Note these comments refer to mechanical wire terminations and not buss bar connections or connections between a wire connector and a buss bar. The materials involved in these connections are harder and do not behave in the same way as wire.
All torqued connections relax over time. This relaxation is accounted for in the original torque spec.
If the connection is too tight, the wire has more "cold flow" and is extruded out of the connection. This is made worse with heavy cycling loads where the heat causes the wire to expand and produces even more cold flow. This will in some cases eventually result in a high resistance connection and failure.
In my opinion the same effect happens when wire connectors are retorqued as when they are over torqued.
Under torque also will result in a high resistance connection over time. With an under torqued connection, excess heat is produced at the connection and the wire expands causing cold flow and as this cycle repeats the connection get worse and at some point it will fail.
I was taught never to retorque a connection. If the connection is showing early signs of trouble, the wire should be removed from the connector, cut off, stripped and installed in a new connector with the correct amount of torque.
Don
