What is the distinction between 250.104 (A), Metal water piping, "General" & (B), "Other metal piping" ?
(A), (1) requires a Bonding conductor of a size based on Tbl 250.66. The Art permits one of the connection- points to be "the one or more Grounding Electrodes".I presume this would include the "Supplemental" Grounding Electrode which is permitted to be connected with a #6 copper conductor.
Another connection-point is the "Grounding Electrode Conductor where of sufficient size". The ambiguity to me is that the GEC is also a size based on Tbl 250.66. What arrangement would cause the GEC to be of "insufficient" size?
(B) "Other metal piping" permits a metal-pipe Bonding conductor of a size based on the rating of the C-B protecting the circuit that would energize the piping.
I percieve the Bonding conductor for metallic piping to have a basic purposes--- (1), to "set" the metallic surface at Ground potential, and (2), to conduct a fault-current directly back to the "source", the panel where the OCPD is located.
Permitting a connection to a Grounding Electrode appears to be an in-direct path for fault-current.
(A), (1) requires a Bonding conductor of a size based on Tbl 250.66. The Art permits one of the connection- points to be "the one or more Grounding Electrodes".I presume this would include the "Supplemental" Grounding Electrode which is permitted to be connected with a #6 copper conductor.
Another connection-point is the "Grounding Electrode Conductor where of sufficient size". The ambiguity to me is that the GEC is also a size based on Tbl 250.66. What arrangement would cause the GEC to be of "insufficient" size?
(B) "Other metal piping" permits a metal-pipe Bonding conductor of a size based on the rating of the C-B protecting the circuit that would energize the piping.
I percieve the Bonding conductor for metallic piping to have a basic purposes--- (1), to "set" the metallic surface at Ground potential, and (2), to conduct a fault-current directly back to the "source", the panel where the OCPD is located.
Permitting a connection to a Grounding Electrode appears to be an in-direct path for fault-current.
