Print away but always remember that what I am writing down is my observations and details about the code I remember and fairly well understand - at least I think I understand enough about. It is not the word on cable or plugs as everyone has their own interpretation of what the NEC actually means to them, much less what is reality. I tried SJE cable for instance, while Coleman brand seemed to be better than others, I still went back to the normal rubberized SJ cable. Other people might have different opinions beyond cost on said cable. Some might also rather the wire melting down so you can physically see what has been exposed to too much heat, verses what has lots of heat but does not show any damage in the case of grade SJ.
Than there is the grey area. What you can get away with or use in general without problems. Can you use SJ cable in the control booth or for clip lights back stage for instance? From my interpretation of the NEC even where I work we break the rules by using junior grade cable on cable drops or along floors. The crew chiefs ***** and moan that I would keep the heavy cable in stock, on the other hand, it’s the stuff they are supposed to be using on the floor or anywhere else not supported by the truss. It’s in stock but not used much properly. What’s the difference between a box truss and a truss first electric than? If you have a rock concert in a theater which system of cable are you forced to use? Lots of grey area, what I outline is a very general guideline for cable. If in school, you should be using the SO wire. If not it’s a major grey area.
On plugs something I forgot with the Union plug was that between the wires, tinned wires and even the wire washer that others might be able to come up with a better history of, any of them once the strain relief fails will tend to unscrew the screw terminal holding them down. Wire is wrapped around the screw in a clockwise way so as the screw it tightened it will draw the wire into the terminal rather than push it away as it gets tighter. Problem comes in and a problem that is much more simple than settling of any conductors is once the strain relief fails, all the tension on the cable is held be the terminals screws. Once the wires pull, the screws also will loosen causing a high resistance heat connection that will heat up causing the insulation over the conductors to fail, and one that can burn up on it’s own with arcing in the loose connection.
Simple and something of important detail I did not think of at the time, I’m sure amongst many details I did not understand or consider thus this is a single person’s view on cable plugs and installation, but not the Law as it were. If you can learn from what I write, great that is the purpose, but still and always seek out other channels for learning and practice. Once you learn from me and others, than from books an practical experience you will be better than most in the industry in becoming able to study your own observations and forming your opinions to pass on to others. People taught me, I pass it and what I add to it on just as they did.
Hope it helps but it’s not a law or absolute standard. Others on all I write are asked for in gaining a more broad sense of what is really going on or the history of it.
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