Sometimes problems are due to operator errors. All 6 of my digital outputs on the T3 stopped working one day last week. The LED’s lit up but there was no (or intermittent) continuity between the screws. I thought I burned out the relays. In actuality, I had changed some of the wiring on the analog screws earlier in the day. The terminal strip for the digital inputs was not firmly seated and I accidentally loosened it further while changing wires. I did not discover the problem until I started to replace the hardware with a back-up T3.
So the moral of the story is to check your terminal strips before you assume your T3 has gone bad.
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This type of screw terminal connection is also prone to becoming loose and wires coming out. Ferrels help a lot.
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TD was saying the terminal block itself wasnt seated correctly which could happen regardless of the type of terminal.
For reference, we use the ‘rising cage’ type terminals similar to Tab2 which clamp the wire down flat. These are more expensive than the spring type at Tab1 which tend to push the wire out over time. The only thing to watch out for with the rising cage connectors is that the cage should be in the down position when you insert the wire. Ferrules would help, agreed.
Also: would be interesting to check out the screwless clamp type at Tab3 on a few products around here. Not sure how they would fare with stranded wire though.
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With the Push ins, You can use ferrules if you are worried about the strands. There is a round crimper and a square crimper. These terminal blocks are pretty much insert and forget.
The rising cage type come in all sorts of different qualities. Most of my customers and UL508 require that they are torqued. They generally wont reach torque before they strip. And if you release the torque, the cage is deformed and wont accept another torque. Ferrules help a lot with them too.
Just Saying.
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