Degradation Pathways of Electrical Cable Insulation: A Review of Aging Mechanisms and Fire Hazards
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript presents a review on the research concerning electrical cable insulation degradation. The article is clear and reasonable. However, several issues should be addressed to improve the quality of the manuscript as follows:
1 The bibliometric analysis based on 217 publications identifies four main thematic clusters through keyword co-occurrence mapping. The interpretation lacks sufficient depth regarding the interconnections among these clusters and their implications for current research trends.
2 Some figures are blurred to meet academic standards, such as Figure 1 and Figure 3.
3 Authors should carefully check the manuscript for writing issues, such as the repeated abstract and the formatting of equations.
4 In Section 3.2.1, authors note that thermal conductivity may temporarily increase under certain aging conditions. The practical significance and prevalence of this phenomenon under real-service conditions are not sufficiently addressed.
5 Although the article cites a large number of experimental results and tables, the comparative and critical analysis between different studies is insufficient.
Author Response
Response to Reviewer 1 comments in the attached doc file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors carried out a comprehensive literature review on the degradation pathways of polymeric electrical cable insulation materials and their connection to fire hazards. They assessed over 200 publications, with focus on how thermal, electrical, mechanical, and environmental stressors progressively impair dielectric strength, thermal stability, and mechanical integrity. The review also focussed on examining combustion dynamics in aged cables, looking into details such as altered HRR, smoke production, and flame spread. The review also looked at changes in thermal conductivity and dielectric properties, comparisons between natural and artificial aging and explored the impacts of flame retardants during aging. They performed bibliometric analysis on 217 retrieved publications, and used analysis to identify four thematic clusters (thermal/electrical aging, fire performance, etc.). The review also integrated experimental findings from cone calorimetry, TGA, FTIR, UL94 tests, and field studies.
The structure is logical and comprehensive and provides a clear link between aging processes and fire risks. The review highlighted that material aging is not simply a material failure, but a fire initiation precursor. The review is also of strong relevance as it can be used to improved diagnostics and modelling in safety-critical sectors like nuclear plants. However, it occasionally prioritises breadth over depth, with some sections feeling a bit more descriptive rather than analytical, and lacks a strong emphasis on emerging technologies (e.g., AI for prediction). Also, while the bibliometric approach was objective and allowed for visual mapping of research trends and gaps comprehensively, the reliance on Scopus articles may have excluded non-indexed sources (there was also no sensitivity analysis on bibliometric parameters).
Scientifically, it is rigorous in citing recent and relevant studies but could better address conflicting evidence or methodological limitations in the literature.
It was found Insulation aging lowers ignition thresholds (e.g., 30% reduction in delay for thermally aged XLPE), increases peak HRR and smoke toxicity, and promotes flame spread (e.g., up to 50 m/h in vertical trays). Thermal conductivity was found to decline non-monotonically, dielectric properties degrade, flame retardants (like ATH) retain efficacy, but others lose it via migration or decomposition. Service lifetime was found to shorten from 40–60 years at 90°C to 7–30 years at 95–105°C.
Overall, the manuscript is well-structured and links insulation degradation to fire hazards in electrical cables.
Positives:
- The keyword co-occurrence map (Figure 1) is a valuable addition. It enhances objectivity and ensures clarity for the reader, but the query's conservatism may overlook emerging terms. In future studies, the search could be expanded to include more literature from diverse sources.
-Figures are all clear and relevant. The detailed explanations are also clear, and well explained and contribute to the overall quality of the research paper.
-The reviews use and focus on evidence-based synthesis, recent citations (mostly 2018–2025), and avoidance of unsubstantiated claims demonstrate good scientific rigor.
- Comprehensive in scope
- Bibliometric map identifies underexplored areas, mathematical models add analytical value.
-Emphasises real-world implications (e.g., nuclear cables), with clear tables for quick reference.
- Highlights gaps and future directions effectively.
Corrections/specific comments:
-Concepts are grounded in well-explained scientific principles, but the review ends with an uncritical acceptance of study findings—e.g., no discussion of sample size biases or reproducibility in experimental references.
- Equations (1–7): Define all variables upon first use for clarity.
- Grammar/typos: E.g., "deterioration" misspelled as "deterioration" in places
- The review sections feel unbalanced- expand mechanical/environmental mechanisms with more examples.
- A few more sentences critiquing the study limitations would be useful (e.g., lab vs. field validity).
Author Response
Response to Reviewer 2 comments in the attached doc file.
Author Response File: Author Response.pdf
