mechanism — soil thermal resistivity, backfill material, distributed temperature sensing, dynamic rating, grouping factor or hotspot identification. The scope is narrow by design: it isolates the intersection of electrical rating and thermal physics, not cable manufacturing or insulation chemistry in general.
Records cluster in H01B (cables, conductors and insulators) and G01R (electric and magnetic measurement), with a meaningful secondary presence in G01K (temperature measurement) and H02J (power supply and grid systems). That spread signals a field where the invention is as often the sensing or measurement method as it is the cable construction itself.
Filing trend and technology composition
Two views of the same 120-record dataset: how filing activity moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017-2026
Filings peaked at 6 in 2018 and have since run at a low, flat rate — 2 filings in both 2021 and 2024, a 0% change across that span. 2025 and 2026 show fewer published records, but publication lags filing by roughly 18 months, so those final years are still filling in rather than signalling genuine decline.
IPC subclass composition
H01B accounts for 27.5% of the 120 records and G01R for 20.8%, confirming that cable construction and electrical/magnetic measurement are the two dominant claim bodies. G01K (temperature measurement, 14.2%) and H02J (grid systems, 13.3%) are the next tier; G03F, H01R, H05K and G02B each sit near or above 8-11%, reflecting how often ampacity claims are bundled with connector, circuit-board or optical-sensing elements rather than filed as standalone cable claims.
Shares are the percentage of the 120 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Cable Ampacity and Thermal Design with Eureka
This page is one run against one query. Ask Eureka your own question about cable ampacity and thermal design and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing
Dynamic wide-area earth thermal properties and earth ambient temperature determination system (US9638586B2)
Techniques are described for generating earth sub-surface thermal characteristics over an area by collecting real-time weather data and earth data for multiple locations associated with an underground electrical cable, then calculating earth thermal properties at those locations through an iterative process. The calculated properties at two or more locations are interpolated to determine properties at another location, producing a wide-area thermal property map used to inform cable rating decisions.Filed by Underground Systems, Inc., published 2017-05-02.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20110282508A1 | Generalized grid security framework | 486 |
| 2 | US8924033B2 | Generalized grid security framework | 198 |
| 3 | US6180226B1 | Method of forming a monolayer of particles, and products formed thereby | 127 |
| 4 | US20110218790A1 | System and method for determining characteristics of power cables using distributed temperature sensing syste… | 87 |
| 5 | WO2010053542A2 | System and method for determining characteristics of power cables using distributed temperature sensing syste… | 82 |
| 6 | US20120024565A1 | Submarine electric power transmission cable armour transition | 69 |
| 7 | US6402876B1 | Method of forming a monolayer of particles, and products formed thereby | 65 |
| 8 | US4361661A | Thermal backfill composition method | 62 |
| 9 | US5916641A | Method of forming a monolayer of particles | 59 |
| 10 | US6167525A | Method and system for analysis of electric power transmission link status | 58 |
Citation counts favour older records in any searched corpus — treat them as a signal of influence within this field, not as a ranking of current importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns worth acting on before drafting new claims in this space.
The top of the field is already crowded
Five assignees out of 44 ranked hold 72 of the 120 records in scope. A new entrant filing broad ampacity-plus-thermal-sensing claims is filing directly into occupied space; differentiation needs to sit in a specific measurement method or deployment context, not the general concept.
Flat filing rate, not a dying field
Filings held steady at 2 in both 2021 and 2024. Combined with the 2025-2026 publication lag, this reads as a mature but still-active niche rather than one in decline — worth monitoring rather than writing off.
Cable construction claims still dominate
H01B and G01R together cover the largest share of records, but G01K, H02J, G03F, H01R, H05K and G02B all appear at double-digit or near-double-digit shares. Claims routinely bundle a cable or measurement element with a connector, circuit or optical-sensing component — a sign that standalone thermal-rating claims are getting harder to write novel.
Distributed temperature sensing anchors the prior art
The most-cited records in scope center on determining cable characteristics via distributed temperature sensing. Any new DTS-for-cable filing should expect examiners to cite this cluster directly.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to cable ampacity and thermal design, with the prior art for and against each one.
Who is filing, and where the momentum sits
44 assignees are ranked in this dataset. Filing is concentrated at the top, but recent-year momentum has cooled across the leaders shown, which is consistent with the flat overall trend rather than a single company pulling away.
