A fault claim is any claim resulting in your own insurer being liable (paying for the claim). For example, a theft claim is a fault claim. Even though you may not be to blame, your own insurer would be liable because there is no other party to recover the costs from.
If your insurer pays for your damages in a claim where a third party is to blame, but then re-coups all their costs via the third party’s insurer, that is a non-fault claim because your insurer was not liable (recovered their costs for the claim).