Abstract: As a primary means of electrical transmission, high-voltage cables play an indispensable role in urban and industrial areas. Hence, investigating the fire safety of high-voltage cables holds significant importance in academic discourse. Using 110 kV flame-retardant cables as experimental materials, fire spread experiments were conducted under varying spacing conditions, during which flame morphology, flame radiation, mass loss, and cable temperature were measured and analyzed. Based on the evolution of fire spread morphology over time, the process can be divided into four stages: ignition phase, spread development phase, stable combustion phase, and extinction phase. During the extinction phase, the phenomenon of flames moving along the cable surface was observed. The total mass loss of the cable, mass loss rate, and flame radiation exhibited a trend of first increasing and then decreasing with the increase in cable spacing, reaching a peak at a spacing of about 4 cm. Moreover, the experiment found that the average temperature of the cable's outer sheath decreased exponentially with the distance from the center of the fire source. This study provides precise data support for safety assessment and fire control for 110 kV cables.

Key words: cable fire, fire spread, cable spacing, mass loss, flame radiation