Neutral conductor ....or No?

Z

zooby

Senior Member
Location
Indiana
Occupation
maint. electrician
Existing 13,200 -- 277/480 xfmr. Hits the (3) ATS's . All conduits leaving have BOY and N...and G.
New bldg being added. Contractor has pulled BOY and G to new ATS. Did the first contractor pull an unneeded conductor or is the current contractor wrong? Thanks for any help! Doug
 
zooby said:
Existing 13,200 -- 277/480 xfmr. Hits the (3) ATS's . All conduits leaving have BOY and N...and G.
New bldg being added. Contractor has pulled BOY and G to new ATS. Did the first contractor pull an unneeded conductor or is the current contractor wrong? Thanks for any help! Doug
Click to expand...
IMHO.... Current Contractor is wrong.
 
zooby said:
Oh --so each transformer is a service? or...maybe 250.24 (c) applies also? we do have selector switch in them for A-fed B-fed A/B and Loop-thru. That loop thru would be the "service disconnecting means"??
Click to expand...
No... Each Transformer is not a service. It can be a service if it's under the control of the PC. If its not, then its an SDS (Separately Derived System).
 
zooby said:
The 13,2 xfmr is part of our loop system [ 21 total ] and the main "switchgear" is of course where poco comes in. We own it all. that help?
Click to expand...
So these are transformer secondary conductors and a neutral is not required unless there are line to neutral loads fed from the ATS. Note that the grounding conductor between the transformer and the first OCPD is a supply side bonding jumper sized per Table 250.102(C)(1) and not an EGC sized by Table 250.122.
 
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