Why Does An Electric Arc And Fire Occur When A Wall Switch Is Turned Off?

When a switch contacts disconnect a energized circuit, if the voltage and current do not decay promptly, the current may cross the momentarily separated metal contacts, forming an electric arc. An electric arc is a phenomenon where current briefly jumps through an insulating medium (such as air), generating extremely high temperatures and heat.

The high temperature generated by the electric arc can rapidly damage the internal structure and surrounding materials of Wall Switch. When it occurs for a long time or repeatedly, it can cause the insulation layer to carbonize and the combustion-supporting materials to decompose due to heat, thus creating a source of fire in the wall environment. The arc temperature can far exceed the heat resistance limit of ordinary household electrical wire insulation materials. This heat, concentrated in a very small space, causes localized overheating of the switch and wiring.