http://us.battle.net/d3/en/class/wizard/passive/dominance
The effect can stack 10 times. Does that mean it can cover 24k80k damage on it's maximum stacks?
Killing an enemy grants a shield that absorbs 2477 damage for 3 seconds. This effect can stack up to 10 times.
Refreshing Dominance will set the shield to its maximum possible potency and each stack will increase its total duration by 0.5 seconds.
It seems that thge shield absorbs 2477 and refereshing dominance will set the shield to its maximum possible potency, which is 2477.