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electrodes as permitted in Section 250-52(c) or (d), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than No.6 copper wire or No.4 aluminum wire. (b) Connections to Concrete-Encased Electrodes. Where the grounding electrode conductor is connected to a concrete-encased electrode as permitted in Section 250-50( c), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than No.4 copper wire. (c) Connections to Ground Rings. Where the grounding electrode conductor is connected to a ground ring as permitted in Section 250-50( d), that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than the conductor used for the ground ring. irC~t~iJ . . 250-68. Grounding Electrode Conductor Connection to Grounding Electrodes (a) Accessibility. The connection of a grounding electrode conductor to a grounding electrode shall be accessible. Exception: An encased or buried connection to a concrete-encased, driven, or buried grounding electrode shall not be required to be accessible. IIE~t~ii' (b) Effective Grounding Path. The connection of a grounding electrode conductor shall be made in a manner that will ensure a permanent and effective grounding path. Where necessary to ensure the grounding path for a metal piping system used as a grounding electrode, effective bonding shall be provided around insulated joints and sections and around any equipment that is likely to be disconnected for repairs or replacement. Bonding conductors shall be of sufficient length to permit removal of such equipment while retaining the integrity of the bond. !lE~~i~,~ . . 250-70. Methods of Grounding Conductor Connection to Electrodes The grounding conductor shall be connected to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means. Connections depending on solder shall not be used. Ground clamps shall be listed for the materials of the grounding electrode and the grounding electrode conductor and, where used on pipe, rod, or other buried electrodes, shall also be listed for direct soil burial. Not more than one conductor shall be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is listed for multiple conductors. One of the following methods shall be used: 1. 'A listed bolted clamp of cast bronze or brass, or plain or malleable iron 2. A pipe fitting, pipe plug, or other approved device screwed into a pipe or pipe fitting 3. For indoor telecommunications purposes only, a listed sheet metal strap-type ground clamp having a rigid metal base that seats on the electrode and having a strap of such material and dimensions that it is not likely to stretch during or after installation 4. An equally substantial approved meansc....:.;ta;~ E. Bonding . 250-90. General Bonding shall be provided where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed.