http://www.uesp.net/wiki/Morrowind:Disintegrate_Armor

Disintegrate Armor/Weapon on self deals no damage, but casting it still trains destruction.

That source indicates that Disintegrate Armor on self deals no damage, however, that's not necessarily what happens in my game. Disintegrate Armor on self does damage my armor. So I'm curious to know about something. Is the source wrong?

One thing I see that could have happened with that page is that they bundled up Disintegrate Armor and Disintegrate Weapon on self. Disintegrate Armor on self appears to work, but Disintegrate Weapon on self does not as you don't have your weapon readied when casting said spell.

So basically, I just want to confirm that Disintegrate Armor on self dealing damage to your armor (I.e. It works) is vanilla behavior o.o ...

Hmm it seems it may just be poor wording. They may mean it deals no "health damage", but the way they have worded it is fairly contradictory. i'll test this next time i'm in game.

I did some further testing, and I could see why they may have concluded that it doesn't work. For some reason, in it's spell form, it needs a high magnitude for it to work. With low magnitudes, it appears to do nothing. With enchantments, low magnitudes do work. However, it seems like with extremely low magnitudes (1-1 for example), there's a chance it won't do anything (Also a chance it will damage the armor).

I imagine that there's a mathematical formula somewhere behind the scenes, but I'm not sure of what it contains.

So to summarize, it appears as though there's some instances where Disintegrate Armor on self does not work, but it appears as though there is also some instances where it does work. Please feel free to correct me if I'm wrong. o.o

PS.
I found that Disintegrate Weapon on self also works if you enchant a weapon with it and make the enchantment type to be cast on strike.