A system and method for fault detection including a transmitter adapted to transmit a composite signal on a buried cable so that fault leakage of the composite signal returns to the transmitter through the ground surrounding the buried cable. The carrying device has a plurality of holding members that are capable of securely holding several heavy items, such as plastic bags filled with consumer goods, for easy carrying by a user of the device. The first-step protruding portion of the cover thereby slips out from a hooking state. If a determination is made that a new resource is needed, either by the customer or by analysis of the customer resource data and rules for purchasing new resources, then a purchase request is sent to the vendor for the new resource.