Tastes great...less filling.
There is no requirement to twist, nor is there any prohibition.

Here's an old thread about the twist debate.
But, brickeyee pretty much summed it up. Some people prefer to do it, some don't.

Here is a link that might be useful: Old thread with the twist debate

OR - you could use a push-in type connector and eliminate the need for the twist or don't question.

unclebill, there was also the great debate over the push in connectors too...

Here is a link that might be useful: push in connectors thread

One factor missing from the discussions is that, imho, a properly twisted splice will help eliminate electromagnetic interference in the building. When the X10 radio frequency-controlled switches first came out, I became sort of an expert in de-bugging them, as they had significant problems with spurious operations. When that happened, 9 times out of 10 I was able to fix it by ensuring the entire system had proper, twisted splices. However, it was primarily the push-in receptacles that caused the problems, since the push-in connectors were not in use then. Still, I use only twisted splices because I've seen too many problems when splices were not done right.

I have never heard of such a thing. It's not that I doubt your word, it's that I can't imagine a mechanism by which it would operate. Anyone?

Yeah, I know about the "debate". As far as I'm concerned there isn't one. I haven't see a push in fail yet. I've been in several of the high tech electronics manufacturing companies locally that spec. the electrical down to the smallest detail - they used push ins on all the #12 in the building. I've installed thousands with no issues.

I don't pre-twist, either

As to the X-10 issues, most of the problems I see are cured by an incoming line filter, a line-to-line coupler, and, occasionally, a booster. If there's no noise that you can hear on a clear channel with a cheap AM radio there's probably nothing that's going to bother the X-10 power line carrier control functions, or the low power radio remotes and switches. That said, X-10 modules near switching power supplies and attached to/downstream of a GFCI sometimes have issues due to the fact these devices attenuate the signal to sometimes unusable levels. Unless a wire wasn't wrapped into the bundle of wires in the wire nut I've never found twisting one to improve X-10 issues, but I've only been using X-10 20+ years so maybe I've been missing something.

whats an x-10?

Bill: it's not so much the twisting that helped, rather it was just using anything else other than the the push-in type receptacles. This was all 20 years or so ago, so I'm sure things are different now. But in those days the X10 devices were more sensitive to problems than now (I think they later installed the line filters you mentioned right in the device) and the then-new push-in receptacles were not as good as they are now (for instance, they used to offer 20a push-in receptacles, but no longer). I have never used the push-in type connectors, but from everything I've heard and read, they seem to work fine. I just have no personal experience with them, unlike the push-in receptacles.

radioguy, check this link:

Here is a link that might be useful: X10

"...push-in receptacles were not as good as they are now..."

They are not any better now, they just failed miserably on 20 A circuits.
Use the screws or a back fed clamp plate device.
The simple 'push in the bare wire' type still fails all to often.

Yeah, I'd buy the receptacles with the backstabs causing problems on X-10 stuff as they cause them on everything else, too.

A guy on another forum refers to backstabs as "profit holes". I call them "profit twice holes" - once on the install and again on the repair.

Just as a side note, the X-10 patents expired and several companies make PLCC devices, some compatable, some not. Most of them are much better than the first generation stuff