A fault claim is any claim resulting in your insurer being liable (paying for the claim). For example, you are not to blame for a theft claim but your insurer would be liable, as they have no other party to recover the costs from.
If your insurer pays for your damages in the event of a claim, for example where a third party hit your vehicle, but then re-coups their costs via the third party's insurer, this would be a non-fault claim as your insurer was not liable.