If wires won't stay in holes after tightening screws can I just wrap around screws instead
It sounds like you are using a higher quality outlet that has "screw-and-clamp", where you insert the wires into holes in the back and screw down the screw to clamp the wires.
Like a lot of people, you are wildly underestimating how much screw torque these require to clamp the wires.
In fact, you're probably wildly under-torquing all your screw terminals.
One thing that science discovered in the last 20 years is that screw torque really matters on small connections. Failing to tighten enough (or too much) results in arcing and sparking at those terminals, with outlets heating up and even starting fires. Because of this problem (and other science that showed pro electricians couldn't set correct torques any more accurately than their spouses), NEC 2014 now requires you use a torque screwdriver to tighten the screws to the spec on the device labeling.
So it sounds like you're normally tightening screws rather limp-wristed, and you're leaving a trail of time bombs behind you. You should get a torque screwdriver and use it, and if you won't listen to that advice, at least get a Robertson screwdriver (they hold better than Philips) and tighten them Really Super Hard.
You will find that will solve your clamping problem, and you should make a point to revisit your past work and re-torque. Otherwise you'll have problems later.
Yes you can.
If the screws are suppose to tighten/hold the wire in a hole, but doesn't, I would be concerned.
Some outlets just have basic spring tighten holes, these are usually known to give problems, and the screws are the recommended choice.
With outlets being quite inexpensive, if one is not working right it is a lot better just to get a new one, a bad outlet can burn down a house.
The holes are colloquially referred to here as "back stabs". They are convenient but only work under a very limited set of circumstances:
- Correct wire size - typically 14 AWG. But many circuits (even, legitimately, with 15A receptacles) will be 20A circuits with 12 AWG wire.
- Solid wire (as opposed to stranded)
- First use - If you pull the wires out to fix something and put the wires back in, they will not hold properly.
As a result, using the screws is the recommended method. With basic receptacles (and switches) you have to make a hook in the wire, loop it around the screw and tighten it. With better quality receptacles you get screw to clamp. With this, you put the wire in straight and tighten the screw down. And you get two locations on each screw, so if you need two wires you have more options (with the basic receptacles you have to do one in a screw and the other in the back stab - if you can use the back stab at all - or go to pigtails and wire nuts.