NocTec is a rare Runeword created by combining a Noc Rune of Ritual and a Tec Rune of Invocation.
How to Create NocTec
You can create NocTec by adding the rare Noc Rune of Ritual and the magic Tec Rune of Invocation to a two-socketed Helm, Chest Armor, Pants, or Two-Handed Weapon.
Noc - Inflict a Crowd Control that isn't Slow or Chill. (10)
Tec - Invoke the Barbarian's Earthquake, dealing damage to enemies within. (100)
Overflow
NocTec can not overflow because the amount of Offering you receive from the Noc Rune exactly fills the required Offering of the Tec Rune.
Overflow occurs when your Ritual generates more Offering than required for the Invocation. The overflow effect is proportional to the amount Offering overflows.