I am connecting sets of three #8 wires for a 220 circuit, and have found large blue wire nuts from Ideal that are rated for this wire size. But they are very difficult to twist to the point that the wires themselves begin to twist together, and upon removal the nuts don't seem to have made much of a grab on the wires, or to twist them. The wires are a combination of 7 strand and 19 strand. I see that multipart "Polaris" type connectors might be better, though much more expensive. I also wonder whether the set screws on Polaris (or the Morris that seems to be the same but much less expensive) are subject to backing out unless locked in some fashion. Help greatly appreciated!