I thought power armor negates what yoh wear under it.

That hapened in three and new Vegas. You would get raiders looting fallen BoS and wearing the armor.

I don't know about it negating... if it did, then my carry weight would have changed because I have the mods on my armor that add carry weight. I always see it increase when in armor to I think 50 more or 100 more than what my maximum was.

I don't think you needed training in fallout 1 or 2 to wear power armor.

I currently have four power armors at the Sanctuary. Every time I find one in my travels, I take it with me.

Must collect them all!

The question now is seeing as things respawn will raiders in PA comeback to be looted again. It doesn't much matter as there are plenty of frames and plates and neither sell for much money so there are better things to farm. I did notice some other 'things' respawn.

That is because you are wearing power armour which is powerful and therefore allows you to carry heavy things. The carry weight mods on your normal armour are negated, but it doesn't matter because the power armour itself gives a hefty bonus to carry weight. Of course if you have carry weight mods on all your armour pieces then the carry weight bonus from the power armour would feel less significant.

Just completed the full set of X-01 power armor a couple of days ago. It's beautiful. Don't skip on changing the headlamp either. Do it, then look at yourself in third person mode.

mother of god...

Between pickpocketing raider fusion cores and merchants outright selling power armor frames, power armor is infinite. The Atom Cats have restocking frames, T-60 pieces, and cores btw. If you want free T-60 pieces, just pay attention to the vertibirds crashing all around. When one crashes, rush the crash site and loot the dead knight.

I haven't done pickpocketing or merchant purchases yet and my collection of power armor is up to 13. There are at least that many you can find in the wastes and I haven't nearly explored everything yet.

X-01 parts might be more limited ... I've found two static suits in the world both with some X-01 parts, but missing a few. Combined, they form a full set with a few pieces left over. I've heard there is a place with a fully intact X-01 suit but I haven't found it. That would lead me to expect you can at least form two entire X-01 suits. I don't know if there is a limitless supply X-01 parts anywhere (ie, chance in a loot table for a respawning enemy).

I have around 10-11 suits. Many of them have broken pieces, but they're there. Stuck em all into the Red Rocket garage. Will likely put them on the roof.

That fully intact set is easy to get too... Just follow a signal, kill a few annoying Gunners at the place, and hack a terminal. I just found it earlier today while exploring myself. I now have full sets of at least three types. I'm missing a full T60 and a full T51 set. I only have a T60 torso and am only missing an T51 helmet.