Separately derived system and electrode?

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dm9289

Industrial Maintenance Electrician
Location
Pennsylvania
Occupation
Industrial process repair/ maintenance Electrician
My situation has a 4000amp 480/277V system building main is switch gear.
Switch gear cabinet has large molded case breaker that feeds a fused disconnect.
Fuse disconnect has 4 wires 3 ungrounded conductors an a ground wire.
Fused disconnect goes in rigid conduit under cement for about 80 ft and emerges out of concrete to a wireway.
In wireway conductors are tapped to feed a transformer 480/240-120 single phase.
Two hots are tapped from 480 feed for xfrmr input and incoming ground wire from fused disconnect is ran to XO
240/120 output of transformer is connected with 2 hots and the neutral and ground to XO going to 120/240 panel neutral neutral bar ground to ground bar
Does this require a grounding electrode local to the transformer to attach to the XO such as building steel or rods.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
IMO, 250.121 Exception would allow the grounding conductor to serve as a GEC IF it is properly sized and properly installed (keep 250.64 in mind).
250.104(D) would stil require bonding in the area served by the SDS {See Info Note at 250.30(A)(4)}
 

dm9289

Industrial Maintenance Electrician
Location
Pennsylvania
Occupation
Industrial process repair/ maintenance Electrician
IMO, 250.121 Exception would allow the grounding conductor to serve as a GEC IF it is properly sized and properly installed (keep 250.64 in mind).
250.104(D) would stil require bonding in the area served by the SDS {See Info Note at 250.30(A)(4)}
Thanks for the input. I will read thru the references
 
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