Damage taken from mana before life.

I have a question about Damage taken from mana before life :

When you have ES, does damage take mana before taking ES too ? Or does it work only when ES is depleted ?

Damage to life is what matters for those modifiers. ES prevents damage to life. You could take %damage penetrates ES to spread incoming damage between ES and mana at once. Before it was destroyed, EB was the better option to use mana as both defensive and offensive resource.

thanks !