Wire splice for Top leg
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This wire splice connection was found to be showing some heat. The temerature here is important but it is not really showing all that hot.
 
The concern here is the fact that the other two phases are much cooler than the one showing the heat. All three phases are getting the power from the same source and going to the same motor, therefore they should be close to the same temperature. If they are not then there is a problem somewhere. Notice that the splice showing the highest temperature and the wire cools off the farther as it gets from the splice. This would indicate that the splice is bad. It should be taken apart and cleaned the re-spliced then watched to be sure it stays cool.