Electrical boxes and panels may have a sharp edge where wires enter the box. Occasionally the wires insulation may be damaged or partially scrapped off from the sharp metal edges of the box.
To prevent this electricians often use wire clamps, special connectors or bushing’s.
Arching or Breaker Tripping
When the insulation is damaged and part of the metal wire is exposed, then arching may occur between the wire and the metal edge of the box. When there is arching there usually heat and occasionally a fire may occur.
Breakers may trip when arching occurs or the wire comes into contact with the metal electrical panel or J-Box.
Should this condition be discovered, it is wise to check the wire for any damage to the insulation and then install a proper wire clamp, connector or bushing. Nearly all home inspectors and electricians will recommend reviewing this condition and corrections as necessary.
Wire clamps, connectors and bushings are inexpensive and generally easy to install.