The Measurement of Smoke Production From Electrical Wires Under Conditions of Current Overload

摘要

A significant fire hazard presented by electrical wiring is smoke generation resulting from an electrical fault which has caused a condition of current overload. In many cable specifications the requirement for 'smoke from current overload' is simply that there shall be no visible smoke when the conductor is maintained at a specified temperature. Such a test provides no quantitative data and provides very little information about the smoke producing potential of the wire. We have developed a test which measures the smoke producing potential of electrical wiring over a range of overcurrent conditions and which therefore allows comparisons to be made between different insulating materials and constructions. We have also compared our results with those obtained from a conventional smoke test which uses external heating to degrade the insulation. Tests have been carried out on a number of different electrical wires. Results show that the test is simple to carry out. The thin wall wires tested produced low levels of smoke in both the current overload test and in the conventional test.