250.66

[spyderx92]

If you have 600 amp switchgear with two ground rods, can you run 6 awg from the panel to the two ground rods ? Or is that under size according to 250.66 table ? When do one use the tallest to size the the ground electrode conductor ?

Guy


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[infinity]

A GEC to a rod electrode is not required to be larger than #6.

Welcome to the forum.

250.66 Size of Alternating-Current Grounding Electrode
Conductor. The size of the grounding electrode conductor at
the service, at each building or structure where supplied by a
feeder(s) or branch circuit(s), or at a separately derived system
of a grounded or ungrounded ac system shall not be less than
given in Table 250.66, except as permitted in 250.66(A)
through (C).
(A) Connections to a Rod, Pipe, or Plate Electrode(s). If the
grounding electrode conductor or bonding jumper connected
to a single or multiple rod, pipe, or plate electrode(s), or any
combination thereof, as described in 250.52(A)(5) or (A)(7),
does not extend on to other types of electrodes that require a
larger size conductor, the grounding electrode conductor shall
not be required to be larger than 6 AWG copper wire or 4 AWG
aluminum wire.

 

[spyderx92]

so when do one use the table on the 250.66 to size their grounding conductor?

 

[infinity]

Are you asking about the (GEC) grounding electrode conductor?

 

[bwat]

For the other types of grounding electrodes as listed in Art 250. See specifically 250.52... ground ring.. water pipe.. etc.

There are others though, like Concrete Encased Electrode (Ufer), that is similar to ground rod in that it never needs to be larger than #4. (250.66(B))

 

[acin]

250 66 If it is not A B or C then go to the table