Glyph of Hand of Sacrifice

30% of 2.500.000 = 750.000
So in order to reach the cap (in this case 750k HP), the boss have to do 2,5 mio dmg.

Setokaiba wrote:2.5 mmillion? teh health cap is paladins HP, which is around 900k?
Yeah I know to break that cap early is quite hard, but tanks do get smashed in some encounters.

The damage cap is compared to the damage that is actually transfered via HoSac (30% of boss damage) and not the damage the boss does (100% of boss damage).

This was stated above by Minyatur, but if you need math to support:
Paladin with 750k HP
where d = damage done by boss:

0.3*d >= 750000
d >= 750000/0.3
d >= 2,500,000

for Paladins with 900 HP:
d >= 900000/0.3
d >= 3,000,000

The dtps conversion factor would be:

dtps >= (h/0.3)/12secs
dtps >= (1/3.6)*h
dtps >= 27.78% of caster's health

If that condition is met for 12 seconds, then hand of sacrifice would cap.

I'm not far enough into content to know any bosses that do that much damage (at least consistantly for a period of 12 seconds), so I was curious if it was. I've seen some hard hits, but nothing that lasted long enough to limit HoSac yet. Do later bosses (Garrosh for example) put that much dtps out?

I've not got to it myself yet, but if you're letting the other tank solo Malkorok's Blood Rages you might get to the cap.