Electrical – Was this caused by arc flash or just short circuit without any arc flash


Can the following be caused by short circuit without any arc flash? There was an initial short between lugs and chassis. Did arc flash occur that caused the lugs to melt. Or can it melt just by the huge current during the short circuit?

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In the above. The live wire was lowered by the electrician to the terminal. Then somehow it shorted (between the 208v wire and neutral/chassis ground) causing the breaker lugs to melt and a hole to be produced at the chassis at the back. This also caused a rat size 2nd degree burn in the electrician arm. Was this caused by short circuit without arc flash or was it arc flash?

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Best Answer

Most probable casue was a bad contact, it wasn't tighted well. I can see the healthy connection next to it - it's a wrong connection. The wires has to reside in the bottom of the lug, tightening the screw you compress wires and bottom of the lug.

The wire lost contact with the lug, but the distance from lug and wire was so small, that the electric field easily break the air, making an arc. This resulted like everthing is OK, the current was flowing and the appliance worked, but with help of an arc.

This is also one of the causes why houses get on fire.