The present application discloses an upgradeable cochlear implant. In one example, the implant may include a stimulator configured to generate a stimulation current comprising at least one stimulus, a first lead configured to conduct the stimulation current from the stimulator to at least one electrode, and a second lead configured to allow connection of a separate module to the stimulator. The second lead may include a lead conductor, a reference electrode configured to collect the stimulation current, an electrode conductor configured to conduct the stimulation current between the reference electrode and the stimulator, and an insulating material surrounding at least the lead conductor and the electrode conductor. The reference electrode may be formed at an exterior surface of the second lead, or may be formed on a portion of a connector for connecting to the separate module. The implant may additionally include a protective element.
