can someone tell me what wire arcing is?
is there a wire arcing to something?? is there a potential (voltage/current) on the wire? if the voltage exceeds the wire insulation, it can arc to a lower potential, usually something that is at ground (0) potential. if the insulation has been reduced due to chaffing or cut through, it can arc to a lower potential. now that we still need more info, we think that your wire arcing is electrical current going from one potential to another.
It's when you get two wires (or any conductors) close enough together with a large voltage difference where the electricity will jump through the air from one wire to the other instead of staying inside the wires and following the regular electrical circuit.
Arcing occurs not only because two conductors are near each other, and having a voltage potential between them. It occurs (as in a switch) often when a conductor is carrying a load, and the the current is interrupted. It can range from just a tiny spark, to an arc which gives off enough energy to start a fire. Switches and switchgear attempt to minimize this arcing by making the separation of parts quickly.
A very complex subject! Generally, the arc itself is a small area of plasma between to conductors at different potentials.. If the wires never touch, a high potential/voltage is required to get it started. Once initiated, the voltage across the arc becomes quite low (around 20V) even at high currents. There are many other interesting features like the arc impedance has an area of negative differential resistance. Arcs in house wiring are categorized into to camps. These are series arcs and paralell arcs. Series arcs are those that are in series with the load. They happen when a wire breaks and starts to separate. As the wire pulls apart the arc strikes and a plasma is initiated. These arcs are low in current (below the breaker's rating) and will not be detected by the circuit breaker. They can persist for a long time just sizzling away and can start fires. Parallel arcs are when the line and return wires have insulation failure and short together. They tend to have very high currents and quickly either blow themselves open or go to a 'bolted' fault (hard short circuit) and trip the breaker. They too can start fires in spectacular fashion. As I said, its very complex and I could go on for pages ... I worked on arc research for a number of years trying to devise ways of detecting arcs back at the circuit breaker box using current and voltage signatures. It should also be mentioned that arcs act very differently with AC voltage verses DC voltage. AC arcs tend to extinguish at the 60Hz crossovers (when the current is zero) and must be restruck each cycle. Because of arcs, and recent research, you will now find special circuit breakers on the shelf at your local hardware store that have extra capabilities related to detecting arcs. If there is a specific question that you have regarding arcs, post more details or send me an email.
