What key British/international cable fire test standards exist, and how do their methodologies differ?

Cable fire safety is governed by specialized standards with distinct protocols:

• BS 6387 (≤20mm cables): Features 950°C/3-hour "C test" (sustained resistance), 650°C "W test" (flame+sprinkler), and "Z test" (950°C flame+30-second shocks), using 500V circuits to verify conductivity.

• BS EN 50200 (European harmonized): Employs 842°C flame impingement with backboard shocks, Annex E water/fire/shock sequences, and PH15-PH120 endurance ratings (15–120 minutes).

• BS 8491 (>20mm cables): Uses radiation-based testing, with thermal parameters partially undefined in current specs.

Divergences in temperature thresholds, duration, and mechanical stress reflect application-specific safety needs.