A single leader well ahead of the field
The top-ranked assignee holds 28 records against a fifth-place figure of 8 and a tenth-place figure of 4 — a steep drop-off that marks this as a leader-plus-long-tail field rather than an evenly split one.
A long tail of smaller filers
Beyond the top 10, which together hold 82.5% of records, the remaining ranked assignees each contribute small numbers of filings — a typical pattern for a specialised measurement-and-materials niche rather than a mass-market cable category.
Corporate-family co-filing is common
The strongest co-assignee pair in the dataset appears 9 times, consistent with related corporate entities filing jointly rather than independent co-invention across separate companies.
Recent-year activity has gone quiet among the named leaders
Every leading assignee tracked for recent-year momentum shows 0 filings in the latest year. Read this alongside the 18-month publication lag rather than as proof the leaders have stopped filing.
| Assignee | Recent year | YoY |
|---|---|---|
| Prysmian S.p.A. | 0 | — |
| Underground Systems, Inc. | 0 | — |
| Loctite Corp | 0 | — |
| Loctite (Ireland) Limited | 0 | — |
| Pirelli Cavi e Sistemi S.p.A. | 0 | — |
| Prysmian Cavi e Sistemi Energia S.r.l. | 0 | — |
| SensorTran, Inc. | 0 | — |
| P & P QUICK SETT SERVICES | 0 | — |
Where to take this
The dataset points to a concentrated but still-active field with specific gaps. Two directions worth pursuing next.
Map the DTS citation cluster in detail
The most-cited records in scope both center on distributed temperature sensing for cable characterisation. Before drafting a DTS-adjacent claim, trace which specific limitations those records already cover.
Explore citation network in EurekaTest claim language against the under-claimed sub-areas
Dynamic rating, grouping-factor correction and backfill thermal optimisation show lighter density than the H01B/G01R core. Drafting a first claim around one of these narrows exposure to the concentrated leader group.
Draft and check claims in EurekaCommon questions on cable ampacity patents
One assignee leads the ranked list with 28 of the 120 records in scope, well ahead of the fifth-place figure of 8 and the tenth-place figure of 4. That gap marks this as a leader-plus-long-tail field: a single company has built a substantial position while 44 assignees in total are ranked, most holding only a handful of records each. Anyone entering this space should expect to design claims around that leader's existing footprint rather than assume open ground.
The filing count held flat at 2 in both 2021 and 2024, a 0% change across that span, after peaking at 6 in 2018. Published counts for 2025 and 2026 look lower, but publication typically lags filing by around 18 months, so those recent years are still incomplete rather than evidence of decline. The honest read is a mature, low-but-steady filing rate rather than a growing or a collapsing field.
Cable and conductor construction (IPC class H01B) accounts for 27.5% of the 120 records in scope, and electric/magnetic measurement (G01R) for 20.8%, making these the two dominant claim bodies. Temperature measurement (G01K, 14.2%) and power grid systems (H02J, 13.3%) form a second tier. Because records often carry multiple IPC classes, connector, circuit-board and optical-sensing elements also appear at double-digit shares, showing that many claims bundle ampacity with an adjacent hardware or sensing component rather than standing alone.
Within this dataset, dynamic rating under real-time load variation, grouping-factor correction for mixed cable bundles, hotspot identification via sensing fusion, and backfill material thermal resistivity optimisation all show lighter claim density than the dominant H01B and G01R core. These are not unclaimed, but they carry less concentrated prior art than cable construction or general electrical measurement, making them a more promising starting point for a narrowly drafted first claim. Confirming density against the specific sub-claim you intend to file remains necessary before committing to a direction.
US9638586B2, assigned to Underground Systems, Inc. and published in 2017, covers a method for generating a wide-area map of earth sub-surface thermal properties by collecting real-time weather and earth data at multiple locations, calculating thermal properties iteratively, and interpolating between locations to estimate properties elsewhere along an underground cable route. It does not block cable ampacity work generally, but it does sit squarely across any invention that infers soil or backfill thermal characteristics at unmeasured points from measurements taken elsewhere. A new filing in that specific mechanism should be checked against this record's claim language before drafting.
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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.
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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.