When attaching wires to the side screw terminals of an outlet or switch (i.e. device) I had learned to form a J-hook and slip it under the screw head with the hook orientation following the clockwise direction of the screw when tightened.

However I've noticed a lot of wiring devices now seem to be designed to prevent the J-hook from being looped over the screw. On the left side of the screw there is sufficient space to slip the correct wire gauge down under the screw head, but on the right side where the end of the J-hook would land is much narrower, this prevents the hook from being slipped over the screw head. It looks like this is by design.

O.K. so back the screw out enough to gain enough space on both sides of the screw head in order to slip the hook under. But when trying to back the screw out at some point turning the screw becomes extremely difficult, almost like it hit a limit by design. The amount of force needed to back out the screw to open enough space to slip the hook under the screw head on both sides of the screw head seems excessive.

Why do these devices have different wire clearances on either side of the screw head and why does backing the screw out seem to hit a limit?

Do I have a misunderstanding of how to attach a wire the side terminals of a device?


Yes. Those misfeatures are actually features. They are designed to help you keep the wire captive and in the right place.

First, there is a hook designed to hook the existing wire (i.e. the short on the right side) to help you make the J-hook more than 180 degrees to make it captive on the screw. The idea is now, you don't need to use a needle nose pliers to make that final over-180 bend. This won't make any sense if you're making the J-hook too short to benefit from this feature.

Second, it helps keep the wires "trapped" under the screw, so you don't have it slip out from under and fail to notice it if you are working quickly.

This "Trapping" is especially helpful when using stranded wire, which tends to squish around and fray when tightened. I use a lot of stranded wire, and those things are a godsend. As the screw gets nearer to bottom, these gates will fully entrap the wire so it can't frizz out of the hole. You still need to give the strands a really sincere twist, but it helps.

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