Arc mapping can be used in scene where the traditional fire patterns are unclear such as when the level of destruction is too high to enable determination of the origin of the fire. The electrical installation within a property can be examined for signs that it was electrically active at the time of the fire. The examination of the whole installation from a fire damaged room and any appliances from the room can give a three dimensional ‘map’. This arc mapping gives a pattern of the damage which can be interpreted to determine where the electrical installation was first attacked and so the area where fire started. This examination is microscopic and so undertaken in the laboratory however, we will visit the scene in order to understand the electrical installation and to ensure the cables are packaged and transported appropriately to enable the arc mapping to give an accurate depiction of the scene.
This is an incredibly useful technique to employ when the room of origin has become fully involved in fire which may leave confusing patterns of burning.
Typical evidence identified during arc mapping: beading on one conductor
Typical evidence identified during arc mapping: a notch caused by a loss of copper from a conductor