I took a local license test and it had a question I could not find. It drove me crazy. Maybe someone else might know. #8 or larger must use this type of termination. I don't remember the multi choice. It was like set screw or plate binding screw (not sure). I would like to see this article if anyone knows or can find it.
110.14 (A) "Terminals. Connection of conductors to terminal parts shall ensure a thoroughly good connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors."
Electure— You beat me to the draw. That's the only code reference I could find also. It would follow that the limits put on #10 conductors - upturned lugs etc., would conversely say that #8 conductors could not be terminated like you could a #10 conductor. Kinda tricky but HEY that's what test are sometimes all about.
Greg— I inspect in an area with a lot of high end homes and permanently installed swimming pools and they use the "cups" for hand rails and diving boards etc. The accepted method is as you show with the #8 solid wire onto the cup and usually they will twist the wires in a pony tail type method on the opposite side of the screw. Works well. Some Inspectors question wether or not this is "Listed" for the purpose but I don't think it needs to be no more than any other component of the pool structure. Some will ask for a "Listed" lug here but I don't think it is necessary. IAEI seems to support me on it. I'll try to attach a graphic but I think you know what my point is. http://homepage.mac.com/georgelittle/DCS00010.jpg
We had a long discussion about this on the Fl IAEI BB and the top pictures seem to be the way this was listed as best we can tell. It is very hard to actually find much definite about it. It was clear to everyone that wrapping the wire around the screw and not laying it in the grooves was unacceptable. All it takes is a small twist of the cup to break that screw loose if the wire is not positively secured in the grooves. That will certainly happen when the the concrete guys are positioning it. They fold and twist it around to get it to lay where they want it. Clamped in the grooves, the wire is not going anywhere and you can't put any torque on the screw by moving the cup around. I went around and talked to the guys at the pool company that built my wife's pools with a cup and a couple feet of #8 showing them the difference. It only takes a few seconds and a twist of the cup to demonstrate why the bottom picture is wrong.
BTW simply screwing a listed lug on there does not make this any more secure. You can still twist the cup and loosen the screw. I do think it may actually violate the listing to put a lug on it. Unless someone can show me an instruction sheet with a lug there, I will remain unconvinced otherwise.
How about this http://homepage.mac.com/georgelittle/DSC00010.jpg That kid probably was my niece once removed. The link should be showing the cups and the part that doesn't show is the fact the bonding wire is twisted like a pony tail behind it and the cement contractors probably won't loosen the connection in the process of setting the cups when they pour.
Those cups look fine to me. I am curious about the Spa Flex (2" white LFNC type stuff in the plumbing) but I guess that is not in your area of responsibility. I have heard good and bad things about this stuff being glued into regular PVC fittings and buried. U/L won't list it that way for us. I have always been curious about that. I guess Carlon wants to sell those $2 LFNC fittings instead of the 20 cent RNC glue in fitting so they won't submit it for testing.