(C) Continuous. Except as provided in 250.30(A)(5) and
(A)(6), 250.30(B)(1), and 250.68(C), grounding electrode
conductor(s) shall be installed in one continuous length
without a splice or joint. If necessary, splices or connections
shall be made as permitted in (1) through (4):
(1) Splicing of the wire-type grounding electrode conductor
shall be permitted only by irreversible compressiontype
connectors listed as grounding and bonding equipment
or by the exothermic welding process.
(2) Sections of busbars shall be permitted to be connected
together to form a grounding electrode conductor.
(3) Bolted, riveted, or welded connections of structural
metal frames of buildings or structures.
(4) Threaded, welded, brazed, soldered or bolted-flange
connections of metal water piping.