A fire started on a welding cable joint

1. Accident Process

A factory welder was welding in the woodworking workshop. A wet sack covering the workshop window fell on the welding machine cable joint. After the welder worked for more than 2 hours, thewelder turned off the switch and went off work. As a result, the sack caught fire at night and caused a fire.

After the accident, a simulation experiment was specially conducted to analyze the cause. Five layers of dry sacks were covered on the original joint. The welder worked for half an hour and the sack caught fire! The experiment with wet sack pieces showed steam after 1 hour, light smoke after 2 hours, and fire after 5 hours!

2. Analysis of the main causes

Because the joint of the welding cable was not firmly connected, the contact was poor, and the contact resistance was too large. When the welding current of several hundred amperes passed through the joint, the resistance heat generated caused the sack to catch fire and caused the fire.