According to this forum post the internal cooldown for weapon enchantments is around 4 seconds:
Eso picked the internal cooldown system and the actual cooldown is around 4 seconds, so your fire weapon will trigger the fire damage effect every 4 seconds of u attack.
The enchant on this set, will now reduce this cooldown by 1 second, so it can trigger every 3 seconds instead of 4.
On my level 40 Templar I have these two weapons equipped, one on each weapon set:
- Hickory Bow of Frost, with a +290 cold damage enchantment
- Wolfpack Staff, with a reduce target weapon damage by 38 for 5 seconds
Let's say I open my fight with the healing staff (Wolfpack Staff) to reduce target weapon damage and then quickly switch over to my bow for dps, will it proc right away or wait 4 seconds, or is this entire proc business entirely random but cannot occur more often than every 4 seconds?