checking wire termination torque
checking wire termination torque
(OP)
I have been getting conflicting information on checking or re-torqueing a wire termination. I have been taught that this should never be done due to the cold flow or relaxation that occurs over time. This relaxation has been accounted for in the original torque specification. If you check the torque by re-torqueing to the original value you will make the connection to tight and when the conductor heats up on high loads the pressure due to wire expansion will cause additional cold flow that may result in high contact resistance when the wire cools and had a low load.
Others have told me that the wire terminations should be re-torued to the original value at least once a year.
Anyone have any comments?
Don(resqcapt19)
Others have told me that the wire terminations should be re-torued to the original value at least once a year.
Anyone have any comments?
Don(resqcapt19)






RE: checking wire termination torque
wbd
RE: checking wire termination torque
Don(resqcapt19)
RE: checking wire termination torque
It has been my experience over the years that in the case of aluminum conductors that this is done as a part of a maintenance program when the gear is shutdown such as a yearly turn around, however usually only on larger cable size ie; 4/0 and larger. However in the case of copper if the original installation was torqued properly the re-torquing when called for usually shows no "loosening" of the conductors.
Troy (troyster)
RE: checking wire termination torque
I know that it has been commonly done, but I've been told it shouldn't be done and actually makes the connection worse then it was before it was re-torqued. I'm trying to find out it what I've been taught is actually correct. If what I've been taught is correct, then there are a lot of PM programs that are making problems worse rather than better.
Don(resqcapt19)
RE: checking wire termination torque
RE: checking wire termination torque
My point is that the original torque specs account for the relaxation due to ambient or load induced temperature changes. If the connection is re-torqued, it becomes too tight and there will be more cold flow from the temperature changes resulting in a connection with too little contact pressure to carry the load without excessive heating. A connection should never be re-torqued, unless there is evidence of a problem. If there is evidence of a problem the conductor must be cut off and the new end inserted into the terminal and then tightened to the original torque spec.
RE: checking wire termination torque
RE: checking wire termination torque
Those types of devices are used on terminal to bus and bus to bus connections, but what about mechanical wire terminations where the set screw directly contacts the conductor?
Don(resqcapt19)