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Molten thermoplastic dripping behavior induced by flame spread over wire insulation under overload currents
Hao He1, Qixing Zhang1, Ran Tu2
1State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
Journal of Hazardous Materials
|August 10, 2016
Summary
Molten thermoplastic insulation drips from copper wire under overload currents, a key factor in energized electrical wire fires. Dripping frequency is proportional to the square of the overload current.
Area of Science:
- Electrical Engineering
- Fire Science
- Materials Science
Background:
- Energized electrical wire fires pose significant risks.
- Understanding molten material dripping is crucial for fire safety.
- Polyethylene insulation behavior under thermal stress is understudied.
Purpose of the Study:
- Investigate molten thermoplastic insulation dripping from copper wire under overload currents.
- Analyze the relationship between electrical current and dripping behavior.
- Evaluate the impact of dripping on flame propagation.
Main Methods:
- Theoretical analysis of wire temperature profiles under overload currents.
- Laboratory experiments measuring drop formation, frequency, and falling speed.
- Developing a model correlating molten mass loss with volume variation.
Main Results:
- Overload current is essential for initiating wire dripping.
- Averaged dripping frequency is proportional to the square of the current.
- Molten dripping significantly influences flame width, height, and spread velocity.
Conclusions:
- The study provides critical insights into energized electrical wire fire dynamics.
- Quantified relationship between current and dripping behavior aids in fire risk assessment.
- Dripping molten insulation is a key factor in flame propagation.
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